From: "Dewayne (n0ssy) & Linda (n0uqf) Hill" Subject: Easy Lehman adjustment Date: Fri, 02 Apr 1999 01:40:26 +0000 I have been running my Lehman for over two years and I guess you may be having the same problems I have. That being re-adjusting/re-leveling your Lehman. I have come up with a few things that may make this somewhat less of a hassle. Leveling base: I have a small bubble level super glued to the base running along the boom axis. This makes leveling the base easy. Leveling the Boom: I use a level that is designed to be suspended with a string. This type of level is used when you run a string between two points and you use the string as your guide. This level is duct taped to boom with the bubble up. Pick-up coil to magnet adjustment: I use double sided mounting tape to attach a 6 inch steel ruler to the lead mass (ruler sits horizontally and with the 6 inch mark inboard on the mass) and it extends 4 inches beyond the mass. I have made a pointer from thin aluminum that attaches to the base and extends up to and in front of the ruler. I bend the pointer where it points to the 1 inch mark on the ruler when the magnet/coil relationship is at it's magnum sensitivity. You may have noted that you get a larger trace at times as the boom naturally swings as your base tiles due to soil or temperature changes. When you are getting your largest traces (make sure an event is not causing this large trace HA HA) bend the pointer so that it is pointing to the 1 inch mark. You can then re-adjust back the 1 inch mark and be at the best setting for coil/magnet relationship. I hope these hints help you. Dewayne (n0ssy) & Linda (n0uqf) Hill Westminster, Colorado USA 39.83569n 105.0627w Elev. 5660ft. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: The Lahrs Subject: Re: Lehman electronics Date: Fri, 02 Apr 1999 06:42:09 -0700 Thanks, Dewayne & Linda, for your Lehman leveling suggestions. Has anyone posted a very readable and very simple circuit diagram for a Lehman amplifier/filter? I'll be getting a paper copy of the circuit that Sean-MT has posted, but am interested in others as well. I would like to come up with something that uses components that are very easy to obtain, such as from Radio Shack. Has anyone had problems with 60Hz noise? Does anyone use a differential input to reduce the 60Hz pickup? Does anyone use an instrumentation amp like an Analog Devices AD620? (I don't know what this is, but saw mention of it on another list.) How many stages of filtering (low pass poles) are required to get rid of the 60Hz noise? I want to find the least expensive way to power a Lehman amplifier. What source of power do you use? If it runs on 110V AC, does this add to the 60Hz noise? Thanks, John * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * AOL version of homepage: * * http://lahr.org/john-jan/homepage.html * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Feedback Loop Testing Date: Fri, 02 Apr 1999 08:42:02 -0800 Brett -- I looked at lpmeas.pdf this morning and this is great. It should be a great help to troubleshoot and fine tune seismometer and other feedback systems. In addition to injecting a voltage into the loop, one thing I might add (which you allude to), is to inject a current into a summing node of an inverting op-amp stage that is inside the feedback loop. Use a resistor in series with the function generator to establish the current, and adjust it by varying the output of the function generator and/or the value of the resistor. Sometimes, this can be easier than inserting a voltage. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: EVENT IN PROGRESS Date: Fri, 2 Apr 1999 20:00:52 +0200 Large event in progress. Vanuatu by Usgs. Org time : 17.23 utc I.E.S.N PSN Italy
Large event in = progress.
 
Vanuatu by Usgs.
 
Org time :  17.23 = utc
 
I.E.S.N  PSN=20 Italy
From: Brett Nordgren Subject: Re: Feedback Loop Testing Date: Fri, 02 Apr 1999 13:14:22 -0500 Karl, Thanks for the feedback. (no pun intended) Yes, indeed the current injection technique can be simpler in some cases. Think that will go into part 2. There's a little tradeoff since now your measurements have to be floating, (differential), and sometimes it's hard to get a big enough signal, measuring voltages across resistors. Wonder if anyone makes a low-frequency, very sensitive AC clip-on current probe? That would really be the tool for the job. BTW I noticed on Sean-Thomas' used equipment page a Tek 502 and a 502A scope. If they're still around and if anyone's close enough to afford the shipping (they're big & heavy) they are the ideal scope for making these measurements. If I remember the specs they're dual beam, DC-500 kHz, differential input, and sensitivity down to a few tens of microvolts. They have enough vacuum tubes to start a used parts business, but were very reliable. Highly recommended if they're still available. Final thought: You can also use a small transformer to inject an AC voltage. Something in the the Mouser TMxxx (200mW) line might work. The problem is that at 1Hz, you can only get a few MV out of them. A quick estimate of the max available output voltage is Sqrt(Rated power x Sec. Impedance) x Freq / Min. freq So at 1 Hz a transformer with 600 Ohm secondary, 200 mW power rating, with a 300 Hz minimum frequency spec. could (conservatively) deliver only Sqrt(0.2 x 600) x 1 / 300 = 36.5 mv RMS Have no idea whether it would put out anything at all like a sine wave but think it probably wouldn't be too terrible. With a decent scope that should be enough volts. Good luck with the measurements. Brett At 08:42 AM 4/2/99 -0800, you wrote: >Brett -- > >I looked at lpmeas.pdf this morning and this is great. It should be a >great help to troubleshoot and fine tune seismometer and other feedback >systems. > >In addition to injecting a voltage into the loop, one thing I might add >(which you allude to), is to inject a current into a summing node of an >inverting op-amp stage that is inside the feedback loop. Use a resistor in >series with the function generator to establish the current, and adjust it >by varying the output of the function generator and/or the value of the >resistor. Sometimes, this can be easier than inserting a voltage. > > > > >Karl Cunningham >La Mesa, CA. >PSN station #40 >karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: Lehman power supply Date: Fri, 2 Apr 1999 12:33:14 -0600 (CST) John, I have your SASE, and decided to take an hour or so and finish the new drawing of the amplifier so that it is more readable, but also so I can update it with new options and info, like parts availability from Radio Shack (a new RS store just showed up about a mile from my house here). THe amplifier reduces 60hz noise with two four-pole low pass filters with a corner at 20hz. By simply using 10 times the value of the four filter resistors, the corner can be reduced to 2hz, which is what we use for amplifying 15-second LP seismometers, providing a "Wood-Anderson" like response near 1 second. This is also a practical low-pass corner for a seismometer located in a residence; or like our SLM station which has been under the gym in the middle of the campus since 1923. I can also provide the transfer functions of the complete amplifier. One of the options I might pursue is drawing a parts layout for a perforated and solder-pad circuit board that RS carries. (If anyone has qualms about soldering, it is easy and worth learning to do.) Regarding the instrumentation amp and the differential input question: since the seismic amplifier is located at the seismometer, which is a relatively low impedance source, these are not needed, and only up the complication quotient. The input of the amplifier is "single ended", which means that one side is the circuit common. Regarding power for the amplifier: in a previous post I suggested using photo-lithium batteries if micro-power amps (LM4250, MC1776 etc) could be used to keep the current drain to less than 0.1 ma. An advantage of batteries is isolation from AC 60hz noise, and simplicity of installation, since only a high-level signal lead need to be run to the recorder or digitizer, with no ground loops. For use as an isolated amplifier, (installed in the borehole or near the seismometer or geophone), photo-lithium batteries can be used. A battery pack of 6 of the the AA size, configured for +,- 4.8 volts, will provide 100 microamps for 30 months or more. The AA size costs about $6 per pair. Larger lithiums will last for years, or the shelf life: 100 microamps is about the level of the internal leakage. If more common amplifiers are used, (I will see what RS has), power consumption may be tens of milliamps, so long term battery operation is not practical. But the amplifier needs a well-regulated bi-polar (+ and - voltages) supply. For the new STM-8 electronics, I have found a DC-DC converter from MOUSER that costs $19, and with an input of 9 to 18 volts (which could be a large 12-volt battery), it puts out +.- 15 volts at 100ma regulated to 1%. (Mouser #618-0BQ23WC1224; and as usual with Mouser, detailed specifications are minimal). But it does provide complete input-output isolation, so it is similar to a battery source. Physically, it is about two-thirds the size of a 9-volt battery. I power it from the AC line with a RS AC-DC power cube that puts out 12volts (actually closer to 14V) at 500 ma; RS cat. no. 273-1652D for $12. I cut the adapter plug off the power cube lead, but buying the mating socket for the plug may be more convenient. (If anyone wants to use this for a VBB system, I felt that further stability was required for operation of the displacement detector, so I regulate the +,- 15 volts to +,- 12 volts at 0.002% using an LM317M and a LM337M, with further noise suppression circuitry; I can provide the schematic, or will post it whenever I have time to spend updating the web site.) (By the way, I still have some SASEs from others that I haven't made the time to copy the requested material for ... yet). Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: Feedback Loop Testing Date: Fri, 02 Apr 1999 10:34:34 -0800 Brett -- There are commercially-made non-contact hall-effect devices for measuring current but I don't know how much noise they have. They are in the range of $17 ea and look like a small current transformer. Can't remember who makes them right now. There are a couple of somewhat more modern scope possibilities for low-level analog measurements: Tek 7A22 and 5A22 plug-ins go to ten microvolts per centimeter and have adjustable high-pass and low-pass filters and wide range offset controls. And they are solid-state. I picked up a 7A22 at a swap meet about 4 years ago for around $20. -- Karl At 01:14 PM 4/2/99 -0500, you wrote: >Wonder if >anyone makes a low-frequency, very sensitive AC clip-on current probe? >That would really be the tool for the job. > >BTW I noticed on Sean-Thomas' used equipment page a Tek 502 and a 502A >scope. If they're still around and if anyone's close enough to afford the >shipping (they're big & heavy) they are the ideal scope for making these >measurements. If I remember the specs they're dual beam, DC-500 kHz, >differential input, and sensitivity down to a few tens of microvolts. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: Lehman power supply Date: Fri, 2 Apr 1999 14:57:40 -0700 (MST) Hi Sean-Thomas, Thanks for the further information on the amplifier and power supply. You mentioned, "One of the options I might pursue is drawing a parts layout for a perforated and solder-pad circuit board that RS carries." How does this type of circuit board work? I'm familar with test boards where one just pushes the leads into the board, printed circuit boards with soldered connections, and wire-wrap boards with just a grid of holes. This must be something new. Cheers, JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: Re: Lehman power supply Date: Fri, 2 Apr 1999 19:30:40 -0600 (CST) John, THe perforated board I like to use for prototypes has a grid of holes on 0.1" centers. They have been around for about 20 years; there are various versions of how the printed foils are laid out, usually on one side of the board, called the "wiring" side. I usually use the Vector board #3677 because it has a printed/gold plated 22-pin edge connector on one side. (If I don't need the connector, I don't buy that version.) The boards have wide "busses" run around the edges and several times up the center that can be used for ground or common and power supplies. The rest of the area is filled with columns of plated foil three-hole pads. The 4.5" x 9" board has 6 columns of 72 pads each. The board can be cut to size with an office paper cutter. For my new power supplies for the VBB I cut it lengthwise, they cut off one connector terminal, so it would fit a standard 10-pin circuit card edge connector. The boards are not cheap; about $24 for this one. However, it can be cut up to make several circuits. The main advantage if it is the ability to mount all the components to standard dimensions and then to SOLDER all the connections; this makes a permanent circuit with much more reliability than push-in or even wire-wrap boards. For some applications requiring very low noise, a board with a continuous foil over all of one side as a ground plane can be used, but making sure that components don't short to the plane as their leads are pushed through to the "wiring" side is a problem (there is a tapered drill available to enlarge the clearances). I will try to get to Radio Shack and see what they have, and pass on the catalogue number. On the web site, there is a scan of the 4-amplifier seismic amplifier laid out on a 1.5" by 5" strip of this type of board. Unfortunately, it doesn't show the wiring side of the board. Next week I will scan both sides of the power supply board. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: Lehman power supply Date: Sat, 03 Apr 1999 13:27:46 -0800 John RS has solderless breadboards (push leads into)~$11. They also have a solder board with the same geometry as the solderless breadboard, so if you like your layout you can transfer the components directly.ICs run down the center. You don't need to wire wrap with this particular board(~2.5"x6"). They are around $3 also. Barry John Lahr wrote: > Hi Sean-Thomas, > > You mentioned, "One of the options I might pursue is drawing a > parts layout for a perforated and solder-pad circuit board that > RS carries." How does this type of circuit board work? I'm > familar with test boards where one just pushes the leads into > the board, printed circuit boards with soldered connections, > and wire-wrap boards with just a grid of holes. This must > be something new. > > Cheers, > JCLahr > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Quentin Wagenfield Subject: Torsion Seismographs Date: Sat, 03 Apr 1999 20:31:11 -0500 (EST) -- [ From: Quentin Wagenfield * EMC.Ver #2.3 ] -- Roger Baker and others interested in torsion seis might like to know that W.F. Spregnether Instrument Co. in St. Louis offered a torsion seis kit for amateur builders in the early 50s. A mirror on a vane attached to the filament reflected a light beam to a drum recorder using photo paper. The recorder was on a separate pier 32" away from the seis. The period was 1.5 seconds. An instruction book came with the kit,entitled "Instructions For Assembling and Installation of Spregnether Series AR Seismograph," that includes drawings and parts lists for the seis and the recorder. If the company is still around the book might be available. The address listed in the book was 4567 Swan Avenue, St. Louis, MO. Quentin Wagenfield 2815 Indian Hill Rd. SE Cedar Rapids, IA 52403 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: Re: Torsion Seismographs Date: Sat, 3 Apr 1999 20:51:24 -0600 (CST) The company is still around: www.sprengnether.com Naturally, their focus is now more on electronic sensors and recorders. Although the AR is history (the inevitable problem of high noise from too small a mass, and a horizontal sensor with all its tilt sensitivity, and photo-recording got costly). I do have a copy of the AR manual if someone is REALLY curious. It used trapped beads of oil surrounding the torsion wire to damp bowstring vibrations of the torsion wire. The better torsion sensors were made by another company, and we operated the last pair in the SLU network until about 15 years ago. We later replaced the photo-recording with a linear photo-detector that output a voltage proportional to the displacement of the light spot from the center of the diode array. This was intended to be a low-gain signal for a multi-channel digital system, where we planned to preserve the displacement magnification of 2600 that the original Richter magnitudes were based on. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Roger Baker Subject: Re: Torsion Seismographs Date: Sun, 04 Apr 1999 04:08:49 -0500 Friends, So far as I can tell, the natural advantage of a horizontal torsion seismometer is likely to be compact size, relatively little environmental sensitivity to temperature and magnetic fields, and good to excellent buildability by amateurs. As Benioff pointed out, they would seem to be appropriate for teleseismic events except the designers mistakenly thought that periods longer than six seconds were counterproductive. Back in those days, passive damping was the only option. As Sean Thomas points out, they are also sensitive tiltmeters, but I think no more so than a Lehman. The buildability comes from the fact that they are not much more than than a vertical wire stretched between two screws on a post with a weight attached off-center to the wire and leveling screws at the base of the post, surrounded by an enclosure to screen out air currents. A natural period of ten seconds or a little more is not hard to achieve, and this should be in the ballpark for teleseismics. In my opinion, optical detection is the way to go, what with cheap laser pointers, etc. Passive magnetic damping is easy to do with a copper vane and small magnet (dead hard drives costing a few dollars contain excellent flat rare earth magnets intended for head positioning). The most interesting application of a torsion instrument would be to use force feedback instead of passive damping, and for this purpose the little triangular head positioning coil from the hard drive could be mounted on the torsion beam just above the fixed hard drive magnet. The feedback electronics could be very low power and virtually identical to my Hi-Q vertical except that it would be a horizontal and easier to build, I believe. The forces involved are very small so a little op amp should be able to handle the feedback needed to restore the position of the beam, weighing on the order of one ounce (one 324 op amp works for my vertical so a torsion instrument where the force is nearly balanced in the horizontal plane should require even less). I had fun building a rough prototype without damping, using a mirror on the torsion beam and a laser pointer to see how long I could adjust the natural period. I got it up as long as 30 seconds, but this won't hold for very long. I found that I could detect my own weight flexing the concrete slab of my foundation when I stepped to one side of the instrument, which is about six inches square and 18 inches tall with a tall glass enclosure. I think a Lehman would be expected to give somewhat similar results in terms of natural period and tilt sensitivity. --Yours, Roger Baker _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brian Chesire Subject: Re: Torsion Seismographs Date: Sun, 04 Apr 1999 07:44:50 -0700 For Anyone interested; the original construction article on the torsion seismometer was published in Scientific American's Amateur Scientist column. It was reprinted in a collection of these columns, "The Scientific American Book of Projects for the Amateur Scientist", edited by C.L. Stong. Should still be available thru your local library. The oil drops were used to damp the torsion fiber and the vane was megnetically damped. Brian Tucson, AZ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: The Lahrs Subject: Breadboards Date: Sun, 04 Apr 1999 09:01:11 -0600 Barry, Thanks for the tip on Radio Shack breadboards. I'm using the push-in style now for the prototype, so it would be easiest to switch to the same hole configuration when I'm ready to commit to solder. I've actually got a system running now that is sensitive enough that I get a big deflection when I stand next to the instrument. It's located on the brick fireplace hearth in the basement. The basement floor is a concrete slab. There are still lots of warts. I'm using two 9V alkaline batteries for power, as I haven't built a +- 15 V supply yet. The 60 Hz problem went away when I took Sean-T's advice and moved my low-pass filter corner to 2 Hz and reduced my sample rate to 5 Hz. The system is under damped, as I'm still using the original 4 ohm speaker coil with a 3 ohm damping resistor. I'm afraid if I get the damping resistor down to zero the system will still be under damped. Sean-T warned about this, but I couldn't resist using the original speaker coil because I was anxious to get it running. I suppose I could use eddy current or oil damping... I don't have a zero adjust for the amplifier yet, to there is a permanent DC offset of 1 Volt! Oh well, it's a start. ***** Quentin, Good to hear from Cedar Rapids. My mother is from Cedar Rapids and I still have an Uncle and Cousin on my father's side living there. So if you run into any Lahrs, say hello for me. John * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * AOL version of homepage: * * http://lahr.org/john-jan/homepage.html * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: SW6079@....... Subject: Re: Breadboards Date: Sun, 4 Apr 1999 11:43:54 EDT I have had my Lehman up for about a year. I tried electronic dampening after trying eddy-current (extremely touchy) I use two plates attached to the boom that are partially immersed in synthetic automotive oil of the lowest viscosity I could find. (Mobile one 5W) My wife hasn't missed the Tupperware yet, fortunately. Good Luck to you, Mike, N7ORL, sw6079@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Phil Schmidt Subject: Electromagnetic damper Date: Mon, 05 Apr 1999 00:57:59 +0900 G'day all I was wondering if anybody has tried using a partly energised (if that is how you spell it) solenoid as a damper. If not please could you point out to me the bad points involved with it. I was planning to use this for my instrument when I finally get around to building it. Cheers Philip Schmidt (australia) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: Electromagnetic damper Date: Sun, 04 Apr 1999 10:33:04 -0700 Philip -- I think that would work if you use a non-magnetic (but conductive) slug instead of the regular armature for the solenoid. Copper would work best because of its high conductivity. Using the solenoid sounds like a good plan because you could adjust the damping by changing the current through the coil, but the heat generated by the coil could cause undesirable convection currents. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... At 12:57 AM 4/5/99 +0900, you wrote: >I was wondering if anybody has tried using a partly energised (if that is >how you spell it) solenoid as a damper. If not please could you point out >to me the bad points involved with it. I was planning to use this for my >instrument when I finally get around to building it. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: damping 4 ohm coil Date: Sun, 4 Apr 1999 13:22:00 -0500 (CDT) John, I just had an idea that relates to the problem of electromagnetic damping of a seis with an unusual coil. We encountered this with the HGLP (high-gain long period) project of trying to separate mantle Raleigh waves from Love waves with the HGLPs and 30-meter long quartz strainmeters. The LP seismometers had 100,000 ohm signal coils, which would not pass enough "back EMF" current for damping. So we had secondary damping coils of the standard 500 ohms that did the damping properly. For the 4 ohm speaker coil, I have found that I can easily wind secondary coils for calibration just above the coil toward the remnant of the speaker cone. These do not fit into the magnet gap, but are just above it, where the magnetic field is perhaps 10 to 20% of the field in the gap. For my calibration coils, 5 turns is enough to drive the coils to the stops with 10 to 20 microamps. In the photos of the STM seis, they are clearly visible as the green coils above the magnet. For an auxillary damping winding, you would probably need at least several times the number of turns of the 4 ohm coil, wound with somewhat fine wire, like #36. I don't know how practical this might be. I made a temporary arbor and shaft arrangement to hold the coil with a pill bottle fitted inside of it so every turn could be placed properly. Another thought is that 3 ohms SHOULD properly damp a 4 ohm coil. (I can repeat the damping calculations note if anyone wants it.) But if the 3 ohms is outside of the seismometer, the resistance of the leads might be several ohms, resulting in under-damping. (this problem is addressed in stereo systems by using "mega" wire to the amplifier, which is what actually damps the speaker). Since running large wires off the seismometer boom and across the hinge will not work, I would suggest installing the 3 ohms directly across the 4 ohm coil on the boom, if you haven't done so already. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: RLLaney@....... Subject: Winquake--printing location map Date: Sun, 4 Apr 1999 19:21:03 EDT Question for Winquake users: I use Windows 95. When I try to print the location map for an event, I get an error message that says "This program has performed an illegal operation and will be shut down." If I close or exit it kicks out of Winquake. I can save the file and make a print with a viewer program, but it would be more convenient to print directly from Winquake. Has anyone else had this problem? Thanks. Bob Laney Herndon, VA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ted Blank Subject: Re: Lehman power supply Date: Sun, 4 Apr 1999 18:58:47 -0700 (PDT) Thank you S-T for offering the option of the "power cube" to power the amp. (By power cube I hope and assume that you mean one of the ubiquitous plug-in-the-wall xformers that put out 12 or 15V AC. The important thing is that this cube must be UL approved for any kind of use with schools. I would not let my kids use an amp which brought 115VAC into any kind of home-made case no matter how good I was at circuit design. LAast week we had a fire inspection at our schools and the little amplifier was approved because the xformer was standardd UL-approved. The only problem was that I used an extension cord between the cube and the wall. That was a no-no for the fire chief, so I had to move the amp closer tothe power outlet. Ted Blank San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: Breadboards Date: Sun, 04 Apr 1999 20:39:33 -0700 John Larry has a great circuit diagram for his amp board, which includes a zero adjust a 4 or 6 pole low pass. Not to push RS but they also have a small publication on power supply construction. I've used eddy current in the past and it works well. As STM mentioned before, the amount of damping is harder to adjust with this. I used a pair of opposing magnets(surplus harddrive magnets I think) with a vane of aluminum between. I found by varing the surface area of the vane between the magnets I could vary the damping. The vane moves parallel to it's plane. The nice thing about eddy current is it's not as temperature sensitive as oil viscosity. Barry The Lahrs wrote: > Barry, > > Thanks for the tip on Radio Shack breadboards. I'm using the push-in > style now for the prototype, so it would be easiest to switch to the > same hole configuration when I'm ready to commit to solder. > > I've actually got a system running now that is sensitive enough that > I get a big deflection when I stand next to the instrument. It's located > on the brick fireplace hearth in the basement. The basement floor is a > concrete slab. > > There are still lots of warts. I'm using two 9V alkaline batteries for > power, as I haven't built a +- 15 V supply yet. The 60 Hz problem went > away when I took Sean-T's advice and moved my low-pass filter corner to > 2 Hz and reduced my sample rate to 5 Hz. The system is under damped, as I'm > still using the original 4 ohm speaker coil with a 3 ohm damping resistor. > I'm afraid if I get the damping resistor down to zero the system will > still be under damped. Sean-T warned about this, but I couldn't resist > using the original speaker coil because I was anxious to get it running. > I suppose I could use eddy current or oil damping... I don't have a > zero adjust for the amplifier yet, to there is a permanent DC offset of > 1 Volt! Oh well, it's a start. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: The Lahrs Subject: At Last! Date: Sun, 04 Apr 1999 22:21:41 -0600 At last the beta version of the Ambrisco-Lahr seismograph station is running! Thanks for everyone's help. I still plan on making a lot of changes, but it feels good to have recorded an earthquake. http://lahr.org/john-jan/psn/psn.html Here's the screen dump: http://lahr.org/john-jan/psn/psn.html John * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * AOL version of homepage: * * http://lahr.org/john-jan/homepage.html * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: At Last! Date: Sun, 04 Apr 1999 23:08:24 -0600 John- What a Wiggle! A small step for the PSN, A BIG step for the USGS!! Congratulations! You are a credit to your Federal Agency! -Edward The Lahrs wrote: > At last the beta version of the Ambrisco-Lahr seismograph station is running! > Thanks for everyone's help. I still plan on making a lot of changes, but > it feels good to have recorded an earthquake. > > http://lahr.org/john-jan/psn/psn.html > > Here's the screen dump: > http://lahr.org/john-jan/psn/psn.html > > John > > * John C. and Jan H. Lahr * > * JohnJan@........ * > * 1925 Foothills Road * > * Golden, Colorado 80401-1718 * > * (303) 215-9913 * > * http://lahr.org/john-jan * > * AOL version of homepage: * > * http://lahr.org/john-jan/homepage.html * > * http://giseis.alaska.edu/lahr * > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: DC power cubes Date: Mon, 5 Apr 1999 00:35:16 -0500 (CDT) Ted, John, and co. Ted brought out one of my main concerns about powering the amplifier, specifically that the power supply must be UL approved if it is to be used in any public place like a school. The RS 12 volt, 500ma is UL listed, although this is not mentioned on the box, but on the label on the transformer. The adapters listed in NEWARK are all approved. Just to clarify a point, the ones I use put put a nominal 12 volts DC, not AC, which simplifies their use. In fact, if only OP amps are used, and nothing in the circuit is specifically dependent on the supply voltage value (like a DC offset adjustment), a PAIR of AC-DC power cubes is all that is needed: one for the positive supply, the other for the negative; one side of each output lead is common. So a complete supply can be bought for around $20 when the adpters are on sale. Each could be regulated to 1% with a LM7808/LM7908 3-terminal regulator. It is important to protect the AC-DC supply from overload. Some larger units have a mini circuit breaker; others are specifically listed as impedance protected, but cost much more. I use 10 ohm, 1/2 watt resistors as the fuses at the DC input terminals to protect the power cube from a shorted output. The little resistors do nothing at less than a 200ma load (0.4 watt), but at the 500 ma maximum (2.5 watts), they go up in smoke and let one know of a short. Of course, regular pigtail fuses can also be used. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "David A. Nelson" Subject: large STH Pacific quake NOW!!!!! Date: Mon, 5 Apr 1999 23:36:24 +1200 P arrival ~11:15 UTC very large S wave still coming in NOW 11:36 UTC Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://www.seismicnet.com/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Giovanni Rotta" Subject: STH PACIFIC EVENT Date: Mon, 5 Apr 1999 13:49:57 +0200 Italian stations reports a large quake in progresso now (Sth Pacific) Giovanni Rotta Via F. Pizzigoni, 10 33010 Resia (Udine) I Lat. 46.373 N Long. 13.305 E rottag@.......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Francesco Subject: PACIFIC EQ IN PROGRESS Date: Mon, 05 Apr 1999 14:23:27 +0200 STILL IN PROGRESS. VERY LARGE L, R FIJI ISLANDS? I.E.S.N. PSN ITALY Station: Osimo, I. 43.290N 13.294E _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Francesco Subject: EQ PR LOCATION Date: Mon, 05 Apr 1999 14:43:55 +0200 Preliminary location & M 10.200 km from Osimo, Italy. Philippine Sea ~ Ms ~ 7 I.E.S.N. PSN ITALY _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: At Last! Date: Mon, 05 Apr 1999 06:28:24 -0700 John Congratulations! BTW when it rains it pours. Did you record the New Britain Region event this am? Barry The Lahrs wrote: > At last the beta version of the Ambrisco-Lahr seismograph station is running! > Thanks for everyone's help. I still plan on making a lot of changes, but > it feels good to have recorded an earthquake. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: Torsion Seismographs Date: Mon, 05 Apr 1999 10:50:59 -0700 (MST) On Sun, 4 Apr 1999, Roger Baker wrote: > currents. A natural period of ten seconds or a little more is not hard to > achieve, and this should be in the ballpark for teleseismics. One could easily increase the moment of inertia of such a device by adding "arms" which could greatly increase the period. I am also thinking that if these arms had large rigid fins to INCREASE air resistance (this sounds weird at first, I know) like paddles you could come close to approximating the actual rotation of the ground because the frame will move with respect to the ground, but the rotating assembly will be "stuck" to the air. This does increase the possibility of thermal and other air noise from overwhelming the recording, but I think if it were placed in a large temperature controlled and dessicated barrel or something like that it might alleviate that problem. Oh, also a quick word on reducing thermal gradients. If you use two layers of insulation sandwiched around a good thermal conducting layer you will be able to spread the heat out enough and reduce the bad effects of having different portions of the air around your seismometer at different temperatures... This works by allowing low heat flux into the first layer, which conducts heat much slower than the fast conducting layer, and so the heat flux spreads around the conducting layer and then moves slowly again through the inner insulation. John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: meredith lamb Subject: Re: At Last! Date: Mon, 05 Apr 1999 14:22:12 -0600 Congratulations on the new up and improving seismograph station. I note the new program for use with the card you are using....it should be of alot of interest to many people. Amazing how you come out with so many computer programs....thanks and congratulations again! Meredith Lamb The Lahrs wrote: > At last the beta version of the Ambrisco-Lahr seismograph station is running! > Thanks for everyone's help. I still plan on making a lot of changes, but > it feels good to have recorded an earthquake. > > http://lahr.org/john-jan/psn/psn.html > > Here's the screen dump: > http://lahr.org/john-jan/psn/psn.html > > John > > * John C. and Jan H. Lahr * > * JohnJan@........ * > * 1925 Foothills Road * > * Golden, Colorado 80401-1718 * > * (303) 215-9913 * > * http://lahr.org/john-jan * > * AOL version of homepage: * > * http://lahr.org/john-jan/homepage.html * > * http://giseis.alaska.edu/lahr * > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: Feedback Loop Testing Date: Mon, 05 Apr 1999 19:37:11 -0700 Brett I agree w/ Karl, nice work! BTW Harris/Intersil make a precision waveform generator which outputs sine/square/triangle wave forms(ICL8038). Output is ~0.2 V supply @ 0.001hz to 300khz! With a output buffer and going thru the transformer primary would this provide the needed source at the secondary? Barry Brett Nordgren wrote: > Karl, > > Thanks for the feedback. (no pun intended) > > Yes, indeed the current injection technique can be simpler in some cases. > Think that will go into part 2. There's a little tradeoff since now your > measurements have to be floating, (differential), and sometimes it's hard > to get a big enough signal, measuring voltages across resistors. Wonder if > anyone makes a low-frequency, very sensitive AC clip-on current probe? > That would really be the tool for the job. > > BTW I noticed on Sean-Thomas' used equipment page a Tek 502 and a 502A > scope. If they're still around and if anyone's close enough to afford the > shipping (they're big & heavy) they are the ideal scope for making these > measurements. If I remember the specs they're dual beam, DC-500 kHz, > differential input, and sensitivity down to a few tens of microvolts. They > have enough vacuum tubes to start a used parts business, but were very > reliable. Highly recommended if they're still available. > > Final thought: You can also use a small transformer to inject an AC > voltage. Something in the the Mouser TMxxx (200mW) line might work. The > problem is that at 1Hz, you can only get a few MV out of them. > > A quick estimate of the max available output voltage is Sqrt(Rated power x > Sec. Impedance) x Freq / Min. freq > > So at 1 Hz a transformer with 600 Ohm secondary, 200 mW power rating, with > a 300 Hz minimum frequency spec. could (conservatively) deliver only > Sqrt(0.2 x 600) x 1 / 300 = 36.5 mv RMS Have no idea whether it would > put out anything at all like a sine wave but think it probably wouldn't be > too terrible. With a decent scope that should be enough volts. > > Good luck with the measurements. > > Brett > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Re: Feedback Loop Testing Date: Tue, 06 Apr 1999 08:56:25 -0400 Barry, Glad you could use the info; thanks for the comments. I've been occasionally checking the surplus market for a generator along those lines, myself. Yes, your approach should work fine. Wasn't sure if you were suggesting trying to measure below 1 Hz. Getting much below 1 Hz using a transformer would be problematical; the max Vout gets awfully small. You really don't need to, as the low frequency loop gain is easily calculated. It's only at the higher frequencies, where all the problems happen that you'll likely need to be measuring. If you really do want to get down low (and can measure the milli-Hz) the instrumentation amp approach would probably work out best. I don't have the STM-8 circuit handy, but as I recall I hadn't spotted a really ideal place for voltage injection. Believe I was thinking you could temporarily stick in a X1 buffer amp to manufacture a good break point. Hmmm, if you did that, there might be some way to use it also to inject the voltage. I wonder.... It looks as if you'll need a few (1 to 6) volts to drive a transformer to its max voltage capability at 1Hz. At that frequency, the load impedance on your buffer will be mainly the primary winding resistance of the transformer, and the source impedance to the seismo circuit will be its secondary winding resistance. Mouser is very good about listing the parameters for all their audio transformers. Regards, Brett At 07:37 PM 4/5/99 -0700, you wrote: >Brett > I agree w/ Karl, nice work! BTW Harris/Intersil make a precision waveform >generator which outputs sine/square/triangle wave forms(ICL8038). Output is >~0.2 >V supply @ 0.001hz to 300khz! With a output buffer and going thru the >transformer primary would this provide the needed source at the secondary? > Barry > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Re: Feedback Loop Testing Date: Tue, 06 Apr 1999 06:36:28 -0700 I have noticed that the online auction site ebay.com appears to be a good place to buy test equipment--oscilloscopes, meters, power supplies, function generators. Of course, real PSN folks would build their own, but you could always buy a broken one and fix it. -- Doug Crice web site http://www.georadar.com GeoRadar Inc. e-mail dcrice@............ 19623 Via Escuela Drive phone 408-867-3792 Saratoga, CA 95070 USA fax 408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Re: Feedback Loop Testing Date: Tue, 06 Apr 1999 10:18:26 -0400 Doug, Good idea. I haven't tried ebay yet. Another interesting looking place for all kinds of scientific equipment is at: http://www.labx.com/ They sell surplus items direct as well as a having an ongoing auction. Have a lot of >$5k big instruments like gas chromatographs, etc., but also much interesting small stuff. Yesterday I bid on and got a spring tester that looks as if it could be adapted to measure "our" kind of springs. Should be interesting. Anyone else know of good online sources for useful (cheap) items? Regards, Brett At 06:36 AM 4/6/99 -0700, you wrote: >I have noticed that the online auction site ebay.com appears to be a >good place to buy test equipment--oscilloscopes, meters, power supplies, >function generators. Of course, real PSN folks would build their own, >but you could always buy a broken one and fix it. >-- >Doug Crice web site http://www.georadar.com >GeoRadar Inc. e-mail dcrice@............ >19623 Via Escuela Drive phone 408-867-3792 >Saratoga, CA 95070 USA fax 408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: At Last! Date: Tue, 6 Apr 1999 12:42:28 -0600 (MDT) Yes, I sure did! It was on the boundary of two hour-long files, so I have to figure out a way to combine the files. JCLahr > > John > Congratulations! > BTW when it rains it pours. Did you record the New Britain Region event this > am? > Barry > .. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ted Blank Subject: Re: Power cubes Date: Wed, 7 Apr 1999 02:17:35 -0700 (PDT) Larry has found a source for UL-approved power cubes which provide +/- 15VAC from a single cube. I guess he rectifies it on the board. This is the power supply he ships with his amplifier card. Ted Blank San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "jim E O'Donnell" Subject: Re: Info on your kc1 Date: Wed, 7 Apr 1999 11:58:07 -0700 Hi Karl, By way of introduction I am a retired geophysicist living near Las Vegas and am interested in your kc1 sensor. Your 990407a.kc1record is very nice! ML=4.1 @ 78 km's........... What type of FB did you build? Also your site seems very quiet... What is the smallest local Eq., Mag., (say from 10 to 100 km's away) can you record? Best guess answer... I am in the process of converting UNLV's, E-W, 20 year old analog Lehman to a digital with Larry's boards which are on order, but I want to record local Eq's and feel a FB is the way to go and will eventually need a vertical to see Rayleigh waves. Appreciate any info you or others can give me, the STM-8 may be the way to go but looks tough to build. I have a standing offer to the engineering students at UNLV that I will supply all the pieces and Sean's schematic, if they want to get some research units and have some fun. No takers yet! Has any one built a STM-8 yet, besides Sean? I have two colleagues, both academic types, Tom McEvily, UCB,and Fred Followill, LLNL, who profess to and marvel at Sean's knowledge and ability in seismometry. Best Regards, Jim O'Donnell 661 Del Prado Dr. Boulder City, NV 89005 702 293-5664 jimo17@........ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: More feedback testing Date: Wed, 07 Apr 1999 18:07:39 -0400 To all, The feedback testing file has been expanded to 47k. Lots more words, a little more content. new file name is lpmeas2.pdf - 47k at: http://members.home.net/nordgren/public/ Good luck with the measuring. Brett Nordgren _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: Info on your kc1 Date: Wed, 07 Apr 1999 18:32:13 -0700 Hi Jim I have built two SMT-8 style units using STM's design with some modifications. The larger, of similar size to Sean's works well. I think it has performed better than my Lehman for events further than 150-200km. It has been in operation for a several months. I have also been experimenting with a smaller (12" boom) for a while. I was thinking of using a smaller unit in the field. I have recently also set up a 12" long horizontal with the "triple feedback" but have not had satisfactory performance as yet. I would be glad any construction experiences. Sean would be the better choice, since he understands the design more completely. I have been having some periodic problems but I think they are related to my site location(on a detached garage slab) . Regards Barry jim E O'Donnell wrote: > Hi Karl, > ---snip---- > Appreciate any info you or others can give me, the STM-8 may be the way > to go but looks tough to build. I have a standing offer to the > engineering students at UNLV that I will supply all the pieces and Sean's > schematic, if they want to get some research units and have some fun. No > takers yet! Has any one built a STM-8 yet, besides Sean? I have two > colleagues, both academic types, Tom McEvily, UCB,and Fred Followill, > LLNL, who profess to and marvel at Sean's knowledge and ability in > seismometry. > > Best Regards, > > Jim O'Donnell > 661 Del Prado Dr. > Boulder City, NV 89005 > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Steve Hammond Subject: Re: At Last! Date: Thu, 08 Apr 1999 05:49:56 -0700 Hi John, looks like you are swinging... I like the upper wire idea. keep us posted. Regards, Steve Hammond The Lahrs wrote: > > At last the beta version of the Ambrisco-Lahr seismograph station is running! _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: Info on your kc1 Date: Thu, 08 Apr 1999 00:07:57 -0700 Hi Jim -- Thanks for your comments about the 990407a.kc1 record. This was a close/strong event -- way above the noise level so it looks pretty clean. I have some details of the FB construction at http://www.jps.net/karlc/ . I keep the gain of each channel as low as I can and still resolve events that are just above the noise. That's so I can capture "the big one" onscale. The largest continuous noise source is the 6-second background which seems to correlate with Pacific storms. Recently, it's been pretty high. My site is semi-rural and other than noise generated by our family around the house, there is the occasional truck that goes by but that's about it. As far as recording small events, on quiet background days I often see M1.2's at 100km on the acceleration output, which favors local events because of its sensitivity to higher frequencies. The smallest event I've seen at this distance is M1.0. During Winter, the background noise is rarely low enough to see these events. As far as what to build, these days I'd opt for a VBB instrument like Sean-Thomas' STM-8. For one thing, it's a vertical. Also, it looks a lot easier than what I built and probably works better too. My instrument produces an acceleration output which has to be electronically integrated to velocity (because that's what everyone likes to see for event records), but the VBB produces a velocity output directly. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... At 11:58 AM 4/7/99 -0700, you wrote: > By way of introduction I am a retired geophysicist living near Las Vegas >and am interested in your kc1 sensor. >Your 990407a.kc1record is very nice! ML=4.1 @ 78 km's........... >What type of FB did you build? >Also your site seems very quiet... >What is the smallest local Eq., Mag., (say from 10 to 100 km's away) can >you record? Best guess answer... > >I am in the process of converting UNLV's, E-W, 20 year old analog Lehman >to a digital with Larry's boards which are on order, but I want to record >local Eq's and feel a FB is the way to go and will eventually need a >vertical to see Rayleigh waves. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: BIG QUAKE Date: Thu, 8 Apr 1999 17:36:56 +0200 FROM ALL ITALIAN STATIONS P and S WAVE IN SATURATION 120' OF REC PRELIMINARY LOCATION: SEA OF JAPAN MS 7.5
FROM ALL ITALIAN = STATIONS
 
P and S WAVE IN = SATURATION
 
120' OF REC
 
PRELIMINARY = LOCATION:    =20 SEA OF JAPAN       MS =20 7.5
From: "Francesco" Subject: R: BIG QUAKE Date: Thu, 8 Apr 1999 17:47:42 +0200 USGS BULLETIN 99/04/08 13:10:34 43.60N 130.53E 559.5 7.2Mw A E. RUSSIA-N.E. CHINA = BDR REG I.E.S.N. PSN ITALY
USGS BULLETIN

99/04/08 =20 13:10:34  43.60N 130.53E 559.5 7.2Mw A  E. RUSSIA-N.E. CHINA = BDR=20 REG
 
I.E.S.N.   PSN=20 ITALY
From: robert barns <75612.2635@..............> Subject: Re: Feedback Loop Testing Date: Thu, 8 Apr 1999 13:48:00 -0400 Doug, Brett pointed out to me another on-line auction which has electronics a= nd lab equipment, it is www.labx.com The few items I looked at seemed to have low prices. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: VBB and local quakes Date: Thu, 8 Apr 1999 22:38:30 -0500 (CDT) Jim, Regarding recording smaller local quakes: A truly VBB seismometer will have a flat velocity response over a very wide range of frequencies, so it will record local and near- regional quakes just as well as teleseisms. THis, along with the very high dynamic range (the ratio of the self noise to the maximum signal) is why VBB sensors are so attractive, since one of them can replace several of the classic narrow band seismometers. Of course, the quality of the instrument site becomes most important in assessing the threshold of sensitivity to small earthquakes. The main two limitations are the level and tolerance of local noise that we call "cultural", like trucks, trains, farming, people. Like any unusual but continuous noise that quits for lunch is suspect, like a bulldozer in a new subdivision somewhere nearby. THe usual solution to cultural noise is low-pass filtering. Since I am so close to a street here, I have considerable filtering at about 4 hz to reduce the noise. But I still successfully record small New Madrid quakes on my monitor record; The report figures show a Mb 3.8 at a distance of 350 km. I suppose I should try to scan some local events for the web figures, but I'm not sure that the resolution would be adequate. The other limit to the frequency response of a VBB system is the sample rate you want to deal with. FOr teleseisms, 1 sample/second is usually adequate, although most broadband stations use 20sps for the main VBB data stream. Now that umpti-gigabyte drives are available, several days of such data can be stored for many channels at 24-bit resolution. A sample rate of 20sps will resolve 10 hz (the "Nyquist" frequency). But most local quakes have energies upwards of 25 to 50 hz, so sample rates of 50 to 100 hz are needed. These files can fill up a disk quickly unless the data is saved by some event detection method. On the other hand, the IRIS stations save 40sps data continuously as part of the non-proliferation treaty data set. But since a VBB sensor is flat to velocity from, for example, 120 seconds to 50 hz, a single sensor can be the input for several different sample rates. The IRIS stations, with STS-1s, sample each sensor at 4 different rates (20, 1, 0.1, 0.01 sps). An appropriate low-pass filter is needed for each rate to prevent aliasing. Unfortunately, I am not aware of any "affordable" digtizer that allows multiple sample rates. One last note; if your students ever get serious about building the STM-8 vertical, be sure to send me an address label and 6 33-cent stamps (I have plenty of envelopes) for a copy of the report and, most importantly, a package of the very latest versions of the drawings and schematics. I just got caught up on a backlog of SASE requests by including a set of this latest info. Naturally, within minutes of depositing them at the postoffice, I found a number of errors and typos. I do the mechanical drawings with a cad program, so they are accurate enough to be scaled up to real size with a copier, then used as actual patterns for the various pieces. The major shortcoming of the drawings is that I have not done an overhead view of the seismometer, but the web photos seem to be able to provide enough info to fill out what is not in a drawing. As I have mentioned before, I am working on getting a commercial source for the electronics. Nothing is certain yet. I am also making some progress on a pressure containment for the vertical sensor. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: Your Message Sent on Thu, 8 Apr 1999 18:31:56 -0500 Date: Fri, 9 Apr 1999 08:21:06 -0600 (MDT) Albert, Are you familiar with the Public Seismic Network group? This is an informal, international group of people interested in seismology, and much of the discussion is on building seismograph equipment. However, questions of seismogram interpretation are also discussed. Check out this web site for more information: http://psn.quake.net/ JCLahr > From: "Albert Hrubetz" > To: "<\"John C Lahr, Lakewood, CO \"" > Date: Thu, 8 Apr 1999 18:31:56 -0500 > MIME-Version: 1.0 > X-Priority: 3 > X-MSMail-Priority: Normal > X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3110.3 > > John: > > Thank you for considering an explanation on the web site for the various seismic ray paths. I have Bolt's EARTHQUAKES, Macelwane's WHEN THE EARTH QUAKES and Macelwane's THEORETICAL SEISMOLOGY, none of which carry the nomenclature of the referenced Earth Model. Analysis of ray paths is quite fascinating, and today's China/E. Russia quake, for example, looks like a ray-path bonanza! I wish I could understand many of the later events. > Thanks again and regards, > > Albert Hrubetz _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: From Edward out in the field... Date: Sat, 10 Apr 1999 00:30:59 -0700 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% published thursday, april 8, 1999, in the san jose mercury news residents can help usgs scientists by allowing seismometers in yards this weekly feature looks at area issues and people in a question-and-answer format. By glennda chui mercury news staff writer today through sunday, government scientists will be knocking on doors of homes in the northeastern santa clara valley, asking if they can install seismometers in back yards for a study that could better define how the ground shakes in an earthquake. We talked about the project with four researchers from the u.s.geological survey: david carver and arthur frankel from the denver office as well as allen lindh and jon fletcher, who work out of menlo park. Why this part of the valley? It lies directly over a hidden geological formation, known as the evergreen basin, that could intensify and focus the energy of an earthquake. Although the basin is six to nine miles long, three to five miles wide and more than two miles deep, you can't see it because it filled up with sediment over the past 65 million years. A similar basin, known as the cupertino, lies under the west side of the valley. Why are these basins important? These formations can trap and bend earthquake waves, prolonging shaking and directing seismic energy into specific areas. They were a factor in the damage from the 1994 northridge earthquake and the 1995 quake in kobe, japan. Preliminary studies show they could also play a part here. What did those studies show? Last summer, lindh and his colleagues installed 40 seismometers in the backyards of volunteers throughout the valley. So far, frankel said, the results indicate that in some earthquakes, parts of the evergreen basin shook somewhat harder than comparable sites outside the basin. The increase took place in seismic waves that are just the right size to affect buildings of roughly two to 10 stories. The scientists haven't seen any increase in shaking in cupertino, but they have not finished their analysis. Is that something we should worry about? ``I don't think so,'' frankel said. "The types of seismic waves most likely to be amplified by a basin are the long, slow rollers that are damaging to tall buildings, bridges and other large structures, but not to houses more commonly found in this area. So it would be premature to say this was a particularly dangerous area for single-family homes, frankel said. ``All this stuff is at a very early stage and we don't have a lot of data so far.'' how is the new study different? This time researchers want to put their instruments much closer together and concentrate them in the area where the basin is deepest. They installed the first seven seismometers in february, in a line roughly parallel to berryessa road from highway 101 to the hills. They have 33 more to go, laid out in a grid of triangles so the instruments are exactly one kilometer (0.6214 miles) apart. ``I need these instruments to be where we've got the dots'' on the map, carver said. ``I'm having to knock on peoples' doors to get that precise spot. That's the tough part of this project. People are naturally wary of people knocking on their door and asking for something. I have to get beyond that.'' if he can't hit a dot dead-on, he'll try for a location less than the length of a football field away. What's involved in hosting one of these seismometers? Almost nothing. ``It does require power, so they have to keep it plugged in,'' carver said. The seismograph uses about as much electricity as a night light. If there's a power outage, it can run on batteries for up to two days, and then reboot itself when the electricity comes back on. Researchers come out to maintain the machine every few months and will also stop by to retrieve data if there's a large quake. They can remove a seismograph or fix problems that come up within a couple of days. ``Please try to keep the kids off the thing,'' carver said. ``But they can't damage it unless they make a concerted effort.'' what do the scientists hope to find out? ``Once we have a model of the basin that we can do our computer simulations in, hopefully we'll learn how to make an accurate model so we can predict these kinds of ground motions in other places too,'' frankel said. With this kind of information, planners may be able to identify areas where buildings should be reinforced and take other steps to minimize damage. And disaster officials can identify places most likely to need immediate help after a strong earthquake. The best possible outcome would be to get a series of small earthquakes, around magnitude 3 or 4, popping off within about 30 miles of the array and on all sides of it, so the researchers can view waves coming in from all directions. ``One of the things we're starting to see is that seismic waves don't travel in straight lines from an earthquake to a site,'' lindh said. ``Seismic waves take various kinds of circuitous paths going from one point to another. I, at least, have been mightily surprised simply by the distortion of the wave front.'' what's next? Lindh hopes to start a similar experiment this summer in san francisco and oakland, with about 60 seismometers spaced three kilometers apart. Although there are no big basins underlying those cities, he said, there are hills, which are ``sort of basins upside down.'' and waterfront areas lie on soft sediments, which are known to amplify shaking in an earthquake. If you have suggested topics for this feature, please call us at (408) 920-5993, fax us at (408) 288-8060, send us an e-mail at local@............. or write to the mercury news, 750 ridder park drive, san jose, calif. 95190. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Edward cranswick us geological survey golden, co 80401 usa tel: 303-273-8609 fax: 303-273-8600 -------------------------------------------------------------- sjo (santa clara valley) dense strong motion array 1999 apr 07-23 hensley house, 456 n 3rd. St., San jose, ca 95112 tel: 408-295-2391 fax: 408-298-4676 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Norman Davis WB6SHI Subject: Re: To Ham Radio Operators Date: Sat, 10 Apr 1999 06:20:18 -0700 Looking back through messages I re read this one and was wondering if you guys have had any luck doing this. I have so much RFI from my packet that I have it turned off. I use to be on APRS all the time. > >> PSN >> >> As you may all know, we have just gotten our seismic station setup on >> Dominica. Because of the distance I live from the earthquake zone and >> the unsuitability of my home as a seismometer site, I am looking for an >> alternative to getting my daily data for processing. >> >> My idea is to run a memory resident packet program on the SDR computer >> before running SDR. The program would work in the same manner as its >> telephone counterpart PCANYWHERE. This program would then give me remote >> access to the SDR computer via packet radio. >> >> Does anyone of you ham radio operators on this list know of such a >> program? Your input would be greatly appreciated. >> >> Wayne >> > >Wayne, >Right now I am busy writing some software to send some ELF receiver data >from a remotely located sensor via amateur packet radio. The approach we >are using is to have the remote system perodically send a data file using >the YAPP packet protocol. This is another approach to the communication >problem. I think for your situation the approach you have outlined may be >better. I haven't looked into it too closely but there are a number of >packet radio terminal programs that can be used like a BBS. I think that you >can log onto the remote BBS via packet radio and request directory >information and files be transferred. The big problem as I see it is going >to be getting SDR to work in conjunction with the packet radio program. I >will do some more reading and post some more ideas later. >-- >Jim Hannon >http://soli.inav.net/~jmhannon/ >42,11.90N 91,39.26W >WB0TXL > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > Norman M. Davis WB6SHI Shingle springs, CA mailto:normd@............. http://www.directcon.net/normd/index.htm ICQ: 7192318 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Wayne Abraham J73WA Subject: Re: To Ham Radio Operators Date: Sat, 10 Apr 1999 09:40:25 -0400 Norman Nothing yet. I still make the 70 mile round trip trek to acquire data every 2 or 3 days. Wayne Norman Davis WB6SHI wrote: > Looking back through messages I re read this one and was wondering if you > guys have had any luck doing this. I have so much RFI from my packet that I > have it turned off. I use to be on APRS all the time. > > > -- Wayne Abraham 1430 Rodney Street Portsmouth, Dominica abrahamw@........ http://www.freeyellow.com/members6/dominicapsn/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Francesco Subject: monster quake in central america??????? Date: Sun, 11 Apr 1999 00:11:21 +0200 Anyone have registered a big event off coast of central america (sud of Panama) at 14:52:26.4 with magnitude Ms 8.0 !!!!! This gosth-event is reported by Norsar Array (Norway) and posted on http://www-csem.bruyeres.cea.fr/cgi-bin/ALERT_all_messages.sh?1 European Mediterranean Seismological Center. It's an incredible mistake? Francesco Nucera Italy _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Wayne Abraham J73WA Subject: Re: monster quake in central america??????? Date: Sat, 10 Apr 1999 19:48:19 -0400 Francesco I checked NEIC's Near Realtime Earthquake bulletins, QED bulletins and CNSS databases and have not seen any quake for that time. May either be too early or a mistake. Wayne Francesco wrote: > Anyone have registered a big event off coast of central america (sud of > Panama) at > 14:52:26.4 with magnitude Ms 8.0 !!!!! > > This gosth-event is reported by Norsar Array (Norway) and posted on > http://www-csem.bruyeres.cea.fr/cgi-bin/ALERT_all_messages.sh?1 > European Mediterranean Seismological Center. > > It's an incredible mistake? > > Francesco Nucera Italy > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Wayne Abraham 1430 Rodney Street Portsmouth, Dominica abrahamw@........ http://www.freeyellow.com/members6/dominicapsn/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "John Krempasky" Subject: Re: monster quake in central america??????? Date: Sat, 10 Apr 1999 20:51:42 -0400 http://seismo.ethz.ch/redpuma/redpuma_ami_list.html Red Puma has this as a 7.8 south of Panama. We'll see what the deal is. Interesting. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Charlie Plyler Subject: Re: monster quake in central america??????? Date: Sat, 10 Apr 1999 21:06:50 -0400 According to the "Live seismic server, no major events recorded" http://aslwww.cr.usgs.gov/Seismic_Data/heli.htm Weird one! Charlie Plyler John Krempasky wrote: > http://seismo.ethz.ch/redpuma/redpuma_ami_list.html > > Red Puma has this as a 7.8 south of Panama. > > We'll see what the deal is. Interesting. > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Giacomo" Subject: R: monster quake in central america??????? Date: Sun, 11 Apr 1999 03:13:12 +0200 You excusme but I was reading this inconceivable event really interesting, I want to know information on the event if you it reenter in the norm. Hi and thank you James. Thanks again. -----Messaggio originale----- Da: John Krempasky A: PSN-L Mailing List Data: domenica 11 aprile 1999 2.53 Oggetto: Re: monster quake in central america??????? >http://seismo.ethz.ch/redpuma/redpuma_ami_list.html > >Red Puma has this as a 7.8 south of Panama. > >We'll see what the deal is. Interesting. > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Angel Rodriguez Subject: Re[2]: monster quake in central america??????? Date: Sat, 10 Apr 1999 20:15:53 -0500 Hello, I live in Panama and I wouldn´t need a seismograph to to feel a 7.8, I haven´t felt anything but I will check me record for that time. Angel _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Interesting Article on Silicon Microphones Date: Mon, 12 Apr 1999 11:04:42 -0700 (MST) I saw the following article in "Science" and thought is might be interestin= g to some people in the group. This technology may also find future applicati= ons in seismometry when they get it to work predictably by tuning into lower frequencies... This type of design could also make planetary seismometry f= ar more practical; wouldn't that be fun! I like the thought of recording quak= es or impacts on Mars, Galileo, Europa, Mercury and other solid bodies (comets maybe?). This could solve the many solid/liquid debates. Also ocean-botto= m seismometry could pick up as well, which would considerably improve coverag= e on the Earth. _________________________________________________________________ =20 ACOUSTICS: Miniaturizing the Mike, in Silicon Alexander Hellemans* =20 The microphone is being reincarnated in silicon. At a recent meeting+ in Berlin, several groups reported progress in converting the standard elements of a microphone--a vibrating membrane that picks up the sound and circuits that convert the vibration into an electrical signal--into structures on a silicon chip. Silicon microphones may not yet be as sensitive as conventional microphones, but they will be robust and cheap. "You can make thousands of them on a wafer," says physicist Gerhard Sessler of the Technical University of Darmstadt in Germany. "It is the coming thing," adds acoustic engineer Allan Pierce of Boston University in Massachusetts. =20 Most silicon microphones still rely on vibrating membranes to capture sound, but these membranes are micromachined from silicon and measure just 1 millimeter or so on a side and a micrometer thick. In the type of silicon mike that is closest to commercial production, known as a condenser microphone, the membrane is positioned next to a charged electrode. Together, the electrode and membrane form a capacitor, a structure that can store charge. Its capacitance, or ability to hold charge, depends on the distance between electrode and membrane. As the membrane vibrates in response to sound, the distance changes and so does the capacitance, creating an electrical signal in a circuit connected to the device. =20 In a variation on this theme, the field-effect microphone, the membrane is given an electric charge and positioned near a semiconductor channel that separates two contacts. The channel's ability to carry current varies in an electric field; as the membrane vibrates, it subjects the channel to a varying electric field, modulating the amount of current flowing through it. =20 In early prototypes of condenser and field-effect microphones, the membrane was etched out of one chip and the other part of the device was built on another, and the two were pressed together. At the meeting, Sessler reported a new technique for creating the whole device on a single chip. "On the chip you deposit a so-called 'sacrificial layer' ... and on top of that layer you deposit the membrane," he says. Chemically etching away the sacrificial layer leaves a free-floating membrane anchored to the chip at its edges. =20 Other presentations described microphones in which piezoelectric and piezoresistive materials are deposited on top of the silicon membrane. These materials generate a current or a change in resistance, respectively, in response to changes in pressure. The result is a varying electrical signal as the membrane flexes in response to sound waves. =20 A few microphone designs presented at the meeting translate the vibration into an optical signal rather than an electronic one. The advantage of these designs, explains Sessler, is that optical signals don't interfere with each other via magnetic fields, so large numbers of optical mikes can be packed close together. The optical output can also travel long distances through optical fibers without degrading. "You don't have to preamplify directly at the microphone," says Sessler. =20 In one such device, developed by Sessler's group, the vibration of the membrane deforms an optical waveguide, altering its ability to transmit light. Two other designs pick up vibrations by bouncing a laser off a silicon membrane and recording variations in the reflected signal--a scaled-down version of a Cold War eavesdropping technique that picks up conversations that are taking place inside a room by playing a laser beam off a window. Pierce and his team at Boston have created small portable arrays of over 10,000 tiny microphones of this design connected to a small display device. The result is an acoustic imaging system, which can reconstruct the shape of objects by detecting differences in the arrival time of reflected sound pulses. The team is now developing an "artificial eye" for use underwater that would send out ultrasound pulses and detect reflected waves to distinguish objects as small as 1 millimeter. =20 One of the new designs even shuns the traditional membrane. J=F6rg Sennheiser of Sennheiser Electronic Corp. in Wedemark, Germany, presented a microphone that consists simply of two tiny wires placed close together and heated electrically. The small flows of air molecules generated by sound waves cool the wires. "The temperature difference in the two wires depends directly on the velocity of the air particles," explains Hans-Elias de Bree, who developed the concept several years ago while still a student at Twente University in Enschede, the Netherlands. The microphone, which Sennheiser says could be realized in silicon, cannot respond to sound frequencies any higher than about 10 kilohertz, making it usable for telephones but not for ** high-fidelity recording. But it can stretch down to waves below 20 ** hertz, which are important in seismology. "A pressure microphone simply cannot do this," says de Bree. =20 Although no silicon microphones are yet produced commercially, researchers in the field are bullish about their prospects. In a few years, says Sessler, "nobody will use conventional microphones anymore, only silicon ones." =20 __________________________________________ =20 Volume 284, Number 5412 Issue of 9 Apr 1999, pp. 235 - 237 =A91999 by The American Association for the Advancement of Science. John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ***************************************************************************= *** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: The Design and Performance of a Low-cost Strong-motion Date: Mon, 12 Apr 1999 15:41:53 -0600 (MDT) Because of the possible interest to PSN members, I've put a copy of John Evans' USGS Open-file Report on The Design and Performance of a Low-cost Strong-motion Sensor onto the following web page: http://geohazards.cr.usgs.gov/evans/ofr_98_109.html This address will work for the next few weeks, but eventually John E. will be moving the report to a USGS web server in Menlo Park. The bulk of the report is in PDF format; free readers are available here: http://www.adobe.com/prodindex/acrobat/readstep.html in case you don't have one already. Cheers, JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "jim E O'Donnell" Subject: Re: Accelerometers or Velocity meters to Record Local Earthquakes? Date: Mon, 12 Apr 1999 15:51:13 -0700 Sean, STM @ SLU Thanks for hosing me down, you jogged my memory real good, and brought back things I knew, but had forgotten, not to mention you told me some things I didn't know. The comment on 25-50 Hz signals coming from an earthquake is rather interesting (can you give me a ref. on this?) as occasionally, twice now, in the last year, people in Boulder City, NV, right outside Las Vegas, have told me they heard and felt very small eq's, M=2.0-3. My hearing is not that good, but I can still feel the small ones. Also have reliable eyewitnesses who saw surface waves, Rayleigh, close to the epicenter, 3 & 6 km. away, from a BC, M=3.9, depth 10km's in Feb, 1988; also had a M=3.7 in July 1988, soo the USGS finally deployed, and recorded >200 aftershocks in 6 weeks in Sept & Oct., 1988. Geophones: How would I do, if I used some hori. & vert. geophones, no doubt velocity meters, and recorded for a month or so in the field very close to the fault zones, say 5-20 kms from the hypocenter, with the hope of recording very small, local activity, M<2? I am assuming M=2 or less can't be felt by humans. Have some Z's @ 14 Hz, I just bought from surplus, and we have some good H's @ 2 Hz at UNLV's Engineering Geophysics Laboratory. Could you recommend a good geophone, which might do the job? STM-8: Real interested in your STM-8 drawings, will send lots of stamps, but need complete address for SLU? DSVS: BTW, 11 years ago I was managing a DOE program here at the NTS, called Deployable Seismic Verification System, DSVS, which the National Lab's were involved in. We were developing a real-time, satellite system, to go to the USSR for Nuclear Test Ban Treaty Monitoring. We had the long period KS54000 and a short period S-3, both borehole of course, but both mechanical seismometers from the 60's or 70's, and I recall the S-3 was similar or was the S-13 in borehole mode. I wanted a truly single FB, BB portable system that would record in borehole or pier that would replace both the KS and S-3. That's when we discovered Cansun Mustafa Guralp, CMG in England. We had him develop the CMG-3T, a state of the art package of 3 components that would be a borehole or pier seismometer. The seismometer consultants we had were Peter Rodgers, who wrote the eq's of motion for the KS's, the McEvil, and of course Fuzzy. If I knew then, what I know now, STM would have been on board too. Accelerometers or Velocity meters: After all that, I still don't know why some FB seismometers are truly velocity meters or truly accelerometers? I know you can integrate or take the differential quite easily, even inside the instrument but that is different than recording initially with one or the other mode? For the sake of clarification, one is an inherent accelerometer, while the other you can derive the acceleration from the velocity, but you also derive or enhance noise with it. Can you help me out here, for example the STM-8 is a velocity meter while Roger's Hi-Q is an accelerometer? Since UNLV is interested in recording low magnitude, local earthquakes, 5-20 km's away, which should be rich in high frequencies, wouldn't we be better off with an accelerometer which enhances the high frequency range? ADXL202 chips, 2 axis strong motion accelerometers: Incidentally, I just got delivery of 2 ADXL202 chips, 2 axis strong motion accelerometers, from Analog Devices. I am wondering how to configure them, wire them up, wonder if anybody has done that yet? How about it Larry? Best Regards, Jim @ UNLV _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: The Design and Performance of a Low-cost Strong-motion Date: Mon, 12 Apr 1999 16:48:05 -0700 I called EG&G sensor group today to find out the cost for one sensor. The +-2 g version in single quantities is $108.00 (the same cost as a GPS receiver, but more about that in an other email) . They have a minimum order of $200.00, so you need to buy two and they won't give out samples. And it will take 8 weeks to get some, since they are not in stock. -Larry Cochrane At 03:41 PM 4/12/99 -0600, you wrote: > >Because of the possible interest to PSN members, >I've put a copy of John Evans' USGS Open-file Report on >The Design and Performance of a Low-cost Strong-motion >Sensor onto the following web page: > >http://geohazards.cr.usgs.gov/evans/ofr_98_109.html > >This address will work for the next few weeks, but >eventually John E. will be moving the report to a USGS web >server in Menlo Park. The bulk of the report is in PDF format; >free readers are available here: > >http://www.adobe.com/prodindex/acrobat/readstep.html > >in case you don't have one already. > >Cheers, > >JCLahr > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Angel Rodriguez Subject: Garden gate Lehman with wire in tension pivot Date: Mon, 12 Apr 1999 19:24:12 -0500 Hi, I´m builing a lehman garden gate type horizontal and am using a wire in tension pivot for the boom and two wires on the mass. It look pretty good and I would like to get some commenst and suggestions from the list members. I have posted some photos at www.barriles.com/gardengate I would really appreciate any comments. thanks Angel _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: VBB vertical Date: Mon, 12 Apr 1999 21:00:59 -0700 Sean Thomas & Brett I rearranged a small "Vbb" vertical I had been working on to incorporate the tapeing blade(3"x12"x0.018"). It has a boom of 12" length and a mass of ~1kg. I am using .001" shim stock for the flexures. The interesting thing is, the stable configuration is with the tapeing blade bottom support closer to the support column than the upper flexural support rather than the opposite. I get a ~3.5 sec period with the bottom 4.5" from the support and the top 5" from the support. I have noticed in the past that changing the flexurals from 0.005" to 0.001" makes a considerable difference in the mechanical properties of the system. Maybe this is unimportant in the system with feedback. Input? regards Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Stephen Caruso" Subject: tornados and seismo Date: Tue, 13 Apr 1999 00:00:35 -0400 Has anybody ever followed up on the seismic interpretation of a tornado? We have a network of 14 seismos in Ohio now. Is there a way to interpret this data? Perhaps an excel file or PIE chart config? Stephen Caruso _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: meredith lamb Subject: Comments on a garden gate lehman Date: Mon, 12 Apr 1999 22:00:57 -0600 Angel Rodriguez, Congratulations on your web site: http://www.barriles.com/gardengate Its always nice to see a new site, and the pictures were all pretty good. I believe you are the first amateur to make use of the tension wire boom mast support structure, that I know of. Its a common feature on the old commercial Sprengnether horizontals.....but it does its job very well. Do have two suggestions for your seismo. First, the front of the seismo should have two screws, and an increased support bar underneath and wider spacing between the screws.....the mass may topple. Kind of a reverse of your set screw tabs as is.....or put the mast where the one setscrew tab is, a reversal so too speak. The second suggestion is for you to increase the plate strength....maybe running angles on top or underneath the plate lengthwise. The 1/4" thick plate maybe "bowing" in movement with the mass on any big quake could experience; and the weight of the mass could force the plate to bow down just by the weight over time. Presume the "spokes" on your lead mass aren't magnetic? If they are and you use magnets, it will influence the mass of course. They look vaguely golden in color....so maybe they are brass? Perhaps on the pivot I would contemplate a thicker diameter bar or "spoke", to alleviate any possible bending from the mass weight. A solid rod of about anything would help. Instead of wrapping it around it, drill a hole for the wire to run through, and drill and tap another hole for a setscrew to anchor the wire. What are you planning to use for the sensor and damping? Yes..., I'am jumping ahead....ha. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: More on GPS timing receivers Date: Mon, 12 Apr 1999 23:23:42 -0700 Hi Everyone, A few weeks ago I reported that the cost of the ONCORE GPS that can be used with my SDR program, had gone down from $199.00 to $171.00. This is for the UT+ version of the ONCORE receiver with a backup battery. After looking at the different versions of the receiver in there catalog, I called Synergy Systems to find out what the difference was between them. It turns out that the GT+ version is perfect for our application and only costs $108.00 in single quantities. The main difference between the UT and the GT is the accuracy of the 1 PPS timing signal. The UT has an accuracy of ~45 ns (as in nanosecond) verses ~500 ns for the GT version. Since SDR uses a 1 millisecond interrupt for timing, there is no need for accuracy below 1 ms from the timing reference. Nor, IMHO, does one need better then a few ms accuracy for seismic work. The $108.00 price does not include a backup battery. If needed, one can be added as part of the external interface need to use the receiver. Without a battery, it takes longer before accurate timing is established, since information needs to be download from the satellites each time the power is turned on. It looks like it takes about 10-15 minutes from a cold power up before good timing information comes out of the receiver. With a battery the receiver can save needed information and also keep track of UTC time until power is reapplied. This means that a GPS system can be purchased for under $130.00, if you use Pete Ouellette's GPS antenna (cost is $19.95 see http://www.sawcenter.com/gpsant.htm) and make your own interface board. The interface board needs to supply 5 volts dc to the receiver and take the TTL level serial in and output signal and convert them into standard RS-232 voltage levels. I also like to buffer the 1 PPS output with a 74LS04 TTL inverter (for SDR you need to run the signal through two of the inverters in the chip so that the polarity will be the same as the input) to protect the GPS receiver. With the cost being so low I went ahead and bought one for my own use. WWV works great for me but, I just could'nt resist it.... I also order one of Pete's antennas and will report back to the group on how well it works compared to the $52.00 Motorola antenna. I'm thinking of selling a complete GPS receiver as an option with my A/D card / SDR system. This would include a tested GPS receiver, antenna and interface board. The cost would be around $190.00. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Taber Subject: Database trial Date: Tue, 13 Apr 1999 18:21:25 +1200 (NZST) As some of you are aware, we have been slowly setting up a network of short-period seismographs at schools in New Zealand using Larry's amplifiers. One part of the project has been the development of an online database so schools can easily share data. We think (hope) the database program is ready but it would greatly benefit from testing by PSN members before we release it to the schools. If you have the time we would appreciate if you could try sending and extracting some data from the database to see if you can find anything that doesn't work properly or needs to be better explained. The database pages start at http://scott.geo.vuw.ac.nz:8001/ Once they have been beta tested they will be linked to the main Quake Trackers pages (www.quaketrackers.ac.nz). Right now there is a dummy link from the main pages. The plan for the database is to include data primarily from earthquakes that occur in or near NZ, but for the purposes of the test, we would like to get recordings from anywhere. We have put in some of the school recordings and some of Dave Nelson's recordings and a few others I picked up from Larry's site to start so there is some data if you search the database right now. Not all the NZ school data has all the proper header information yet, and some of the times are wrong. For example the St. Mary's Wtgn clock appears to be 1 hour off. We will have stations with GPS timing but the first ones are just being installed this week. As you will see, if you aren't registered in the database, your first attempt to send data to the database will fail, but I should automatically get a copy of your PSN header and will add you to the list. This is so that we can keep track of who is sending us data. Any non-PSN format data should simply be rejected. Feel free to try to abuse the database in any way because I'm sure the students will, and it would be best to find out now what we need to make more robust. Please send me (or post to the list) any comments and suggestions as well as any problems you encounter. Our target audience is high school students. Regards, John Taber John Taber School of Earth Sciences, Victoria University John.Taber@.............. Box, 600, Wellington, New Zealand phone: +64-4-472-1000 fax: +64-4-495-5186 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Re: VBB vertical Date: Tue, 13 Apr 1999 08:31:17 -0400 Barry, I agree that with feedback, the flexures shouldn't have a first-order effect on the way the instrument performs. With some configurations it may be that the thinner flexures would make it slightly easier for the loop to maintain control of the boom at extremely low frequencies.... that is if there's no temperature or barometer changes and no spring "creep", etc.. Those effects shouldn't get any better (or any worse) with feedback. One thought; since you've gone to really thin flexures, when the spring was angling back toward the hinge, you're likely to have the horizontal flexures starting to buckle. That could make the performance pretty uncertain. With the spring angled the other way, as you now have it, the flexures will be in tension and should be working fine. Wonder if that might be a piece of what you're seeing? As I understand it, you were looking for a stable configuration without feedback. What I'd been working on was to find an unstable, or to be precise, a neutrally stable configuration and then count on the feedback to keep it centered. I'd be interested in putting your dimensions into my program and seeing what comes out. The math still hasn't had much testing with real numbers. If you (or anyone else) want me to try that, take a look at the figure in the "vertgeom.pdf" file and send me the approximate dimensions you're using, including the spring opening and its flexure lengths, as well as the locations (vert & horiz) of the mass, and of both spring attachment points with respect to the beam hinge or with respect to points I can relate to the hinge. I'm going to be in CA for a week beginning the 19th, so might not get to it until I get back, but I'd really like to see if my results are anywhere near what your'e seeing. I'll leave the real-world part of this to S-T. So far, my only seismo. is a computer model. Regards, Brett At 09:00 PM 4/12/99 -0700, you wrote: >Sean Thomas & Brett > I rearranged a small "Vbb" vertical I had been working on to >incorporate the tapeing blade(3"x12"x0.018"). It has a boom of 12" >length and a mass of ~1kg. I am using .001" shim stock for the flexures. >The interesting thing is, the stable configuration is with the tapeing >blade bottom support closer to the support column than the upper >flexural support rather than the opposite. I get a ~3.5 sec period with >the bottom 4.5" from the support and the top 5" from the support. I have >noticed in the past that changing the flexurals from 0.005" to 0.001" >makes a considerable difference in the mechanical properties of the >system. Maybe this is unimportant in the system with feedback. Input? >regards > Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "James M Hannon" Subject: Re: More on GPS timing receivers Date: Tue, 13 Apr 1999 07:58:34 -0500 Larry, A couple of comments and a question. It seems that it would be easy to mount the GPS receiver on your card and run the antenna coax to a connector mounted on the L bracket. At least on my computer some of the serial ports are on the motherboard and one could run a ribbon from the serial connector to your card internal to the computer case. When you use the GPS timing option, how important is the stability of the oscillator? If it is still useful to have a accurate and stable oscillator it would not be difficult to phase lock an oscillator to the 1 pps output of the GPS. Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: Database trial Date: Tue, 13 Apr 1999 10:39:18 -0600 (MDT) Hi John, Your web site is looking good! I was able to download an event and look at it with WinQuake. The hardware page doesn't tell what sensor is being used by the NZ schools. On this page: http://www.quaketrackers.ac.nz/sug.reading.html the link to: Caught in the Crunch: Earthquakes and Volcanoes in New Zealand, 1996. is broken. On this page: http://www.quaketrackers.ac.nz/curr/eqmag.htm the equations did not show up. JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Re: More on GPS timing receivers Date: Mon, 12 Apr 1999 23:42:49 -0700 James M Hannon wrote: > my computer some of the serial ports are on the motherboard and one could > run a ribbon from the serial connector to your card internal to the > computer case. I'd just like to comment/rant/buzz in also: ATX motherboards (the new style that most PII, PIII, Celeron and some K6 CPUs now use) have the serial ports attached to the motherboard directly. You can still buy those cheap ISA cards with serial ports on them. Microsoft want's to push serial ports into legacy land along with parallel ports and the ISA bus, so this might be a little more expensive in the future. USB to serial port adapters or PCI serial port cards will be options. Of course the ADC card is ISA also. And then there was an industry group trying to organize a much faster and wider PCI bus without Intel. And all of those little fixes probably won't work with Windows 2000 or whatever they decide to call it. Some things about the computer industry are just sad. On the up side I dug up my geophone and moved it back into the house since I wasn't getting anything outside. It was very nice and dry with the zeolite on top (thanks for the suggestions) and it still works. I might try keeping it in the closet for a while, there's not really any good place to put it. :( I upgraded my SDR computer from the 486 to the P166 and it runs much, much faster now. Noise didn't go up at all on the ADC. I upgraded my WinQuake compupter to a PII. The Linux device driver is sort of stalled at this point. I've even offered money for help. Linux kernel 2.2.x came out and I'm kind of worried that it won't work with that even if it works with 2.0.x. Those GPS prices are tempting aren't they? ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Angel Rodriguez Subject: Re: Comments on a garden gate lehman Date: Tue, 13 Apr 1999 13:48:48 -0500 Hello Meredith, Monday, April 12, 1999, 11:00:57 PM, you wrote: Thanks for your suggestions. The base plate is really a base channel whit sides which are about 2inche high and 1/4 inch thick. It´s probalby the stoutest part of the thing, but I might put a brace on it anyway since it´s so easy. The pins in the mass area stainless. I so plan to put some sort of stops so the mass does not get away from me. I have replace the back pin to a rod 3/16th stainless (I had one) I tried drilling the smaller rod with no success this new rod I may well get a hole into. And no you are not jumping ahead, the dampening has always been hard for me. I use oil on my tow other lehmans and tried resitive only dampening on one of them and got no where. I will be using Larry´s magnet and coil (you can see them on lhis page) Do you think that I can dampen that mass with that coil and magnet? I could really use any advise from everyone on that subject. Where I´m headed with this is to build a set of three long preiod device so that I can then calculate azimuth and locate regional and distant event. I can do it now for local event. It´s fun to make a map and see all the local event ploted. I really do appreciate the comments. Warmly, angel ml> Do have two suggestions for your seismo. First, the front of the seismo ml> should have two screws, and an increased support bar underneath and ml> wider spacing between the screws.....the mass may topple. Kind of a ml> reverse of your set screw tabs as is.....or put the mast where the one ml> setscrew tab is, a reversal so too speak. The second suggestion is for ml> you to increase the plate strength....maybe running angles on top or ml> underneath the plate lengthwise. The 1/4" thick plate maybe "bowing" in ml> movement with the mass on any big quake could experience; and the ml> weight of the mass could force the plate to bow down just by the weight ml> over time. ml> Presume the "spokes" on your lead mass aren't magnetic? If they ml> are and you use magnets, it will influence the mass of course. They ml> look vaguely golden in color....so maybe they are brass? ml> Perhaps on the pivot I would contemplate a thicker diameter bar ml> or "spoke", to alleviate any possible bending from the mass weight. ml> A solid rod of about anything would help. Instead of wrapping it ml> around it, drill a hole for the wire to run through, and drill and ml> tap another hole for a setscrew to anchor the wire. ml> What are you planning to use for the sensor and damping? Yes..., ml> I'am jumping ahead....ha. ml> Meredith Lamb ml> _____________________________________________________________________ ml> Public Seismic Network Mailing List (PSN-L) ml> To leave this list email listserver@.............. with the body of the ml> message: leave PSN-L Best regards, Angel mailto:angel@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Re: The Design and Performance of a Low-cost Strong-motion Date: Tue, 13 Apr 1999 10:06:45 -0700 John E.'s article on the low-cost strong-motion seismometer is interesting, worthwile and seems more than valid from a technical standpoint. However, as a general rule, USGS folks are good scientists and bad businessmen. It isn't economically valid to add up the cost of the parts and compare them to the retail price of a competive product. First of all, parts and labor don't build a system. On top of that, you need someone to buy the parts, a computer to keep track of them, somebody to open the boxes and put them in the stock room, somebody else to pull them from stock into kits, somebody to manage all these people, and space and utilities where you work. The way this is usually handled is to add overhead onto the actual assembly and test labor, so your assembly labor costs end up to be $50 to $75 an hour (or more), not the $10 or $15 you pay the basic worker. Alternatively, you can have the whole thing built outside, like HP and IBM do with personal computers, but there are other costs associated with that and you have to address volume issues and transaction costs. So, let's say we can build the accelerometer for $800 in parts and labor (a guess based on experience). We call this number the "cost of goods sold" or COGS. What else does it take to run a business like this? Well certainly R&D. A reasonable number for a specialized high tech business like this would be 10% of sales. We're not talking huge volumes to amortize the engineers. Marketing of course. Gotta pay for those booths at the AGU meeting, run some ads in the geophysics magazine, print those nice data sheets, pay folks to write the orders and talk on the phone. The salesmen are generally highly skilled professionals that know the science as well as the business aspects or the scientists won't treat them with respect. Figure about 15% There's a thing called G&A, or general and administrative. That's the accountants, the unallocated floor space, the human resources folks, insurance, payroll processing, the general manager's salary, interest on the money borowed to run the business, yada, yada, yada... Another 15% How about some profit, possibly a dirty word but the engine that drives the free enterprise system. Let's add some of these up. COGS 50% R&D 10% Mkt 15% G&A 15% PBT 10% (profit before tax) Taxes 5% PAT 5% Not much of a profit, 5%. And our accelerometer is now selling for $1600. It's still cheaper than the Kinemetrics unit at $2700, but the difference is not "night and day". It suggests that Kinemetrics might take a look at this design. However, it's not that simple. First of all, things go wrong. Costs always come in higher than they are supposed to, and it's prudent business to look for a selling price of three times what it ought to cost, and 2.5X is a much more comfortable cushion than 2X. If you don't work at 20% OP, you won't get 10%. How about a sole source vendor? I worked for EG&G for over 15 years. They are fine businessmen and if this thing doesn't make money, they will discontinue it. As for buying 10,000 pieces, will the USGS write an order for 10,000 accelerometers? That will get the price down just as it did with SMA-1's many years ago. Folks, I have fought the cost-of-goods problem for a long time. Those overhead costs are real. When you take time to order parts, and pay the bills, and set aside a workshop, or run to the hardware store, that's overhead. That's fine when it's your hobby, but when a business does it, somebody has to pay for it. Somebody is you the customer. Someone once told be that a "fair" price is one that's high enough to allow you to stay in business to continue to serve the customer. There are good reasons why geophysical gear costs so much. I don't mean to jump on John E. or fault his science. It's just that the cost projections glared out at me and I thought I would speak up for the manufacturers. -- Doug Crice web site http://www.georadar.com GeoRadar Inc. e-mail dcrice@............ 19623 Via Escuela Drive phone 408-867-3792 Saratoga, CA 95070 USA fax 408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Taber Subject: Re: Database trial Date: Wed, 14 Apr 1999 09:31:06 +1200 (NZST) Hi John, Thanks for the comments. I've fixed the broken links you found (which also led me to a few others) and I agree we definately need a page that describes the hardware at each school. The hardware is about to change at the first few schools so I guess we need a historical list of the sensors and timing accuracy for each site (just like a real network!). Cheers, John _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: The Design and Performance of a Low-cost Strong-motion Date: Tue, 13 Apr 1999 15:50:34 -0600 (MDT) Doug, Thanks for the feedback on the real cost of manufacturing a product. This is particularly true for items that do not have a mass market. For example, we could post the schematics and parts list for a color TV set. By the time one purchased the parts in quantity 1, and allowing nothing for the time spent to purchase and build the TV, the cost would be way more the going down to the store and getting a new TV! However, geophysical instruments are generally not in this category. The cost of the parts alone is usually much less than the cost of a finished product. So, if you're an interested amateur, you can put together a system that functions OK for much less than a commercial version would cost. That doesn't mean that you could make money selling this product, because you chalk your time up to a learning, and hopefully fun, experience. From the price that Larry found for the accelerometers used by John E's unit, this exact design is out of the question for my home budget. However, I think that his discussion of design goals and some circuit ideas may be applicable to other projects that some of the PSN members are interested in undertaking. Cheers, JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Taber Subject: database additions Date: Wed, 14 Apr 1999 09:53:29 +1200 (NZST) Thanks to various PSN member's attempts to use our database I've discovered another bug. I get sent the header of unregistered files which allows me to add them to the list, but I don't get the email address, which means I can't notify the sender once the station has been added, and I don't get the 3 letter station code. If you get a response saying your site isn't registered yet, could you please send me a quick email (or click on the QuakeTrackers email button) with your station code so I can let you know when your site has been added. So far I have added CGP Hayward Ca USGS Thanks, John Taber _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: JIm Hannon Subject: Re: More on GPS timing receivers Date: Tue, 13 Apr 1999 20:53:48 -0500 Greg wrote: > > Of course the ADC card is ISA also. And then there was an > industry group trying to organize a much faster and wider PCI bus > without Intel. And all of those little fixes probably won't work with > Windows 2000 or whatever they decide to call it. Some things about the > computer industry are just sad. It probably won't be long before the ISA slot disappears from PCs. When that happens things are going to get a bit more complicated for the casual board designer. The PCI bus is no picnic to design a card for and the software is not easy either. Windows 2000 will probably use the WDM (windows driver model) for its device drivers the same as win 98 and similar to NT. I have written a couple of NT and Win 98 device drivers and they have a real steep learning curve. I am thinking that the best way to go for simple interfaces to the newer PCs is going to be USB devices. There is still a device driver to write but the hardware interface is not too bad given all the USB chips you can buy. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: VBB vertical Date: Tue, 13 Apr 1999 22:23:31 -0700 Brett Thanks for the comments. Brett Nordgren wrote: > Barry, > > One thought; since you've gone to really thin flexures, when the spring was > angling back toward the hinge, you're likely to have the horizontal > flexures starting to buckle. That could make the performance pretty > uncertain. With the spring angled the other way, as you now have it, the > flexures will be in tension and should be working fine. Wonder if that > might be a piece of what you're seeing? > Yes I was thinking about that when I saw the response. I think I will reinstall the two horizontal flexures to use 0.005" phosphor bronze shims. I think buckling can also occur with transverse movement of the mass , which causes one of the two flexures to go into compression . > > As I understand it, you were looking for a stable configuration without > feedback. What I'd been working on was to find an unstable, or to be > precise, a neutrally stable configuration and then count on the feedback to > keep it centered. I'd be interested in putting your dimensions into my > program and seeing what comes out. The math still hasn't had much testing > with real numbers. > > I wish I knew what the mechanism was for the possible relaxation of the steel. I realize many materials creep but I wasn't aware that steel crept at this stress level. I thought it would still be elastic. As soon as I get a working model I'll send you the parameters. Regards Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: More on GPS timing receivers Date: Tue, 13 Apr 1999 22:35:05 -0700 Hi Greg I have been seriously thinking of "Single Board Computers" on a passive backplane. They are inexpensive and can be bought in energy efficient models. Most are 8 bit but there are 386EX and above models which are plenty fast for our sampling rates. Just a thought... Barry Greg wrote: > James M Hannon wrote: > > > my computer some of the serial ports are on the motherboard and one could > > run a ribbon from the serial connector to your card internal to the > > computer case. > > I'd just like to comment/rant/buzz in also: > ATX motherboards (the new style that most PII, PIII, Celeron and some K6 > CPUs now use) have the serial ports attached to the motherboard > directly. You can still buy those cheap ISA cards with serial ports on > them. Microsoft want's to push serial ports into legacy land along with > parallel ports and the ISA bus, so this might be a little more expensive > in the future. USB to serial port adapters or PCI serial port cards will > be options. Of course the ADC card is ISA also. And then there was an > industry group trying to organize a much faster and wider PCI bus > without Intel. And all of those little fixes probably won't work with > Windows 2000 or whatever they decide to call it. Some things about the > computer industry are just sad. > > On the up side I dug up my geophone and moved it back into the house > since I wasn't getting anything outside. It was very nice and dry with > the zeolite on top (thanks for the suggestions) and it still works. I > might try keeping it in the closet for a while, there's not really any > good place to put it. :( I upgraded my SDR computer from the 486 to the > P166 and it runs much, much faster now. Noise didn't go up at all on the > ADC. I upgraded my WinQuake compupter to a PII. The Linux device driver > is sort of stalled at this point. I've even offered money for help. > Linux kernel 2.2.x came out and I'm kind of worried that it won't work > with that even if it works with 2.0.x. > > Those GPS prices are tempting aren't they? > > ,Greg > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: More on GPS timing receivers Date: Tue, 13 Apr 1999 23:40:57 -0700 At 07:58 AM 4/13/99 -0500, Jim Hannon wrote: > > >Larry, >When you use the GPS timing option, how important is the stability of the >oscillator? If it is still useful to have a accurate and stable oscillator >it would not be difficult to phase lock an oscillator to the 1 pps output >of the GPS. > > >Jim Hannon No need for this... SDR uses the time information from the time reference (GPS, WWV or WWVB) to compensate from any frequency offset from the ideal 4.0Mhz oscillator on my A/D card (or the PC-Labs A/D card that can also be used with SDR). If the frequency is a little high, SDR subtracts time by dropping one 1 ms at the needed interval to make it look like the osc. is at 4.0 Mhz. If the osc. is a little low it adds time... -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Re: VBB vertical Date: Wed, 14 Apr 1999 09:25:04 -0400 Barry, There might be a couple of other solutions to the very thin flexure buckling problem, though I'm sure they all create some construction difficulties and may not turn out to be practical. You could flip the two flexure mounting angles so that the top one is farther from the mass than the lower one. That way the horizontal flexure would be in tension when the main spring is angled the usual way, top closer to the hinge. In the present design, you'd need to cut a small notch in the upper mount, for the beam to cross over. That doesn't help though with your large horizontal inertial forces. Don't really think that's a significant problem, unless you're expecting strong-motion type accelerations. Another approach could be to reposition the flexure mounting angles, rotated by about 45 degrees so that both flexures were sharing a good portion of the main spring load. That should keep them both well in tension. No idea how to implement that though. It doesn't look easy. I think the previous approach is more practical. Regarding creep. The main problem is that a VBB instrument is just incredibly sensitive. You can observe effects that could be totally ignored in most other applications. From what I have read, you need to consider two areas. Initial creep begins when the spring is first put under stress and gradually slows down over a period of days? weeks? months? years?. I think it was Karl who had suggested first bending the spring and baking it under stress in an oven for a few hours. That would be aimed at getting the initial creep over with, as creep is enormously accelerated by temperature. After that, you supposedly get into a region of steady very slow creep. I see numbers ranging from 30% to 50% of max rated stress being presented as the levels below which creep may be considered to be negligible. Lower stress implies using a thinner spring relative to its length (along with lower mass) I imagine with the sensitivity of the VBB instrument you're always going to have to live with some creep and do as Sean-Thomas has done and provide for occasional mechanical re-zeroing. It is possible that the coil-driving capability at DC could beefed up sufficiently to let it handle the creep over a longer time period, though that might possibly require some tinkering with the loop. When you mechanically re-zero, you are essentially becoming part of the position feedback yourself, acting non-linearly at a very low frequency (1/months), and my thought was that given sufficient force capability and DC loop gain, the main feedback could be allowed to directly take on more of that itself. In any case, the velocity signal wouldn't be showing the creep as it should be too slow to make an observable output. There may be good reasons why this approach won't work. Am still looking at it. Good luck with the experimenting. Brett At 10:23 PM 4/13/99 -0700, you wrote: >Brett > Thanks for the comments. >Yes I was thinking about that when I saw the response. I think I will reinstall >the two horizontal flexures to use 0.005" phosphor bronze shims. I think >buckling can also occur with transverse movement of the mass , which causes one >of the two flexures to go into compression . > >I wish I knew what the mechanism was for the possible relaxation of the steel. >I realize many materials creep but I wasn't aware that steel crept at this >stress level. I thought it would still be elastic. > >As soon as I get a working model I'll send you the parameters. > >Regards >Barry > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: VBB vertical Date: Wed, 14 Apr 1999 09:08:09 -0700 Brett, Barry, and others -- An approach I forsee is much as Brett described -- have the integrator portion of the feedback compensate for at least some of the creep. This goes along with another similar problem (maybe larger), temperature compensation. Even with bimetal springs for compensation, there will still be some left over to deal with. I think it should be possible to insulate and temperature control the enclosure so that creep and the rate of spring force change due to temperature are substantially below the output bandwidth. If this is the case, the integrated feedback path should take care of it, provided it has enough force at its disposal to do the job. Increasing the amount of integrator feedback and its time constant (or some other variation) may accomplish that, or perhaps including another much slower integrator path with more range. However, it probably comes at the expense of noise due to coupling in more electronic noise as feedback force. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... At 09:25 AM 4/14/99 -0400, you wrote: > Barry, >It is possible that the >coil-driving capability at DC could beefed up sufficiently to let it handle >the creep over a longer time period, though that might possibly require >some tinkering with the loop. When you mechanically re-zero, you are >essentially becoming part of the position feedback yourself, acting >non-linearly at a very low frequency (1/months), and my thought was that >given sufficient force capability and DC loop gain, the main feedback could >be allowed to directly take on more of that itself. In any case, the >velocity signal wouldn't be showing the creep as it should be too slow to >make an observable output. There may be good reasons why this approach >won't work. Am still looking at it. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rex Klopfenstein, Jr." Subject: VBB Schematic Questions Date: Wed, 14 Apr 1999 19:34:05 -0400 Sean I have been looking at your revised schematics and I have several questions. First, on the "Schematic of the Electronics and Control Box": Where did you find the resistors that are listed for the Rp and RI ranges. Did you make these up using multiple resistors? Did you leave out the 'gain set' resistor on your unit? This is the resistor shown in series with the High Pass capacitor on the "Quad Amplifier" schematic at the 'top terminal strip'. I am assuming that the rotary switch has all the gangs connected to the same shaft? Second, on the "Quad Amplifier" schematic: What is the value of the resistor shown on the input of A2 in the high pass amplifiers portion of the circuit. -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Jim Esler" Subject: Re: The Design and Performance of a Low-cost Strong-motion Date: Tue, 13 Apr 1999 19:19:32 -0500 I saw the comments on for a strong motion low-cost strong-motion seismometer, and thought I would throw my 2 cents in. I am currently finishing a design for a seismograph detector using a 24bit ADC and a single chip computer. The sample rate is fixed at 10 HZ, LSB ~ 1 uv. The bipolar ADC works from a single sided power supply (I will steal power from the PC) and the processor sends the data to my PC via RS-232. The current rev is on a bread board - and I will be migrating to a 3/4 X 2 inch circuit card next month. The ADC/Microprocessor and a 30,000 turn coil will fit in a 1 X 3 inch capped copper tube. Writing the code for the micro was easy - reading the manual for the ADC was hard. I have about 100 +-2 g micro-machined accels. I am planning on making my ADC/Microprocessor card accept either a coil, an accel or the coil I am winding like the one described by Anthony Fraser-Smith in Am Scientific. I am also about 3/4 done writing an integrated version of emon and a seismogram viewer. The current rev. will now notify me of an earthquake via pager. Transmitting the length of the event in seconds numerically instead of a phone #. I wish Winquake could read 24 bit ascii data.... I already have one system sold as soon as I have the circuit card designed - a buddy has been hanging a digital multimeter to his metal barn roof. When a storm cloud passes over he is seeing a 6 volt charge built up on the roof. He wants to modify my data recorder to monitor the roof. Jim Esler jimesler@............. -----Original Message----- From: Doug Crice To: PSN-L Mailing List Date: Tuesday, April 13, 1999 3:47 PM Subject: Re: The Design and Performance of a Low-cost Strong-motion >John E.'s article on the low-cost strong-motion seismometer is >interesting, worthwile and seems more than valid from a technical >standpoint. > >However, as a general rule, USGS folks are good scientists and bad >businessmen. It isn't economically valid to add up the cost of the parts >and compare them to the retail price of a competive product. > >First of all, parts and labor don't build a system. On top of that, you >need someone to buy the parts, a computer to keep track of them, >somebody to open the boxes and put them in the stock room, somebody else >to pull them from stock into kits, somebody to manage all these people, >and space and utilities where you work. The way this is usually handled >is to add overhead onto the actual assembly and test labor, so your >assembly labor costs end up to be $50 to $75 an hour (or more), not the >$10 or $15 you pay the basic worker. Alternatively, you can have the >whole thing built outside, like HP and IBM do with personal computers, >but there are other costs associated with that and you have to address >volume issues and transaction costs. > >So, let's say we can build the accelerometer for $800 in parts and labor >(a guess based on experience). We call this number the "cost of goods >sold" or COGS. What else does it take to run a business like this? > >Well certainly R&D. A reasonable number for a specialized high tech >business like this would be 10% of sales. We're not talking huge >volumes to amortize the engineers. > >Marketing of course. Gotta pay for those booths at the AGU meeting, run >some ads in the geophysics magazine, print those nice data sheets, pay >folks to write the orders and talk on the phone. The salesmen are >generally highly skilled professionals that know the science as well as >the business aspects or the scientists won't treat them with respect. >Figure about 15% > >There's a thing called G&A, or general and administrative. That's the >accountants, the unallocated floor space, the human resources folks, >insurance, payroll processing, the general manager's salary, interest on >the money borowed to run the business, yada, yada, yada... Another 15% > >How about some profit, possibly a dirty word but the engine that drives >the free enterprise system. Let's add some of these up. > >COGS 50% >R&D 10% >Mkt 15% >G&A 15% >PBT 10% (profit before tax) >Taxes 5% >PAT 5% > >Not much of a profit, 5%. And our accelerometer is now selling for >$1600. It's still cheaper than the Kinemetrics unit at $2700, but the >difference is not "night and day". It suggests that Kinemetrics might >take a look at this design. However, it's not that simple. First of >all, things go wrong. Costs always come in higher than they are >supposed to, and it's prudent business to look for a selling price of >three times what it ought to cost, and 2.5X is a much more comfortable >cushion than 2X. If you don't work at 20% OP, you won't get 10%. > >How about a sole source vendor? I worked for EG&G for over 15 years. >They are fine businessmen and if this thing doesn't make money, they >will discontinue it. As for buying 10,000 pieces, will the USGS write >an order for 10,000 accelerometers? That will get the price down just as >it did with SMA-1's many years ago. > >Folks, I have fought the cost-of-goods problem for a long time. Those >overhead costs are real. When you take time to order parts, and pay the >bills, and set aside a workshop, or run to the hardware store, that's >overhead. That's fine when it's your hobby, but when a business does >it, somebody has to pay for it. Somebody is you the customer. > >Someone once told be that a "fair" price is one that's high enough to >allow you to stay in business to continue to serve the customer. There >are good reasons why geophysical gear costs so much. > >I don't mean to jump on John E. or fault his science. It's just that >the cost projections glared out at me and I thought I would speak up for >the manufacturers. >-- >Doug Crice web site http://www.georadar.com >GeoRadar Inc. e-mail dcrice@............ >19623 Via Escuela Drive phone 408-867-3792 >Saratoga, CA 95070 USA fax 408-867-4900 > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: The Design and Performance of a Low-cost Strong-motion - Date: Wed, 14 Apr 1999 18:07:38 -0700 .... > I wish Winquake could read 24 bit ascii data.... The new beta release (the one with the new map / location feature) of WinQuake can read in an ASCII formatted event files. Unlike the PSN binary format, the ASCII format can handle numbers larger then +-32K (16 bits). WinQuake reads each data point in as a floating point number, but rounds the number to the nearest whole number. Too see what the format looks like, save an event file in the text (ASCII) format and read it in using an editor. Not all of the fields need to be in the file, only the main ones like start time, SPS and data count. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Jim Esler" Subject: Re: The Design and Performance of a Low-cost Strong-motion - WinQuake ASCII.. Date: Tue, 13 Apr 1999 21:08:42 -0500 Thanks, I don't have the latest version - but I will look into it soon. :) Jim -----Original Message----- From: Larry Cochrane To: PSN-L Mailing List Date: Wednesday, April 14, 1999 8:08 PM Subject: Re: The Design and Performance of a Low-cost Strong-motion - WinQuake ASCII.. >... >> I wish Winquake could read 24 bit ascii data.... > >The new beta release (the one with the new map / location feature) of >WinQuake can read in an ASCII formatted event files. Unlike the PSN binary >format, the ASCII format can handle numbers larger then +-32K (16 bits). >WinQuake reads each data point in as a floating point number, but rounds >the number to the nearest whole number. > >Too see what the format looks like, save an event file in the text (ASCII) >format and read it in using an editor. Not all of the fields need to be in >the file, only the main ones like start time, SPS and data count. > >-Larry Cochrane >Redwood City, PSN > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Re: VBB vertical Date: Thu, 15 Apr 1999 08:10:36 -0400 Karl, I think I understand your approach, though I want to try to express it slightly different terms to see if I'm getting it right.. I had it pounded into my head that feedback can not compensate, reduce, cancel.... noise that comes in with the signal--the system can't tell the difference. In the VBB case I'll define noise to include thermal drift, barometric effects, spring creep, and everything else. Specifically, the ratio of signal to noise in any frequency band can not be improved by adding feedback. However I think that's not what you were suggesting. If I understand, you were saying that you would be happy if you could reduce the sensitivity to *both* signal and noise at the very lowest frequencies. And in particular you want the response to acceleration (=force) to approach zero at the DC end of the spectrum. Suppose we have a loop whose accelleration response falls steadily (by a factor of 10 per decade) with decreasing frequency, say from 0,011 Hz sec all the way back to some really low frequency, like a cycle per several hours, or even lower. That may be a bit much to ask, but as long as the loop is still in control at the very low frequencies, the response to very slowly changing forces (spring creep, etc) will be reduced right along with the acceleration response. Then all you would have to do is to get those variations to be slow enough to not get into the working frequency band. Sounds so easy. Why do I think that may be the really tough problem? Integrating that into a velocity response, you're saying that you want the response curve to continue to fall by 100 for each decade (40 db/decade) as you go down toward DC. I need to look at this more, but as you indicated it appears that the key to doing that is to increase the integrator time constant perhaps by a factor of 100 or more. It may be that you'd need to make some changes in the proportional term, too, but that's not clear yet. That's a challenging design goal, but I'm pretty sure that the electronic devices and techniques exist to do it. Probably would involve an electrometer amplifier IC, a very good capacitor and the use of active guarding techniques and good shielding. And you'd probably need to invest in at least one high value resistor. But with effort, it ought to be possible. When you were through doing that, the high pass filter in the velocity output could probably go out as its effect would then be incorporated in the loop. Please let me know if I've missed the point here. I think we're tracking along very similar lines. Brett At 09:08 AM 4/14/99 -0700, you wrote: >Brett, Barry, and others -- > >An approach I forsee is much as Brett described -- have the integrator >portion of the feedback compensate for at least some of the creep. This >goes along with another similar problem (maybe larger), temperature >compensation. Even with bimetal springs for compensation, there will still >be some left over to deal with. > >I think it should be possible to insulate and temperature control the >enclosure so that creep and the rate of spring force change due to >temperature are substantially below the output bandwidth. If this is the >case, the integrated feedback path should take care of it, provided it has >enough force at its disposal to do the job. Increasing the amount of >integrator feedback and its time constant (or some other variation) may >accomplish that, or perhaps including another much slower integrator path >with more range. However, it probably comes at the expense of noise due to >coupling in more electronic noise as feedback force. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: robert barns <75612.2635@..............> Subject: Re: VBB vertical Date: Thu, 15 Apr 1999 10:42:59 -0400 Hi, Here's some ancillary info on the creep of steel. On p. 143 of "Piano Servicing, Tuning & Rebuliding" by Art Reblitz, 1976 (an excellant book which I helped to edit) it sez (in the section about installing new strings) "It usually takes ...two or three tunings before a piano will still be in tune by the time a tuning is completed. New strings will continue to stretch for several months of hard use or for up to several years [!!!] if not played very much." [my emphasis] As a guess, I thi= nk piano strings are tensioned up to about half the elastic limit. This is pretty high but not too far from the seismometer case. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rex Klopfenstein, Jr." Subject: VBB Resistor Calculations Date: Thu, 15 Apr 1999 12:34:21 -0400 Sean I have a general question about the Effective Period selector switch. How did you calculate the resistor values for the RI and Rp? Did you use your model? -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: SEISAN seismic data analysis software package Date: Thu, 15 Apr 1999 11:53:55 -0600 (MDT) Angel, As it turns out, I'm taking a close look at the seisan software too, and will try to get it running on my PC. Did you get it from the University of Bergen ftp site: ftp.ifjf.uib.no in pub/seismo? Version 7 is not fully tested yet, but should be ready in June. This is a very impressive collection of software that could be of great help to amateur and professional seismologists alike. Please give us some feedback as to how well it's working for you. You mentioned a psn to seisan conversion program. Did this program come with Version 6? I didn't see it with Version 7. Also, you mentioned a program to convert from psn to seisan format. I thought I saw mention of this within the seisan documents, but can't find it again. Did you write this program? In any case, could you put a copy onto your ftp site for me? Thanks, JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: VBB vertical Date: Thu, 15 Apr 1999 11:49:14 -0700 Brett -- I think you've got it, but there's a couple of points I'd like to clarify: >If >I understand, you were saying that you would be happy if you could reduce >the sensitivity to *both* signal and noise at the very lowest frequencies. >And in particular you want the response to acceleration (=force) to >approach zero at the DC end of the spectrum. If we are talking about response at the output to signals or noise at the input (including creep, etc.), the VBB system already has poor response at the lowest frequencies. The response curve demonstrates that. And because of the integrator term in the feedback function, the loop tries its hardest to compensate for very low frequency noise like spring creep. The is because the loop gain at extremely low frequencies is high. If the displacement detector (which is DC coupled) detects an offset from null, the feedback integrator's output will keep increasing (to the stops if it has to), in the process feeding more and more compensating force back to the spring via the voice coil. Assuming it doesn't hit the stops first and assuming it can keep up with the rate of change (more about this later), eventually the compensating force will balance the spring creep and it will reach a new equilibrium. The problem is that in the process, the output of the displacement detector has had a signal in it which will wind up at the output. The integrator output will have a dc offset proportional to the amount of the compensating force. This is the response to very low-frequency acceleration. The velocity output has to be ac coupled to block this offset, but I believe it's that way already. Here's another way to look at it (which I think is true): So long as the system has a reasonable amount of loop gain, the amount of current through the voice coil will always be proportional to the acceleration the coil is imparting to the system, which provides a restoring force to system imbalances. Since the voice coil's resistance is low, this current is close to proportional to the voltage across each of the three feedback resistors. At very low frequencies, the integrator path is dominant. Since the integrator output is acceleration (because it's fed to the voice coil), the input to the integrator is the derivative of acceleration (which is not very useful for the most part, but can be used to measure rate of change of low-frequency drifts like spring changes). At higher frequencies (within the bandpass of the velocity output), the derivative term is dominant. Since the derivative term's output is acceleration, its input is the integral of that, or velocity (which is what we want as the overall output). Somewhere in between is the proportional term, which I don't think is ever very dominant, but I'm not too sure about this. I believe the VBB feedback system already has the right topology including the feedback to compensate for spring creep, etc. To be determined are the needed coefficients in the feedback system to do the compensation. If the maximum rate of change of spring force due to temperature and creep can be estimated, try feeding that into the equations as if it were an input acceleration change per unit time. (This can likely be done by approximating it with a sine-wave with the same maximum slew rate.) At these very low frequencies, I think the voltage at the velocity output will be proportional to the rate of change of spring force, and it will appear at the velocity output as a dc offset for a constant rate of change. Of course, in practice the spring rate of change isn't constant so there will be something other than dc at the output. The next step is to determine how the VBB feedback terms can be changed to try to keep the effect of spring changes as seen at the output below a certain level. It may be necessary to use a higher-order integrator to get from here to there. Or perhaps increasing the time constant (or the order of the function) of heat flow in and out of the enclosure would be less trouble. Another benefit may be that effects of temperature drift and aging of the electronic components (including the integrators) can be cancelled as well. Enough rambling. Am I hitting on the points you want me to? If not, please ask again, Brett. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: Re: VBB Resistor Calculations Date: Thu, 15 Apr 1999 15:42:51 -0500 (CDT) Rex, Some brief answers: 1. The schematic of the quad-amplifier circuit card has not been updated since January to keep up with the newer overall schematic of the multi-period VBB of April 5. There are also minor errors on that schematic that instantly appeared as I returned from posting the stack of SASEs, like the oscillator is 600hz, not 5khz. 2.Specifically, the "gain set" resistor at the terminal strip does not exist; it was left over from something else. The terminal strip is just a convenience (a remnant of a lightning protection interface), and can be cut and pasted/soldered to provide sites for all the feedback components for a fixed period instrument. Look at the info on the April 5 schematic for its latest configuration. The resistor R3 at the lower A2 (which should be labeled A4) is an option for attenuating the input to A4 for less gain rather than changing R4, which would also require changing the parallel capacitor. Also, the lower A1 (should be A3) overall gain is x4. I will edit that schematic before I send it out again. B.Regarding the multi-period configuration for educational use: 1.The values of Rp and RI are calculated from the transfer function using the equations expressed there. To do this, I pre-set Cp to 20uf (as shown on the schematic); this fixes the output level at a constant value of 2000 v/m/sec for all periods, and the upper corner of the response at 80 hz, (with the other hardware values). Then I picked a convenient TI value (of 10, 20, or 40 seconds, to keep the number of integrator capacitors to a minimum), pre-set the damping at 0.7071, and calculated Rp and RI. I actually calculated about 30 options from 1 second to 960 seconds, choosing 1,20,40,80,160,and 320 seconds as the schematic shows. The 1 second period is for rapid settling down after adjustments, such as operationg the zeroing motor. The 20 second period is much less sensitive to barometric noise (vertical) or local tilts of a horizontal. 2. The 5-digit resistor values listed are from above; for each I picked the closest TWO 1% values that add up to the value. This need only be as accurate as the capacitors you use. I bought 40 10uf poly caps from Mouser and measured each to 0.01uf. The closest to 10.00 are used for the 10 and 20 uf values; the remaining high/lows are paralleled for the 30uf value. (they ranged from 9.6 to 10.5). 3. Yes, the switch is a four pole, 6-position sealed switch. For a simpler configuration, a 2-postion switch could be used, one for the 1-second period, and the other for the operating period. Or the one-second values could be switched in with a relay that is also operated by the zeroing motor switch. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: Re: VBB Resistor Calculations Date: Thu, 15 Apr 1999 15:42:51 -0500 (CDT) Rex, Some brief answers: 1. The schematic of the quad-amplifier circuit card has not been updated since January to keep up with the newer overall schematic of the multi-period VBB of April 5. There are also minor errors on that schematic that instantly appeared as I returned from posting the stack of SASEs, like the oscillator is 600hz, not 5khz. 2.Specifically, the "gain set" resistor at the terminal strip does not exist; it was left over from something else. The terminal strip is just a convenience (a remnant of a lightning protection interface), and can be cut and pasted/soldered to provide sites for all the feedback components for a fixed period instrument. Look at the info on the April 5 schematic for its latest configuration. The resistor R3 at the lower A2 (which should be labeled A4) is an option for attenuating the input to A4 for less gain rather than changing R4, which would also require changing the parallel capacitor. Also, the lower A1 (should be A3) overall gain is x4. I will edit that schematic before I send it out again. B.Regarding the multi-period configuration for educational use: 1.The values of Rp and RI are calculated from the transfer function using the equations expressed there. To do this, I pre-set Cp to 20uf (as shown on the schematic); this fixes the output level at a constant value of 2000 v/m/sec for all periods, and the upper corner of the response at 80 hz, (with the other hardware values). Then I picked a convenient TI value (of 10, 20, or 40 seconds, to keep the number of integrator capacitors to a minimum), pre-set the damping at 0.7071, and calculated Rp and RI. I actually calculated about 30 options from 1 second to 960 seconds, choosing 1,20,40,80,160,and 320 seconds as the schematic shows. The 1 second period is for rapid settling down after adjustments, such as operationg the zeroing motor. The 20 second period is much less sensitive to barometric noise (vertical) or local tilts of a horizontal. 2. The 5-digit resistor values listed are from above; for each I picked the closest TWO 1% values that add up to the value. This need only be as accurate as the capacitors you use. I bought 40 10uf poly caps from Mouser and measured each to 0.01uf. The closest to 10.00 are used for the 10 and 20 uf values; the remaining high/lows are paralleled for the 30uf value. (they ranged from 9.6 to 10.5). 3. Yes, the switch is a four pole, 6-position sealed switch. For a simpler configuration, a 2-postion switch could be used, one for the 1-second period, and the other for the operating period. Or the one-second values could be switched in with a relay that is also operated by the zeroing motor switch. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Angel Rodriguez Subject: Re[2]: SEISAN seismic data analysis software package Date: Thu, 15 Apr 1999 19:54:08 -0500 Hello John, Thursday, April 15, 1999, 12:53:55 PM, you wrote: JL> As it turns out, I'm taking a close look at the seisan software too, JL> and will try to get it running on my PC. Did you get it from the JL> University of Bergen ftp site: ftp.ifjf.uib.no in pub/seismo? I am running Seisan Ver. 6 and I made a copy of the CDROM they have at the Univeristy of Panama. On the CD and probably on the FTP in Norway there is a Zipped version for the PC which is about 18 megs big. I met Jens Havskov at the UPA and he encourged me to to try it. When I told him that I wanted to do more than just look at the traces. JL> This is a very impressive collection of software that could be of JL> great help to amateur and professional seismologists alike. JL> Please give us some feedback as to how well it's working for you. JL> You mentioned a psn to seisan conversion program. Did this JL> program come with Version 6? I didn't see it with Version 7. What I have like the most is that it manages my events in a database which the collect of programs then access. I have six channel cause eventually I want matched 3 componnent long period and 3 short period. With MULPLT one of the Seisan programs I can look at all six traces at once. I can pick phases and save to the database. I can compute azimuth from the the short period 3 component device and then plot epicenters with the mapping program. I'm just begining to learn about the other programs. I'm just exploring many of other programs. If those of us that have accurate time post our data, the locating program could use the different arrival times from the P an S and we could plot epicenter maps and who know what else with Hyopcenter, also included in seisan. I am using SEISAN almost exclusively for everything but the intitial look at the events, for which I use Winquake. I only wish that seisan was a easy to use and graphicly atractive as Winquake. Seisan is really a command prompt program UNIX style. I have quit using the GUI for W95/98 that comes with the package. JL> Also, you mentioned a program to convert from psn to seisan format. JL> I thought I saw mention of this within the seisan documents, but JL> can't find it again. Did you write this program? In any case, JL> could you put a copy onto your ftp site for me? I did not write the converison program, now in it´s third verion. Prof Jens Havskov the programer/editor of seisan wrote it. There is no mention of it in Version 6.0. I hope he adds it to Ver 7 I have posted it along with the seisan manual in PDF format and a file called epimap also in PDF which is a epicenter map for local event around my station. To convert from PSN to SEISAN run PSNSEI3.exe and it will prompt you for a file name. Give it the PSN filename and it will output a SEISAN file. I would be more than glad to help anyone in any way I can. I can post any or all of the component to my FTP but please know that my computer is at the end of a verly onlg line of satalite links and rounters. Best regards, Angel _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Al Allworth" Subject: Re: VBB vertical Date: Thu, 15 Apr 1999 23:53:59 -0700 Karl and Brett, Since the digital stream contains the offset due to these mechanical drifts could the stream be resampled appropriately using an algorithm to recognize an event and if none then average several samples to produce a filtered offset (digital) and once a day (or other appropriate interval) compare with the centered value and adjust a latched value into a D to A which could drive an auxilary coil providing the centering force needed to keep the existing electronics centered. Kind of a long sentence but it should give you some idea of what I have in mind. I have seen similar processes used in equipment I have worked on and made modifications to. I hope this might help solve the drift problem. ____________________________________ Al Allworth allworth@.............. Gold Beach On The Beautiful Southern Oregon Coast ____________________________________ ----- Original Message ----- From: Karl Cunningham To: PSN-L Mailing List Sent: Thursday, April 15, 1999 11:49 AM Subject: Re: VBB vertical > Brett -- > > I think you've got it, but there's a couple of points I'd like to clarify: > > >If > >I understand, you were saying that you would be happy if you could reduce > >the sensitivity to *both* signal and noise at the very lowest frequencies. > >And in particular you want the response to acceleration (=force) to > >approach zero at the DC end of the spectrum. > > If we are talking about response at the output to signals or noise at the > input (including creep, etc.), the VBB system already has poor response at > the lowest frequencies. The response curve demonstrates that. And because > of the integrator term in the feedback function, the loop tries its hardest > to compensate for very low frequency noise like spring creep. The is > because the loop gain at extremely low frequencies is high. If the > displacement detector (which is DC coupled) detects an offset from null, > the feedback integrator's output will keep increasing (to the stops if it > has to), in the process feeding more and more compensating force back to > the spring via the voice coil. Assuming it doesn't hit the stops first and > assuming it can keep up with the rate of change (more about this later), > eventually the compensating force will balance the spring creep and it will > reach a new equilibrium. The problem is that in the process, the output of > the displacement detector has had a signal in it which will wind up at the > output. > > The integrator output will have a dc offset proportional to the amount of > the compensating force. This is the response to very low-frequency > acceleration. The velocity output has to be ac coupled to block this > offset, but I believe it's that way already. > > Here's another way to look at it (which I think is true): So long as the > system has a reasonable amount of loop gain, the amount of current through > the voice coil will always be proportional to the acceleration the coil is > imparting to the system, which provides a restoring force to system > imbalances. Since the voice coil's resistance is low, this current is > close to proportional to the voltage across each of the three feedback > resistors. At very low frequencies, the integrator path is dominant. > Since the integrator output is acceleration (because it's fed to the voice > coil), the input to the integrator is the derivative of acceleration (which > is not very useful for the most part, but can be used to measure rate of > change of low-frequency drifts like spring changes). At higher frequencies > (within the bandpass of the velocity output), the derivative term is > dominant. Since the derivative term's output is acceleration, its input is > the integral of that, or velocity (which is what we want as the overall > output). Somewhere in between is the proportional term, which I don't > think is ever very dominant, but I'm not too sure about this. > > I believe the VBB feedback system already has the right topology including > the feedback to compensate for spring creep, etc. To be determined are the > needed coefficients in the feedback system to do the compensation. If the > maximum rate of change of spring force due to temperature and creep can be > estimated, try feeding that into the equations as if it were an input > acceleration change per unit time. (This can likely be done by > approximating it with a sine-wave with the same maximum slew rate.) At > these very low frequencies, I think the voltage at the velocity output will > be proportional to the rate of change of spring force, and it will appear > at the velocity output as a dc offset for a constant rate of change. > > Of course, in practice the spring rate of change isn't constant so there > will be something other than dc at the output. The next step is to > determine how the VBB feedback terms can be changed to try to keep the > effect of spring changes as seen at the output below a certain level. It > may be necessary to use a higher-order integrator to get from here to > there. Or perhaps increasing the time constant (or the order of the > function) of heat flow in and out of the enclosure would be less trouble. > > Another benefit may be that effects of temperature drift and aging of the > electronic components (including the integrators) can be cancelled as well. > > Enough rambling. Am I hitting on the points you want me to? If not, > please ask again, Brett. > > > Karl Cunningham > La Mesa, CA. > PSN station #40 > karlc@....... > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: WinQuake beta expiration... Date: Fri, 16 Apr 1999 01:15:34 -0700 WinQuake Users, For those of you who are using the current beta release of WinQuake, the one with the new map / location feature, you will (should) start seeing an expiration message. I was hoping to release an "official" release before the beta release times out. As usual, I'm stuck at the documenting phase..... I will release a new beta version in a day or two that moves the time out period out a few more months. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Re: VBB vertical Date: Fri, 16 Apr 1999 09:30:30 -0400 Al, Very interesting thought. I can't see any reason why it shouldn't work. I'm thinking that you might even want to try sampling a little more often, say several times per minute, so that with a D/A having enough bits, you could be putting in very small corrections all the time that wouldn't be noticed in the data. And you really ought to be able to sum your correction signal (current) right into the main coil without having to go to the trouble of adding another one. Random thought: If you used some sort of Sigma/Delta-like approach, sampling the data fairly often and decrementing a counter when ever the sample was positive and incrementing it when the sample was negative. If you had enough bits in the counter (20 or 30?), you could pick off your D/A signal from some of the higher order bits and still have enough resolution to not mess up the data. Anyone know how to go about analyzing the frequency characteristics of that sort of approach? Taking that a big step further, I've occasionally wondered about a feedback loop in which all the frequency sensitive feedback elements (essentially the P/D/I branches) got replaced by a digital filter, with an A/D at its input and a D/A at its output. And having gone that far, you might even be able to figure out how to derive your data output directly from the digital feedback stream. That would make one serious seismometer. Digital filtering seems to be so well adapted to this low frequency environment that some really neat things ought to be possible. You'd have to know a lot more about digital filters than I do to design that, but I wonder if it might not work out really well. >at 11:53 PM 4/15/99 -0700, you wrote: >Karl and Brett, > >Since the digital stream contains the offset due to these mechanical drifts >could the stream be resampled appropriately using an algorithm to recognize >an event and if none then average several samples to produce a filtered >offset (digital) and once a day (or other appropriate interval) compare with >the centered value and adjust a latched value into a D to A which could >drive an auxilary coil providing the centering force needed to keep the >existing electronics centered. > >Kind of a long sentence but it should give you some idea of what I have in >mind. I have seen similar processes used in equipment I have worked on and >made modifications to. I hope this might help solve the drift problem. >____________________________________ > >Al Allworth allworth@.............. > >Gold Beach > >On The Beautiful Southern Oregon Coast > >____________________________________ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "James M Hannon" Subject: Re: VBB vertical Date: Fri, 16 Apr 1999 09:15:52 -0500 From there description on the web page http://www.guralp.demon.co.uk/pepp/datasheet.htm it looks like the Gurlap PEPP seismograph works like you are thinking. One way of getting the DC component of the A/D output is to simply compute the long term running average of the sample values. Add up say ten minutes of samples and divide by the number of samples. If you subtract the resulting number from the incoming data you have removed the DC component of the data. You can also then use the number to supply feedback to the sensor. One thing that I worry about and haven't an answer for is that the coil with the DC feed back is going to act like a spring and may have an effective spring constant that would seriously reduce the mechanical time constant of the sensor. Jim Hannon Brett Nordgren on 04/16/99 08:30:30 AM Please respond to PSN-L Mailing List To: PSN-L Mailing List cc: Subject: Re: VBB vertical Al, Very interesting thought. I can't see any reason why it shouldn't work. I'm thinking that you might even want to try sampling a little more often, say several times per minute, so that with a D/A having enough bits, you could be putting in very small corrections all the time that wouldn't be noticed in the data. And you really ought to be able to sum your correction signal (current) right into the main coil without having to go to the trouble of adding another one. Random thought: If you used some sort of Sigma/Delta-like approach, sampling the data fairly often and decrementing a counter when ever the sample was positive and incrementing it when the sample was negative. If you had enough bits in the counter (20 or 30?), you could pick off your D/A signal from some of the higher order bits and still have enough resolution to not mess up the data. Anyone know how to go about analyzing the frequency characteristics of that sort of approach? Taking that a big step further, I've occasionally wondered about a feedback loop in which all the frequency sensitive feedback elements (essentially the P/D/I branches) got replaced by a digital filter, with an A/D at its input and a D/A at its output. And having gone that far, you might even be able to figure out how to derive your data output directly from the digital feedback stream. That would make one serious seismometer. Digital filtering seems to be so well adapted to this low frequency environment that some really neat things ought to be possible. You'd have to know a lot more about digital filters than I do to design that, but I wonder if it might not work out really well. >at 11:53 PM 4/15/99 -0700, you wrote: >Karl and Brett, > >Since the digital stream contains the offset due to these mechanical drifts >could the stream be resampled appropriately using an algorithm to recognize >an event and if none then average several samples to produce a filtered >offset (digital) and once a day (or other appropriate interval) compare with >the centered value and adjust a latched value into a D to A which could >drive an auxilary coil providing the centering force needed to keep the >existing electronics centered. > >Kind of a long sentence but it should give you some idea of what I have in >mind. I have seen similar processes used in equipment I have worked on and >made modifications to. I hope this might help solve the drift problem. >____________________________________ > >Al Allworth allworth@.............. > >Gold Beach > >On The Beautiful Southern Oregon Coast > >____________________________________ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: Rotating Horizontal Seismic Data Date: Fri, 16 Apr 1999 08:34:09 -0600 (MDT) Hi Angel, Thanks for the further information on seisan. I looked at your ftp site and didn't see PSNSEI3.EXE If you have it, I would like to get the FORTRAN source also. Maybe you could attach it to an Email to me at lahr@........ Thanks, JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Re: VBB vertical Date: Fri, 16 Apr 1999 11:40:26 -0400 Jim That's a mighty nice looking system. Think you're right about how the feedback works They show a picture of a circuit board (1 of 2, I think) and considering that includes everything but the computer, it appears to be a very cost-effective design. Anyone know what this PEPP system costs? Probably still too much, but since it's aimed at schools, should be a bit cheaper than some. Brett At 09:15 AM 4/16/99 -0500, you wrote: > > >From there description on the web page >http://www.guralp.demon.co.uk/pepp/datasheet.htm it looks like the Gurlap >PEPP seismograph works like you are thinking. > > >One thing that I worry about and haven't an answer for is that the coil >with the DC feed back is going to act like a spring and may have an >effective spring constant that would seriously reduce the mechanical time >constant of the sensor. > >Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Phil Giannini Subject: GPS Receivers Date: Fri, 16 Apr 1999 11:33:11 -0700 Hi Gang, With lots of talk about GPS receivers lately I thought I'd throw my two cents in with this little piece of FYI.... A while ago I purchased a surplus GPS receiver from an outfit called Communications Surplus, (713)526-8000 or 1(877)878-6GPS lshaefer@.......... They run an add in Nuts And Volts magazine every month. (March issue pg.57 lower right for example.) The unit I purchased was made by Trimble and was called the Placer 400. It is a 6 channel device about 5 inches square and about an inch thick. The receiver comes with a 3" diameter antenna and it operates off of 12 vdc. These devices were originally used in a tracking system for delivery vans, emergency vehicles and the like. The cost is $59.00 and the receiver comes with paper work and a software package to program it and to create a rather crude maping grid to show movement and location. The software package can be downloaded from Trimble's FTP site to save a couple of bucks. There is also some info available on the unit on Trimble's website at: http://www.trimble.com/products/catalog/public/place400.htm Although the receiver I purchased was slated for a use other than locking my recoder, it does have a one pulse per second output that comes from pin 9 of a DB9 (RS232) connector located on the receiver's chassis. Regards, Phil SFN & SFZ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Kevin J. Rowett" Subject: Re: GPS Receivers Date: Fri, 16 Apr 1999 11:55:44 -0700 Some versions of that unit have GPS week rollover problems. Check Trimble's home page.... KR At 11:33 AM 4/16/99 , you wrote: >Hi Gang, > > The unit I purchased was made by Trimble and was called the Placer >400. It is a 6 channel device about 5 inches square and about an inch >thick. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Re: VBB vertical Date: Fri, 16 Apr 1999 12:50:57 -0700 Brett Nordgren wrote: > Anyone know what this PEPP system costs? Probably still too much, but > since it's aimed at schools, should be a bit cheaper than some. I think I saw <$1500 somewhere. ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: VBB vertical Date: Fri, 16 Apr 1999 15:46:52 -0700 About digital filtering, etc... The magazine "Embedded Systems Programming" has had several articles on the subject. Search for filter at http://www.embedded.com/escfrm.htm . I agree with Brett that digital is the way to go. Theoretically, one should be able to digitize the displacement transducer's output and generate both the feedback and the output signals simultaneously. I think this is probably within our reach. Software is quite a bit better than hardware at implementing very-low-frequency filtering, integration, and differentiation. Or take it a step further and don't even bother with the feedback. I'm sure it's not practical, but one should be able to measure and then digitally subtract off the peculiarities of the undamped mechanical system (including parasitic resonances) and have only a suspended mass, a displacement transducer, digitizer, and software to generate any desired output. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Re: VBB vertical Date: Fri, 16 Apr 1999 16:09:45 -0700 One thing I like about digital filtering is that you can filter without changing the phase of the signal. This is possible because digital filters can look into the future as well as the past, wheras analog filters only look into the past. Of course they really don't look into the future, but if you store a sequence of samples in memory, you can re-define the present and the incoming stuff becomes the future. -- Doug Crice web site http://www.georadar.com GeoRadar Inc. e-mail dcrice@............ 19623 Via Escuela Drive phone 408-867-3792 Saratoga, CA 95070 USA fax 408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Re: VBB vertical Date: Fri, 16 Apr 1999 20:09:47 -0400 Doug & Karl, Only one thing was bothering me. Seems like digital filters often have built in time delays. Feedback loops *really* don't like time delays. It's making me wonder if they're going to be all that easy to apply. It's pretty sure that you do want to actually close the loop around to the mass, if only to improve the system linearity. Brett _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Re: VBB vertical Date: Fri, 16 Apr 1999 17:24:29 -0700 You can make digital filters with and without time delays. The ones with zero phase shift do have time delays. The ones that emulate analog filters have the same phse shift as analog filters. However, the math is pretty complex, not too complex for many PSN members, but too complex for me. If designing feedback systems, I would use analog methods to eliminate the analog to digital back to analog process. On the other hand, my wife has a thing called a "key changer" she got at the Karaoke store. You play a music tape into it and it comes out the other end in a different key (but at the same speed) adjusted up and down in quarter key steps to match your vocal range. A remarkable piece of real time digital signal processing for $200 retail. -- Doug Crice web site http://www.georadar.com GeoRadar Inc. e-mail dcrice@............ 19623 Via Escuela Drive phone 408-867-3792 Saratoga, CA 95070 USA fax 408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Wayne Abraham J73WA Subject: DPSN Station Upgrade Date: Fri, 16 Apr 1999 21:49:04 -0400 PSN Just a note to inform you that thanks to Larry Cochrane and Ed Cranswick, the Dominica Public Seismic Network seismic station now has proper timing. I installed the new Motorola Oncore UT+ GPS receiver today and it's working very well. We have already been rewarded with a beautiful Ml2.9 earthquake which I have posted on Larry's archive for viewing for everyone. Wayne. -- Wayne Abraham 1430 Rodney Street Portsmouth, Dominica abrahamw@........ http://www.freeyellow.com/members6/dominicapsn/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: meredith lamb Subject: Re: DPSN Station Upgrade Date: Fri, 16 Apr 1999 22:05:42 -0600 Hey Wayne....you sure made alot of changes and improvements on your site since I last hit it up maybe acouple weeks back. Its looking great! Meredith Lamb Wayne Abraham J73WA wrote: > PSN > > Just a note to inform you that thanks to Larry Cochrane and Ed > Cranswick, the Dominica Public Seismic Network seismic station now has > proper timing. I installed the new Motorola Oncore UT+ GPS receiver > today and it's working very well. We have already been rewarded with a > beautiful Ml2.9 earthquake which I have posted on Larry's archive for > viewing for everyone. > > Wayne. > > -- > Wayne Abraham > 1430 Rodney Street > Portsmouth, Dominica > > abrahamw@........ > http://www.freeyellow.com/members6/dominicapsn/ > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Stephen Caruso" Subject: Re: VBB Resistor Calculations Date: Sat, 17 Apr 1999 02:39:36 -0400 Do you have any info on Tornados and seismic interpretation? I know there was aconference sometime ago. We have a new 14 unit sesmic network in Ohio and the Lead oerson is looking for help! Stephen Caruso _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Dennis W. Pope" Subject: Installation Location Date: Sat, 17 Apr 1999 08:21:08 -0400 I am about to install my first seismometer - a vertical. I have two choices. We have a half basement half crawl space. The crawl space is easily accessable and very dry. I am thinking the crawl space may be the best location. It should provide more de-coupling from the building structure than the concrete basement floor. I would set a concrete pad on= the dirt in the crawl space. Does anyone have any ideas regarding this idea? We are sitting on glacial moraine here in central Ohio. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: DSP e-book Date: Sat, 17 Apr 1999 08:28:08 -0400 To all, who, like me, would like to understand more about Digital Signal Processing. This is an e-book, full text, of a $60 book on DSP, written for people who know nothing about DSP. Assumes very little previous knowledge, with lots of explanation of terms, and real-world applications. http://www.dspguide.com/ I'd be interested in what you folks who really understand this stuff think about it. To a beginner, this seems like exactly what I've been looking for. Brett _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: tornado seismic noise Date: Sat, 17 Apr 1999 12:15:58 -0500 (CDT) Stephen, Tornadoes are an atmospheric phenonemon and impart very little energy into the ground that a seismic instrument might record at at a sufficient distance such that several seismometers would sense the event so that it could be located or tracked. The most common description of tornado noise is that it is similar to a passing freight train. Where it passes it certainly will make noise that a seismometer will record, just as any strong wind will. We had a tornado here last spring that passed about 0.5 km north of the farm here and later trashed an industrial area about 1 mile east. I did see the noise from the VBB sensor in the basement, as well as in the telemetered data from the station in the back field. But no other stations recorded it. And if I had not known about the tornado, (I was sitting here watching it), I would not have suspected that the noise was anything other than a localized strong wind. In operating the 56=station array in the bootheel of MO for 20+ years, we never saw anything from the frequent tornadoes in the area. Wind noise does not propagate very far, a useful feature for us in the Aleutian network where we could decide to go to a station on one end of an island even though we could see gale-force wind noise in the data from the station at the other end about 10km away. We could actually track the fronts moving in off the Bearing sea. But these were not the very localized noise that a tornado creates. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: meredith lamb Subject: Re: Installation Location Date: Sat, 17 Apr 1999 11:45:54 -0600 "Dennis W. Pope" wrote: > I am about to install my first seismometer - a vertical. I have two > choices. We have a half basement half crawl space. The crawl space is > easily accessable and very dry. I am thinking the crawl space may be the > best location. It should provide more de-coupling from the building > structure than the concrete basement floor. I would set a concrete pad on > the dirt in the crawl space. Does anyone have any ideas regarding this > idea? We are sitting on glacial moraine here in central Ohio. > > Dennis Pope, Good deal on getting close to have a seismometer running. I also have a dirt crawlspace I'am using under my house. I located it in the quietest corner of the house from upstairs traffic, in my case, under the bedroom. The ground dampness here varys from the time of year, from very dry in the summer to a obvious moisture content (no dust particles in the air). Suggest some digging down to more compacted soil, and laying in a relatively large pier (which can be very awkward to do with any limited head/crawl space). It takes time to do this, but I think it pays off in much more stability from seismo drift over time. I probably went to more extreme for my location with the varying moisture content problem, and dug down enough to have space for the seismo covers removal, and, laid down a big plastic sheet; and then, built the piers on top of that. I also built a enclosure around the area using alot of insulation outside, inside and in the wall of the enclosure. Even the ceiling of the "vault" has alot of insulation. In effect its kind of like a insulated bubble to limit air and temperature changes influencing the seismos. I did use a corner area and built the vault walls attached to the structure, and their is some influence with that. However, outside the vault I have 2 more seismos, which have alot less temperature "accessories" around them, but I still see tilt effects from walking directly above in the house. I used to use just concrete pavers and a crude enclosure previously, but the new enclosure is many times better for stability. With the old I used to adjust for tilt about every 2 weeks, now, its about every 3 months with the new....so it paid to do it all, even though it was physically hard to construct. Probably it would pay off to plan for any contingencies and make extra space for everything and additions that possibly could occur in the future. Question.....are you going to use a vertical like the STM-8?, or is it something else? Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: sean@........... Subject: sensing quakes; accelerometers/seismometers Date: Sat, 17 Apr 1999 15:00:40 -0500 Jim, Some discussion concerning your several questions: a: Sensing earthquakes: They can be heard if you are close enough to the source region. Energy from breaking rock starts out as an acoustic effect at small fault dimensions or fragments of a larger rupture. But as the elastic waves propagate, the effect of dispersion rapidly lengthens the wavelength which lowers the frequency, such that within a few tens of km frequencies from 20hz to 1 hz dominate, and at telesiesmic or global distances the waves have periods of 1 to 100 seconds and up. Generally, it takes a Mb 2.7 at less than 5 km (distance and/ or depth) to be felt, but this depends on many factors. Also another consideration in reports of "hearing" a quake is whether it is the quake energy itself, or noise from the response of local structures to the ground motion. A place that I have often been able to hear earthquakes is in deep mines. The source (fault) lengths are of meters or less, but at 1km to 2km depths (such as the deep silver mines of Idaho), there is enough stress (caused by the mining excavations) to have "real" earthquakes. In the deep gold mines of Africa, these are a real problem if they occur near an opening or tunnel, where they are called rockbursts. We even have these in a 0.5km deep iron mine SW of here in the ozarks. Those studying mining quakes often record data frequencies up to 1 khz or higher, often using a 3-dimensional network of sensors, which allows them to locate the events within a few meters inside the mine. Then if the ground is "moving" in a particular part of the mine, operations can be avoided there for a while to prevent injuries from rockbursts. But the reports of people "seeing" surface waves are another matter. The actual amplitude for even moderate quakes is millimeters or less. One is hard pressed to imagine a visible wave moving down a street (or even a hallway in a building) without fracturing everything along its path. An explanation lies in the fact that the accelerations can be significant within more than a km or so of even a moderate quake. Even 0.1g will cause the fluid in the semi-circular ear canals of people to move. The usual explanation of "seeing surface waves" is that the person is incompletely aware of the accelerations and is unknowingly off balance, but the ear-canal feedback causes the person to un-consciously adjust their head or roll their eyes to accommodate it, resulting in the illusion of seeing the waves. It is sort of the reverse of sea-sickness, where the rolling of the boat moves the fluid, but the sense of motion is not supported by the visual cues of a person within the boat, where there is little or else contradictory relative motion. Hence the idea of "sea-legs", a relaxed stance we quickly learned that lets the feet and lower legs follow the deck motion while the upper body remains balanced and the visual reference is the horizon outside the boat. This could later have a reverse effect when back on land after a long day in a rolling boat: if one closed ones' eyes, a rolling sensation would quickly result and we would fall out of a chair or the shower. B: Accelerometers/seismometers: Because of the dispersion described above, arrays of seismometers are used where one wants many records of a given event. At a typical network station spacing of 10 to 40 km, most of the energy from even small quakes will be in the 20hz to 1hz range except at the very closest stations. For very close data, or "strong motion" data, where the structural response of a building or dam is desired, accelerometers are used. Since only forces related to engineering are desired, these are generally not sensitive to small local events that would cause useless triggering. Because of the intensity in the near field, accelerometers are used because a velocity sensor will quickly saturate or overload. Because of the high frequencies involved, accelerometer recording is usually triggered by the event, and only lasts tens of seconds. With the old SMA-1 photographic recorders, this meant that the first motion was only partially recorded (the time it took for the lamp to light and the motor to get the film moving). This is solved by digital recording with continuous pre-event memory. But a constant problem with triggered SMA (strong motion accelerographs) is maintenance. Most will wait months to years for an event. In the meantime the trickle-charged battery dries up, or the plug gets pulled because the new maintenance person doesn't know what the black box in the corner of the furnace room is all about. We had trouble with one at Adak when the Navy re-defined the boundaries of a top clearance area, including the SMA. With digital systems, the accelerometers can now be event-detected and recorded at a high sample rate in parallel with a broadband seismometer system, which provides the detection. Many of the IRIS global stations have a set of Streckheisns and a 3-component, 1-g accelerometer to record the local event that might break the hinges of the seismometers. But most broadband systems have a high dynamic range digitizer, often 24 bits, or 1 part in 16 million, so the velocity data is unlikely to saturate or overload. With a VBB with a flat velocity response with roll offs or corners well outside the frequencies/periods of interest, differentiating a velocity record to acceleration or integrating it to displacement is relatively easy. Regards, Sean-Thomas. Sean-Thomas Morrissey Saint Louis University Department of Earth and Atmospheric Sciences 3507 Laclede Ave. St. Louis, MO 63103 USA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Stacked chips Date: Sat, 17 Apr 1999 13:13:40 -0700 Just a thought: I've never seen anything more than 24 bit ADC chips. Please ignore the fact that I don't do a lot of looking for them. Wouldn't it be possible to use two 16 bit ADC as one 32 bit ADC? or four 16 bits as a 64 bit? or eight 16 bits as a 128 bit? Lets see the chips are what $20x8=160 and a custom made 128 bit chip costs $100,000 (a guess)? How's a 2^128=3.4e38 range sound for a $60 geophone? Big waste I know. Wouldn't it be neat if amateurs had something that the pros wanted for once? ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Conti Claudio" Subject: R: Stacked chips Date: Sat, 17 Apr 1999 22:37:34 +0200 fpjfvbolfombolfmbofmlobolboolmo olmbolfbolmomfolbolfbf obofombomfomofmbomol lfbfaafbaalfblklbkfkllflkflblak bafbafakafkbafakakbalkfbakfa lfbalfbalfabafaafakfabakbakak klalbkafbaabagfbalfbpfpe -----Messaggio originale----- Da: Greg A: psn-l@.............. Data: sabato 17 aprile 1999 22.14 Oggetto: Stacked chips >Just a thought: >I've never seen anything more than 24 bit ADC chips. Please ignore the >fact that I don't do a lot of looking for them. Wouldn't it be possible >to use two 16 bit ADC as one 32 bit ADC? or four 16 bits as a 64 bit? or >eight 16 bits as a 128 bit? Lets see the chips are what $20x8=160 and a >custom made 128 bit chip costs $100,000 (a guess)? How's a 2^128=3.4e38 >range sound for a $60 geophone? Big waste I know. > >Wouldn't it be neat if amateurs had something that the pros wanted for >once? > >,Greg > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Re: Stacked chips Date: Sat, 17 Apr 1999 13:52:03 -0700 Sorry Greg, The basic problem is that the most significant bit has to be as precise as the least significant bit. In other words, 1000000 should be just one bit more than 01111111. It's relatively easy to put any number of bits into an A/D converter, but to get the resistors matched to one LSB gets increasingly difficult as the number of bits increases. So, stacking two 16 bit A/D gives you so many errors that the results are equivalent to having just 16 bits. That's about as good as discrete A/D's get. The 24-bit A/D converters, and variations, use a method called "Delta Sigma" which is a whole nother process. The A/D keeps a running sum of the input signal and kicks it up or down a little depending on whether the new number is more or less than the old value. The input is a comparator. This is done quite fast, and the output of the comparator is sent through a DSP chip which figures out what the equivalent digital number would be. That number is further decimated and filtered to increase the number of bits. Delta Sigma converters are not particularly accurate as A/D's go, they don't make very good digital voltmeters, but they have outstanding resolution and monotonicity, which makes them good for seismographs. Because of the digital signal processing, it is uncommon to multiplex the inputs, and it takes a while for the right answer to come out. So they are assigned to one seismic channel and left turned on. A big advantage is that the process spits out a built-in anti-alias filter as a by product. It would be close to impossible to design such a filter with real parts. I suspect that 24 bits is close to the limit because of noise in the comparator and input amplifiers. As a general rule, putting an amplifier in front of a 24-bit A/D degrades the performance, so very careful design is required. -- Doug Crice web site http://www.georadar.com GeoRadar Inc. e-mail dcrice@............ 19623 Via Escuela Drive phone 408-867-3792 Saratoga, CA 95070 USA fax 408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: GPS position question Date: Sat, 17 Apr 1999 14:36:52 -0700 PSNer's Does anyone know what type of position accuracy one can expect from a GPS receiver with long term data averaging? Besides time information, SDR also gets position info. I added some code to SDR to take the position info, sampled every 15 minutes when SDR asks for time info, and creates a running average of the latitude, longitude and height of the GPS receiver. The user can then save this info in a file by pressing the "g" key. The specs for the ONCORE receiver is 100 m with SA (SA is information added by the DOD to the GPS signal to cause an error in the position calculation) and 25 m with it off. There is nothing about the accuracy with averaging of the data. I also ran into a strange problem that someone may know about. I had the GPS receiver here that Wayne in Dominica now has online. The receiver has a battery and even after two days of running in Dominica it still had my location in its memory and it looked like it was having problems tracking satellites. After temporarily removing the battery to clear out its RAM, it started working correctly. Very strange....It looks like I need to add a command to SDR (or create a simple command line program too do this) that will clear out the memory. There is one command that find that may work. It sets the receiver back to the default setting. This command clears out most of the info in RAM, but not all of it... Thanks for any information. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: Stacked chips Date: Sat, 17 Apr 1999 16:07:49 -0700 Greg What I have done, and maybe others also, is to record a few channels at varing gain ranges. With the speed of computers one can sample several channels.When an event occurs, review the gain that is not clipped. I was thinking of >16 bits but stopped due to multiple word locations in memory complicated my assemble program storage. Barry Greg wrote: > Just a thought: > I've never seen anything more than 24 bit ADC chips. Please ignore the > fact that I don't do a lot of looking for them. Wouldn't it be possible > to use two 16 bit ADC as one 32 bit ADC? or four 16 bits as a 64 bit? or > eight 16 bits as a 128 bit? Lets see the chips are what $20x8=160 and a > custom made 128 bit chip costs $100,000 (a guess)? How's a 2^128=3.4e38 > range sound for a $60 geophone? Big waste I know. > > Wouldn't it be neat if amateurs had something that the pros wanted for > once? > > ,Greg > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Stephen Caruso" Subject: Re: tornado seismic noise Date: Sat, 17 Apr 1999 19:39:40 -0400 We have this new seismic net of 14 sensors throughout the state and a #4 tornado recently so I thought something might be apparent but from your first hand account and knowing your expertise it does not seem to be a storm to chase! Hope you don't mind me forwarding this to Mike Hanson. He is the with the Ohio Geologic survey and in charge of the new 14 seismographs in Ohio. I was bugging him to see if anything did show up. Thanks Stephen Caruso -----Original Message----- From: S-T Morrissey To: psn-l@............. Date: Saturday, April 17, 1999 1:18 PM Subject: tornado seismic noise >Stephen, > >Tornadoes are an atmospheric phenonemon and impart very little >energy into the ground that a seismic instrument might record at >at a sufficient distance such that several seismometers would sense >the event so that it could be located or tracked. > >The most common description of tornado noise is that it is similar >to a passing freight train. Where it passes it certainly will make >noise that a seismometer will record, just as any strong wind will. >We had a tornado here last spring that passed about 0.5 km north of >the farm here and later trashed an industrial area about 1 mile east. >I did see the noise from the VBB sensor in the basement, as well as >in the telemetered data from the station in the back field. But no >other stations recorded it. And if I had not known about the tornado, >(I was sitting here watching it), I would not have suspected that >the noise was anything other than a localized strong wind. > >In operating the 56=station array in the bootheel of MO for 20+ years, >we never saw anything from the frequent tornadoes in the area. >Wind noise does not propagate very far, a useful feature for us in >the Aleutian network where we could decide to go to a station on >one end of an island even though we could see gale-force wind noise >in the data from the station at the other end about 10km away. We >could actually track the fronts moving in off the Bearing sea. But >these were not the very localized noise that a tornado creates. > >Regards, >Sean-Thomas > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Walt Williams" Subject: PSN-L: GPS Clock Date: Sat, 17 Apr 1999 18:20:46 -0800 Hello All, You aware of these guys? HTTP://www.tapr.org/tapr/html/tac2.html FYI. (if not) Walt Williams, 99.04.17 OSR _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: bits resolution Date: Sat, 17 Apr 1999 22:28:08 -0500 (CDT) Regarding the bits of resolution question. Sometimes the bits ante game reminds me of the competition between boaters/sailors over the length of their boats. Everyone wants 24 bits, or a resolution of 16 777 216 . But the dynamic range of most data is usually not worthy of the worry. If my maximum voltage is 10 volts, and the noise level is 200 microvolts, I have a range of 50 000. 16-bits is 1/65536 or half that if a sign bit is used. For a typical VBB signal of 4 000 volts/meter/second (after a 2x gain line amplifier), 200 microvolts is a velocity of 50 nanometers/second (assuming that the electronic noise is much less). Right now the 6-second microseisms are running about 4 millivolts here, being digitized by the 12-bit RS multimeter/digitizer. 4 mv is a velocity of 1 micron/second or a peak displacement of 1 micron at 6 seconds (omega = 2*pi/6). The least count is 0.1 mv, or 25 nanometers/second. Full scale is 200 mv, or 50 microns/second. So far, the 12-bit digitizer has clipped only twice, on a Mb7+ in Tibet and the recent 7+ event S of Kamchatka. So a 16-bit resolution would probably cover most teleseismic events at these sensitivities. A moderate regional event (6+ in CA) would probably clip the 16-bit signal, so I would use a low-gain channel, reduced by 40db (1/100), also with 16-bit resolution (as is frequently done, and as Barry notes). 16-bits with sign is 90db; a low gain (40db down) makes the total dynamic range 130db, or 1 part in 3 162 277 (with sign), or about the same as 22 bits. This can easily be done with Larrys 16-bit digitizer. The data from the low gain channels can be discarded almost continuously unless the high gain channel exceeds 80% of its range (for example), which could be managed with programming. 24-bits is nice to have, but a price is paid, both to get it, and to manage the large files that result. THe nicest 24-bit system I have seen is from Symres (using the Harris 7190 EDME for each channel); 8 channels for $1000, or with ViSeis for $1500. But I am not sure that it can sample more than 10hz, which seriously limits its application to higher frequency local data. As Doug described, the actual precision of these "Enhanced delta-modulation encoders" (EDME) is far from the actual resolution. In the Quanterra system, the actual digitizer is a high speed 16 bit system, but the DSP extends its dynamic range to 24 bits. The "Quantagrator" requires so much computer horsepower for the DSP (with multiple channels of FIR filters) that a separate 68000 CPU is used for each channel. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Phil Schmidt Subject: Re: Stacked chips Date: Sun, 18 Apr 1999 13:30:33 +0900 At 01:13 PM 4/17/99 -0700, you wrote: G'day Greg Being a student I often don't have the money to buy 16 bit adc's. What I would suggest you try is building an ADC out of a very accurate voltage comparator and a 16, 24 or 32 bit DAC or R2R network. Since most adcs are really just a DAC and a voltage comparator that either count up until the output voltage is equal to the input or they perform successive approximation. The later is a little hard to explain but it is the fastest method. Try researching the successive approximation from my point of view it the only way I can see to getting around the expensive chip problem. Cheers Philip Schmidt (South Australia) >Just a thought: >I've never seen anything more than 24 bit ADC chips. Please ignore the >fact that I don't do a lot of looking for them. Wouldn't it be possible >to use two 16 bit ADC as one 32 bit ADC? or four 16 bits as a 64 bit? or >eight 16 bits as a 128 bit? Lets see the chips are what $20x8=160 and a >custom made 128 bit chip costs $100,000 (a guess)? How's a 2^128=3.4e38 >range sound for a $60 geophone? Big waste I know. > >Wouldn't it be neat if amateurs had something that the pros wanted for >once? > >,Greg > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: PSN-L: GPS Clock Date: Sun, 18 Apr 1999 02:06:58 -0700 At 06:20 PM 4/17/99 -0800, Walt Williams wrote: >Hello All, > >You aware of these guys? > >HTTP://www.tapr.org/tapr/html/tac2.html > >FYI. (if not) They have a nice small interface board (see http://www.tapr.org/tapr/html/Ftac2.html) for the ONCORE receiver, almost exactly like I was going too make. I was going to place a 9 pin RS-232 connector on the board and also a connector for the 1 PPS TTL output. As far as I can tell their board does not have a buffered TTL 1PPS output. It does have a 1PPS output, but it has RS-232 (~+-12-15 volt) levels. This can't be feed directly into the TTL input on my board without converting to TTL levels. I could modify SDR so that it monitors the RS-232 comm port for the 1PPS signal. Their board costs $40.00 each. Since I really don't want to support another board, I will buy some from them... On their receiver; For some reason they offer the VP version of the ONCORE receiver. This is the most expensive version, at $179.00 each. I'm not exactly sure what the VP version has over the GT model that costs $108.00. Their version has the battery backup, this is a $10.00-$15.00 option. Both the VP and GT have the same timing accuracy of 500ns. I don't think either has better position information, so it may have something to do with DGPS. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Dennis W. Pope" Subject: PSN-L Digest for 17 Apr 1999 Date: Sun, 18 Apr 1999 07:21:49 -0400 Message text written by PSN-L Mailing List >Question.....are you going to use a vertical like the STM-8?, or is it something else? Meredith Lamb< Meredith - thanks for the information - just what I needed. I am installing a Guralp CMG-PEPPV. I realize this is near to heresy (not building the instrument yourself), but I wanted to quickly get one running, then start construction on one of another orientation. Thanks again, Dennis Pope. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: meredith lamb Subject: Re: PSN-L Digest for 17 Apr 1999 Date: Sun, 18 Apr 1999 10:03:50 -0600 "Dennis W. Pope" wrote: > Message text written by PSN-L Mailing List > >Question.....are you going to use a vertical like the STM-8?, or > is it something else? > > Meredith Lamb< > > Meredith - thanks for the information - just what I needed. > > I am installing a Guralp CMG-PEPPV. I realize this is near to heresy > (not building the instrument yourself), but I wanted to quickly get one > running, then > start construction on one of another orientation. Thanks again, Dennis > Pope. > Dennis Pope, Another more extensive helpful source is the Archive of PSN-L email messages: http://www.seismicnet.com/mailist.html#archives In particular, the 1st quarter 1998 text file if you can download and read that, there is alot of questions and answers and suggestions that I brought up at the time I was building my own crawlspace "vault". Of course to download them all, and read them all, can take days to do, but it might be worth it in the planning stages now, and save time overall, and yield success sooner. Good deal on the commercial unit you will use. Outside of geophones getting hold of commercial units (I tend to bargain hunt), is often a frustrating course in the battle of the budget, and being lucky enought to even find something useful.....anywhere. Three of my five seismometers are old commercial units, that I dragged around for many years before I had a place to put them in a relatively permanent "home". Have fun on the endeavor; its always fun to have goals one can achieve. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: GPS Date: Sun, 18 Apr 1999 18:50:13 +0200 Hi Larry. Some problems about the GPS. =20 Here in Italy, we have contacted the national retailer of the Motorola = Oncore products . =20 Unfortunately that is the situation: to get the receiver we must buy a = minimum of 20 pieces, that would cost about 100$ each. We cannot buy 1 = piece. Then, there is the problem of the interface. The Motorola = furnishes the driver and the software for connect the unit at Pc serial = port, but it costs straight 200 $! To get all these products we would = have to wait around 2 months! =20 I believe that you can offer (as you have told in a mail of yours, some = days ago), as optional to SDR, the whole proper instrumentation for the = GPS to the members of the PSN, or to whom as us, we don't live in USA = and couldn't find it. =20 If it's possible, let us know if the thing can be made and it general = cost. Ragards Francesco Nucera
Hi Larry.
Some problems about the GPS.  =
Here in=20 Italy, we have contacted the national retailer of the Motorola Oncore = products=20 .. 
Unfortunately that is the situation: to get the receiver we = must buy=20 a minimum of 20 pieces, that  would cost about 100$ each. We cannot = buy 1=20 piece. Then, there is  the problem of the interface. The Motorola = furnishes=20 the driver and the software for connect the unit at  Pc serial = port, but it=20 costs straight 200 $!  To get all these products we would have to = wait=20 around 2 months! 
I believe that you can offer (as you have = told in a=20 mail of yours, some days ago), as optional to SDR, the whole proper=20 instrumentation for the GPS  to the members of the PSN, or to whom = as us,=20 we don't live in USA and couldn't find it. 
If it's possible, = let us=20 know if the thing can be made and it general cost.
 
Ragards
Francesco = Nucera
From: "Kevin J. Rowett" Subject: Re: GPS position question Date: Sun, 18 Apr 1999 10:30:59 -0700 At 02:36 PM 4/17/99 , you wrote: >PSNer's > >Does anyone know what type of position accuracy one can expect from a GPS >receiver with long term data averaging? Besides time information, SDR also Tom Clark, from Nasa-Goddard did some initial work on this. After 24 hours averaging, 1 sample per second, your location is known within a about 6 minutes of a degree. >gets position info. I added some code to SDR to take the position info, >sampled every 15 minutes when SDR asks for time info, and creates a running >average of the latitude, longitude and height of the GPS receiver. The user >can then save this info in a file by pressing the "g" key. Tom created a program, Totally Accurate Clock (or TAC), that TAPR now re-sells. TAC will compute a mean on each new sample, and show the error of the sample from the mean calculated so far. After 24 hours, it doesn't get any better. TAC gets its 1PPS input from the serial port DCD pin. 15 minutes samples may not work too well. >The specs for the ONCORE receiver is 100 m with SA (SA is information added >by the DOD to the GPS signal to cause an error in the position calculation) >and 25 m with it off. There is nothing about the accuracy with averaging of >the data. The Oncore UT+ (The $170 unit) has built in position averaging. I don't think the GT+ has the feature in it, since the GT+ is targeted at the AVL market. For the UT+, with position hold set, the 1PPS sets down pretty close to 100 ns accuracy, if you ratchet in all the various cable and propagation delays. >I also ran into a strange problem that someone may know about. I had the >GPS receiver here that Wayne in Dominica now has online. The receiver has a >battery and even after two days of running in Dominica it still had my >location in its memory and it looked like it was having problems tracking >satellites. After temporarily removing the battery to clear out its RAM, it >started working correctly. Very strange....It looks like I need to add a I've observed this on occasion with the UT+. KR _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Re: Stacked chips Date: Sun, 18 Apr 1999 10:45:09 -0700 Doug Crice wrote: > The basic problem is that the most significant bit has to be as precise > as the least significant bit. In other words, 1000000 should be just No big deal. I was just thinking about it. I got a list of silly ideas on the computer, that are probably all in the same category. barry lotz wrote: > What I have done, and maybe others also, is to record a few channels at > varing gain ranges. With the speed of computers one can sample several That means another amp channel to buy though. Oh well. Maybe that's why Larry put three channels on each PCB, instead of Z, N, and E he meant High, Medium, and Low gain. ;) Thanks for all of the other comments. The last time I saw any of this at the electronics level was about eight years ago. We didn't go into that much detail either. ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: sensing quakes; accelerometers/seismometers Date: Sun, 18 Apr 1999 10:52:51 -0700 To add a note about seeing surface waves... I have talked to several people that claimed to see surface waves in the Colorado desert during events of the 1960's and 1970's. It seemed to be that they were seeing a wavefront marked by the effect of dust being kicked up into the air. In this desert region, I can imagine a lot of small dry hills and banks up to a meter or two high (stream channels, etc.) at or near the angle of repose -- just waiting for some small acceleration to set off a mini landslide and kick up some dust. A friend was working at a supermarket in El Centro, CA. during the 1968 Borrego Mountain M6.5 event. He said the effect inside the store was as if someone were running very fast down the isles of shelves with their hand scooping groceries onto the floor as they passed. He described a series of these wave fronts passing from the back to the front of the store, each one knocking more items onto the floor. Again, seeing the effect of the acceleration. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: Stacked chips Date: Sun, 18 Apr 1999 11:09:21 -0700 It seems that the accuracy (not precision) needed for seismic data points need not be better than 1% or so of the amplitude, regardless of the signal level. If this is so, with binary floating-point you could get by with one bit for sign, 7 bits for mantissa, and 5 bits for exponent, and cover the same range as a 32-bit linear A/D. You can always reconstruct the data later, subject to the accuracy limitation. Since the function is monotonic, I think you could still do it with a successive-approximation A/D algorithm, as Philip Schmidt described. Dedicate 16 bits to the job and you could do even better. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Re: PSN-L Digest for 17 Apr 1999 Date: Sun, 18 Apr 1999 11:28:11 -0700 "Dennis W. Pope" wrote: > I am installing a Guralp CMG-PEPPV. I realize this is near to heresy Please let us know how it works and all of the other details. ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Re: Stacked chips Date: Sun, 18 Apr 1999 15:20:27 -0400 Karl, Somewhere I read that integer data reconstructed that way behaves badly when you try to run it through a digital filter. I'd be interested in why that ought to be--sure not obvious. Brett >level. If this is so, with binary floating-point you could get by with one >bit for sign, 7 bits for mantissa, and 5 bits for exponent, and cover the >same range as a 32-bit linear A/D. You can always reconstruct the data >later, subject to the accuracy limitation. Since the function is >monotonic, I think you could still do it with a successive-approximation >A/D algorithm, as Philip Schmidt described. > >Dedicate 16 bits to the job and you could do even better. > > > >Karl Cunningham >La Mesa, CA. >PSN Station #40 >karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: wizard@......... (Rick Jerome) Subject: Re: DSP e-book Date: Sun, 18 Apr 1999 14:19:24 -0700 Thanks for the information. Highly recommend it to all. Am not a math expert here but found the discussions in chapter 9 great. >This is an e-book, full text, of a $60 book on DSP, written for people who >know nothing about DSP. >http://www.dspguide.com/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Wayne Abraham J73WA Subject: Statistics Date: Sun, 18 Apr 1999 22:31:48 -0400 PSN As most of you my well know, from September 1998 we, here in Dominica, have been experiencing numerous earthquakes. These quakes come in swarms which peak at up to 100 or more per day then disappear for a few days with only a few per day only to return a few days or weeks later with a large number of quakes. We have noticed a distinct relationship between the phases of the moon and the earthquake swarms but there are still many unanswered questions an wayward quakes. Some scientists have suggested that Dominica may be on a shallow level batholith which may account for our frequent shallow seismicity. If the batholith theory is true, I am speculating that it could be affected by the moon's gravitational pull. We, as a group, have decided to investigate the matter in greater detail. Being amateurs, there is not much more we can do than collect, analyze and compare data. We are searching for some sort of statistics software that would enable us to input the daily earthquake data from both the Government database and our recordings, moon phases and phase times, other major celestial and terrestrial phenomena like sun's angle and major earthquake activity along our plate. This data could be analyzed for any set pattern which may shed some light on the situation. Does anybody on this list have this type of software at their disposal or can lead us in the right direction? Thanks, Wayne. -- Wayne Abraham 1430 Rodney Street Portsmouth, Dominica abrahamw@........ http://www.freeyellow.com/members6/dominicapsn/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: unwanted oscillations Date: Sun, 18 Apr 1999 20:11:13 -0700 Karl, Sean Thomas et al I have set up a small vertical with triple feedback. I have been getting oscillations centered around 4 hz. FFT shows a nice "pyramid " around this value not a spike. My gain is very low (~42k). I set the vbb with Ri and Rp about 10x below the values STM uses, thinking I would provide more DC restoration current. Mathcad shows a quite rounded curve. Has anyone an idea what could be causing the "low freq" osc.? It is not evident from Mathcad. Regards Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: Statistics Date: Sun, 18 Apr 1999 20:43:04 -0700 (MST) On Sun, 18 Apr 1999, Wayne Abraham J73WA wrote: > We, as a group, have decided to investigate the matter in greater > detail. Excellent! > Being amateurs, there is not much more we can do than collect, > analyze and compare data. We are searching for some sort of statistics > software that would enable us to input the daily earthquake data from > both the Government database and our recordings, moon phases and phase > times, other major celestial and terrestrial phenomena like sun's angle > and major earthquake activity along our plate. This data could be > analyzed for any set pattern which may shed some light on the situation. > Does anybody on this list have this type of software at their disposal > or can lead us in the right direction? Wayne, The first thing you have to do is catalog your quakes. Then you can have all kinds of fun with the data. There are many sophisticated statistical techniques you can use to search for ~12 hr. periodicities in the data. The most difficult task is to deal with the background noise, and this can be done using several techniques, the best of which may be the random walk approach. I know a fellow that took laser data from the USGS after they were done processing it, applied the right statistical analysis, and is now able to show that the San Andreas fault slows down and speeds up, maybe in response to strain waves that might move through the lower crust. Anyways, enough babbling. There are several important things to decide in any seismicity analysis: 1) What is the lowest magnitude event you will consider? 2) What is your coverage for that magnitude, is your area of analysis reasonable based on this? 3) Will you weight the earthquakes with their magnitudes (i.e. moment release vs. time) or simply count them? As the next step, I suggest you try to gather as large a catalog as you possibly can, then do a fourier transform of the data. If your hypothesis is correct, then you should see an increase in activity at around 12.5 hr or 0.5 day frequencies. If you do not see anything special, then you can consider "smoothing" your data and looking at it again. The simplest way to smooth the data is to use a "time window" and average the values in a pre-defined interval before and after the time you are interested in looking at. To avoid interference with your sought after 12 hr peak you should choose window values of 30 min to 2 hrs. This means that for the data value at time "t", you average all the events within half the window size before and after t. Try looking at different window sizes, and see what happens. If you still cannot find periodicity in the fourier transform, then more sophisticated guns can be used to search for it. The best way to do this type of analysis is via "fortran" or some other numerical code. The moon's position is very well known, but the data will say whether it is worth the trouble of getting more in this way. I will be happy to either forward you copies of all my relevant fortran codes or run this analysis for you on our computer. I'll be happy to help in whatever way possible. I like the idea of the PSN also doing science with their data. I do have a few theory questions for you: what is it mechanically that would make the seismicity more prone to tides when it is associated with a shallow batholith rather than a deeper one? John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Re: unwanted oscillations Date: Mon, 19 Apr 1999 00:17:51 -0400 Barry, From what you say, although your "system" gain is lower, because Ri & Rp are low, the gain *around* the loop is now a lot higher = more likely to oscillate. I'd expect the oscillation to be between 50 - 90 Hz, though what you're describing sounds more like a relaxation oscillation, where the loop oscillates, causing something to get overloaded, so the oscillation stops, then the overloaded stage slowly recovers and the oscillation starts up again.... repeat 4 x per second. That could also explain the funny FFT. An oscilloscope should make it very obvious what's happening. That kind of oscillation usually looks sort of sawtooth-shaped. Don't think it's a good idea to make big changes in those feedback values, To make things work you'd also need to make other mods to keep the loop gain curve pretty much unchanged at frequencies over about 4Hz, and It's not obvious whether that would be very easy to do. Now that I think a little more about it, I'm not sure if Ri and Rp are going to have a big effect above 4Hz. One would need to take a more careful look at the loop gain plot to see what's going on. The reason the problem might not show up in Mathcad is that the things that are directly causing the oscillation are a number of fairly high frequency poles that we have normally chosen to ignore. I would assume your model doesn't have any poles above 5 Hz, though for sure they are there. If you found them and put all of them into the model, I'd bet the calculation would then predict an unstable loop. Brett At 08:11 PM 4/18/99 -0700, you wrote: >Karl, Sean Thomas et al > I have set up a small vertical with triple feedback. I have been >getting oscillations centered around 4 hz. FFT shows a nice "pyramid " >around this value not a spike. My gain is very low (~42k). I set the vbb >with Ri and Rp about 10x below the values STM uses, thinking I would >provide more DC restoration current. Mathcad shows a quite rounded >curve. Has anyone an idea what could be causing the "low freq" osc.? It >is not evident from Mathcad. > >Regards >Barry > > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Bonnie Schafer" Subject: Re: sensing quakes; accelerometers/seismometers Date: Sun, 18 Apr 1999 20:01:31 -0700 Hi, in 1971 I experienced sensations like I was on a rolling ship and you could feel the waves and the ground actually seemed to be rippling. Have never felt that sensation in any of the quakes I have been through since then. Bonnie the crafty crafter _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Walt Williams" Subject: PSN-L: Re: sensing quakes; accelerometers/seismometers Date: Sun, 18 Apr 1999 22:37:58 -0800 All, "To add a note about seeing surface waves..." In the 1971 San Fernando (California, USA) earthquake, I observed the grassed lawn in my front yard move similar to ocean waves. The waves appeared two to three feet across and about one foot high and guessing maybe 15 per minute if event had lasted that long. The yard did not crack. In the same area of the yard I also observed a thirty foot tall tree slap the ground on either side similar to a fly swatter. Fascinating and quite exciting. Best Wishes, Walter Williams, 99.04.18 OSR PSN Stn #63 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Bill Combs" Subject: RE: sensing quakes; accelerometers/seismometers Date: Mon, 19 Apr 1999 08:15:29 -0500 Dear Bonnie, I happened to see your message in my husband's listserve message and I was wondering why you were talking about these sensations with my husband. I know where he was in 1971, but where were you? Near Purdue? Near his Army basic training camp? and just what kind of crafter are you, dear Bonnie? I actually felt a tremor in southern Indiana in April, 1974, which happened to be the day of the largest outbreak of tornadoes in this state in recorded history. I always wondered if there was a connection. By the way, do you read lots of books with cheesy beefcake pictures of half-clad fake butter salesmen on the front? (Hey, I gotta do something to keep my sanity.)I just wondered because your message sounded like something I read in connection with a bodice ripping man of the sea once. Dianne the haphazard quilter and fulltime mommy. > -----Original Message----- > From: Bonnie Schafer [mailto:bschafer@.......... > Sent: Sunday, April 18, 1999 10:02 PM > To: PSN-L Mailing List > Subject: Re: sensing quakes; accelerometers/seismometers > > > Hi, in 1971 I experienced sensations like I was on a rolling ship and you > could feel the waves and the ground actually seemed to be rippling. Have > never felt that sensation in any of the quakes I have been through since > then. > > Bonnie the crafty crafter > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: GeE777@....... Subject: Re: Statistics Date: Mon, 19 Apr 1999 11:52:37 EDT In a message dated 4/18/99 7:38:20 PM Pacific Daylight Time, abrahamw@........ writes: > We have noticed a distinct relationship between > the phases of the moon and the earthquake swarms Wayne I find this interesting. Keep a spreadsheet record of moon phase, high/low tide levels and number and or intensity of seismic events per day. Then plot them to see the relationship. What phase of the moon do you have most of your events? Regards, George Erich Seismic Exploration Consultant P. O. Box 2011, Norwalk, CA 90651, U. S. A. Phone (562) 868-6013 e-mail GeE777@....... 33 53.90N 118 04.53W J _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: GeE777@....... Subject: Re: Statistics Date: Mon, 19 Apr 1999 11:52:37 EDT In a message dated 4/18/99 7:38:20 PM Pacific Daylight Time, abrahamw@........ writes: > We have noticed a distinct relationship between > the phases of the moon and the earthquake swarms Wayne I find this interesting. Keep a spreadsheet record of moon phase, high/low tide levels and number and or intensity of seismic events per day. Then plot them to see the relationship. What phase of the moon do you have most of your events? Regards, George Erich Seismic Exploration Consultant P. O. Box 2011, Norwalk, CA 90651, U. S. A. Phone (562) 868-6013 e-mail GeE777@....... 33 53.90N 118 04.53W J _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Re: Stacked chips Date: Mon, 19 Apr 1999 09:13:09 -0700 Floating point digitizers... used to be the standard method in exploration seismographs. You put an amplifier in front of the A/D converter, one that has gain steps in powers of two. Then you put a signal level detector on the output of the amplifier that looks at the signal and adjusts the amplifier gain so that the output is somewhere around half to 3/4 of full scale on the A/D converter. You do this really fast, so the gain adjustment happens prior to every sample of the A/D converter. Then, you record the A/D output and the amplifier gain that was used. The A/D signal becomes the mantissa and the gain becomes the exponent. Now, you can handle a very wide range of signals without clipping, certainly a lot more than your preamp can handle. I hesitated to use the word dynamic range here, even though that is commonly done. Suppose you use an 8-bit A/D in this device. You can record really big signals and really small signals, but not at the same time, because you only have 8-bits of resolution. Sometimes we use the words "instantaneous dynamic range" to describe that number, sometimes we say resolution. In seismic reflection, this is a big issue because small reflections will be buried in big surface waves, and we need resolution to pull those signals out using various DSP methods. The difference between dynamic range and resolution are the reasons these numbers don't always process well. Resolution is also a measurement of distortion. In processing, it is common to just plug these numbers into a 32-bit fixed-point number because they are faster to handle than true floating point. You just shift the mantissa up or down depending on the gain. I am not an expert on processing earthquake data, but I would guess that you would want more than 8-bits of resolution to do signal processing. On the other hand, if your interest is getting nice seismographs, an 8-bit floating point digitizer would be great, since you can never see more than 8-bits on a plotted record. If you start filtering out sea swells, it might be a concern. Of course, 24-bit converters are preferred because they are linear and monotonic, distortion is low, and data processing works very well. In practice, a cheap compromise is to use one of those low-cost audion A/D's and put a single step amplifier in front, maybe 12-db. If you want to get elegant, run the cheap A/D at high speed and then decimate the data down to a lower speed with real time digital low-pass filter. -- Doug Crice web site http://www.georadar.com GeoRadar Inc. e-mail dcrice@............ 19623 Via Escuela Drive phone 408-867-3792 Saratoga, CA 95070 USA fax 408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: PSN-L Digest for 17 Apr 1999 Date: Mon, 19 Apr 1999 11:05:47 -0600 (MDT) Dennis Pope writes: "I am installing a Guralp CMG-PEPPV." Dennis, How much did this instrument cost you? Thanks, JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Wayne Abraham J73WA Subject: Re: Statistics Date: Mon, 19 Apr 1999 16:39:00 -0400 George When Ed Cranswick and his friend were on Dominca, we had a small swarm on Boxing Day (First quarter) which declined a little then intensified the day after the left, New Years day (full moon). These quakes seem to be showing up at full and new moons and sometimes at a quarter. It may be coincidence but after a period of relative quiet, we had a few more quakes on April 08 and April 16 - last quarter and new moon respectively. Wayne GeE777@....... wrote: > In a message dated 4/18/99 7:38:20 PM Pacific Daylight Time, > abrahamw@........ writes: > > > We have noticed a distinct relationship between > > the phases of the moon and the earthquake swarms > > Wayne > > I find this interesting. Keep a spreadsheet record of moon phase, high/low > tide levels and number and or intensity of seismic events per day. Then plot > them to see the relationship. What phase of the moon do you have most of > your events? > > Regards, > > George Erich > Seismic Exploration Consultant > P. O. Box 2011, Norwalk, CA 90651, U. S. A. > Phone (562) 868-6013 > e-mail GeE777@....... > 33 53.90N > 118 04.53W > J > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Wayne Abraham 1430 Rodney Street Portsmouth, Dominica abrahamw@........ http://www.freeyellow.com/members6/dominicapsn/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Real Seismograph Date: Mon, 19 Apr 1999 15:15:49 -0700 An interesting "seismograph" on ebay.com at http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=93177543 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: Stacked chips Date: Mon, 19 Apr 1999 19:13:22 -0700 Hi Doug I was thinking the same thing last night. I have done it two ways, with a analog multiplexer w/resistor ladder and with a programmable gain opamp or instrument. amp. I set two thresholds, one at ~10% for gain increase by two and one about 80% for decreasing the gain by two. I kept track of the gains in a separate integer array and when an event was triggered, I whent thru the whole array and "normalized" the event for the lowest gain setting(highest reading). In assembly language it goes fast. I stopped doing this data acquisition method when I implimented digital filtering because I wasn't sure how to do both in real time. Regards Barry Doug Crice wrote: > Floating point digitizers... > > used to be the standard method in exploration seismographs. You put an > amplifier in front of the A/D converter, one that has gain steps in > powers of two. Then you put a signal level detector on the output of > the amplifier that looks at the signal and adjusts the amplifier gain so > that the output is somewhere around half to 3/4 of full scale on the A/D > converter. You do this really fast, so the gain adjustment happens > prior to every sample of the A/D converter. Then, you record the A/D > output and the amplifier gain that was used. The A/D signal becomes the > mantissa and the gain becomes the exponent. Now, you can handle a very > wide range of signals without clipping, certainly a lot more than your > preamp can handle. > > I hesitated to use the word dynamic range here, even though that is > commonly done. > > Suppose you use an 8-bit A/D in this device. You can record really big > signals and really small signals, but not at the same time, because you > only have 8-bits of resolution. Sometimes we use the words > "instantaneous dynamic range" to describe that number, sometimes we say > resolution. In seismic reflection, this is a big issue because small > reflections will be buried in big surface waves, and we need resolution > to pull those signals out using various DSP methods. > > The difference between dynamic range and resolution are the reasons > these numbers don't always process well. Resolution is also a > measurement of distortion. > > In processing, it is common to just plug these numbers into a 32-bit > fixed-point number because they are faster to handle than true floating > point. You just shift the mantissa up or down depending on the gain. > > I am not an expert on processing earthquake data, but I would guess that > you would want more than 8-bits of resolution to do signal processing. > On the other hand, if your interest is getting nice seismographs, an > 8-bit floating point digitizer would be great, since you can never see > more than 8-bits on a plotted record. If you start filtering out sea > swells, it might be a concern. > > Of course, 24-bit converters are preferred because they are linear and > monotonic, distortion is low, and data processing works very well. > > In practice, a cheap compromise is to use one of those low-cost audion > A/D's and put a single step amplifier in front, maybe 12-db. If you > want to get elegant, run the cheap A/D at high speed and then decimate > the data down to a lower speed with real time digital low-pass filter. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Bonnie Schafer" Subject: Re: sensing quakes; accelerometers/seismometers Date: Mon, 19 Apr 1999 19:34:10 -0700 Hi, well I was in Southern CA about 50 miles for the epicenter of the quake that struck in February of 1971. That was the first big quake I had experienced since coming to CA in 1966. I like to knit, crochet and am dabbling in beadwork. Bonnie the crafty crafter _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Unknown Subject: From: Unknown Subject: From: Unknown Subject: From: Brian Chesire Subject: New Accelerometer Date: Tue, 20 Apr 1999 17:43:18 -0700 Ran into a new type of accelerometer while looking for some rate sensors today at work. It's the Humphrey LA01 and LA02 single and two axis device. They apparently operate on thermal convection, with a range of plus and minus 1 G. Noise is bit high 30 micro G rms from 0.1 to 1 Khz and 10 micro G per root Hz, from 1 to 1kHz. The frequency response is 0 to 4 Hz, compensatable to 30 Hz. Should be a lot better than the Analog Devices accelerometers. Humphrey is now a susidiary of REMEC and their web site has no tech data yet. I found a data sheet at, http://fqs.dconn.com/index.asp Any one think it's worth playing with? Brian WA5PPO Tucson, AZ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: integrators Date: Tue, 20 Apr 1999 20:00:37 -0700 Karl I have been thinking of force balance sensors for a long time. What stopped me was in measuring acceleration and integrating it to velocity in hardware.As I understand it an integrator has the cap in the feedback loop. The gain of the integrator increases by 6db as the frequency is lowered. To limit the gain , a resistor is put in the feedback loop also. The cap/input resistor determine the freq @ unity gain and the feedback resistor/cap determine the freq below which the integrator is limited and becomes an amplifier. You have posted wonderful events. Does this varing response of an integrator complicate and modify the response? Have you tried to measure your sensors output vs frequency? Regards Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Bonnie Schafer" Subject: my apologies Date: Tue, 20 Apr 1999 20:10:53 -0700 I am sorry that my last message went to the whole list it was meant to be a personal reply. Bonnie the crafty crafter _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: New Accelerometer Date: Tue, 20 Apr 1999 21:40:35 -0700 Brian, This sensor has been brought up before... It has two major problems, its not sensitive enough for teleseismic events, and, it doesn't have a high enough frequency response for local events. Not sure how well it "compensates" to 30hz... -Larry Cochrane Redwood City, PSN At 05:43 PM 4/20/99 -0700, you wrote: >Ran into a new type of accelerometer while looking for some rate sensors >today at work. It's the Humphrey LA01 and LA02 single and two axis >device. They apparently operate on thermal convection, with a range of >plus and minus 1 G. Noise is bit high 30 micro G rms from 0.1 to 1 Khz >and 10 micro G per root Hz, from 1 to 1kHz. The frequency response is 0 >to 4 Hz, compensatable to 30 Hz. Should be a lot better than the Analog >Devices accelerometers. Humphrey is now a susidiary of REMEC and their >web site has no tech data yet. I found a data sheet at, > > http://fqs.dconn.com/index.asp > >Any one think it's worth playing with? > >Brian WA5PPO >Tucson, AZ > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: VBB component values Date: Wed, 21 Apr 1999 01:31:48 -0500 (CDT) Barry, Karl, Brett and co. Several questions regarding the VBB feedback have come up. Re. Barrys recent question about the behavior of the integrator: The integrator is a single pole low-pass filter with a gain inversely proportional to the frequency. It does NOT have to have the capacitor in the feedback loop (this is a leftover from very early op-amps that were unstable if the non-inverting input was used). The integrator works just as well with a high-value input resistor coupling to a high-value capacitor to ground at the non-inverting input (these make up the integrator time constant). With a non-inverting unity gain configuration, the feedback resistor is the same as the input resistor; for use in the VBB feedback, the signal cannot be amplified or inverted. The frequency response is essential for the VBB response and is part of the transfer function. For the experimental multi-period VBB, I am using integrator time constants of 10, 40, and 80 seconds, using resistors of 1, or 2 meg ohms and capacitors of 10,20,and 40ufarad. THe only way I can address the question about the resulting response is to point to the calibration data on my web site, where the independent calibration data overlay the response predicted by the transfer function. WHat you see is what you get. Regarding the question of using lower displacement gain "r" and a much larger feedback capacitor Cp: Naturally, you can plug any range numbers into the transfer function and get any response you want. Decreasing r by 1/50 and increasing Cp by x50 and adjusting the damping can give a flat response. However, lowering r really lowers the high frequency corner, and seismologists really want something flat to above 50 hz., or at least well above the anti- aliasing filters of the digitizer. Reducing r and increasing Cp causes a serious reduction of the net output (by 1/20 or more). This means that an amplifier that adds noise and probably compromises the dynamic range needs to be put ahead of the digitizer. One of the major plusses of a VBB instrument is that the passive-component feedback results in an inherent dynamic range of 120db or more which is not limited by amplifiers. For reference, for the multi-period design I am using a VRDT with 200 millivolts/micron, a 10x amplifier, for an r of 2 000 000 volts/meter. With Cp set to 20 uf for all periods, the output is 2100 volts/meter/second, and the -3db upper frequency corner is at 80hz. Also, decreasing r really limits the sensitivity to detecting small accelerations, increasing the noise floor. And if Cp is too large, it can cause short-period oscillations. Making the mass large doesn't help either; the brownian noise of 0.3kg is below the low noise model for any reasonable period and Q. Put as a simplistic concept, a smaller mass is "easier" for the feedback system to "control". Commercial VBB masses range from 0.6 to less than 0.1 kg. You have suggested that you are using 500ufarad with r = 42 000. Unless you have won the lottery, I assume that this is a pair of 1000 uf electrolytics. The biggest problem in using a large Cp is that non-polarized electrolytics are not acceptable for the feedback components. They are very temperature sensitive in regard to value and leakage. Polypropolyne or polystyrene are needed. The leakage of these is 10^5 megohm-microfarads or more; electrolytics have a value as little as 1, and being electro-chemical cells, are very temperature dependent. And since the dielectric layer is formed by the imposition of voltage, it degrades with time, or the actual capacitance varies with the voltage and frequency. If you look under the hood of the feedback box of a Streckheisn, it is packed with an array of pricey cubical 10uf poly capacitors, all measured. Years ago, I got into a discussion with Mr. Guralp about using tantalum capacitors in the feedback. THere was a problem with instability with temperature change as the Cp change made the feedback unstable. As far as I can see, poly caps are used for both the feedback and the integrator C in all the commercial instruments. You asked about oscillations around 4hz. Aside from the above considerations, a value we like to ignore is the presumably quite short time constant of the displacement detector amplifier. It naturally does have some low-pass filtering with associated phase shifts. My original VBB audibly hummed at about 400 hz until I added a small RC filter to the amplifier input. I used a decade resistor to tweak it until the oscillation stopped, with something like 1200 ohms into 4 uf, which I presume was making a phase correction. Maybe Brett can shed some light on this. Regards, Sean-THomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: integrators Date: Wed, 21 Apr 1999 08:47:09 -0700 Barry, Your description of the integrator is correct. Since the integrator is integrating acceleration to velocity, the low-frequency limit of the integrator (set by the resistor in the feedback) makes it act like a high-pass filter for velocity signals. Below this cutoff frequency, it is flat to acceleration and velocity rolls off at 6db/octave as frequency DECREASES. Above this cutoff, it is flat to velocity and acceleration rolls off at 6db/octave as frequency INCREASES. I think one of the keys to producing good looking seismograms is to limit the bandwidth at both the high and low ends. My system uses third-order Bessel filters (which have little overshoot) to filter the upper and lower ends of the response. My system has two velocity outputs -- one with a passband of 0.1Hz to 5Hz for local events and the other with a passband of 0.01Hz to 0.5Hz for teleseismic events. I think the way to go these days is the VBB design. It is a force-balance system but takes its output from a different point in the circuit than mine does. In both systems, the current through the feedback coil is proporational to acceleration. My approach takes this velocity signal and integrates it to velocity. The VBB approach is at bit more elegant, as it doesn't use the integrator stage in the output. This is my understanding of how the VBB works... It takes advantage of the fact that over the passband of interest the feedback path from the displacement transducer differentiates the signal on its way to the feedback coil. This means that the signal at the displacement transducer is the integral of that at the feedback coil. Since the signal at the feedback coil is proporational to acceleration, the output of the displacement transducer is the integral of that, which is velocity. When I first built it, I measured my instrument's response to acceleration using the meter-movement calibrator described on this list by Bob Barns. I didn't have a way to excite the system with a velocity input, but the response to acceleration was as expected. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... At 11:11 PM 4/20/99 -0700, you wrote: > Karl > I have been thinking of force balance sensors for a long time. What >stopped me >was in measuring acceleration and integrating it to velocity in hardware.As I >understand it an integrator has the cap in the feedback loop. The gain of the >integrator increases by 6db as the frequency is lowered. To limit the gain , a >resistor is put in the feedback loop also. The cap/input resistor determine >the >freq @ unity gain and the feedback resistor/cap determine the freq below >which the >integrator is limited and becomes an amplifier. > You have posted wonderful events. Does this varing response of an >integrator >complicate and modify the response? Have you tried to measure your sensors >output >vs frequency? > Regards >Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: CARRJJ@....... Subject: Re: integrators Date: Wed, 21 Apr 1999 18:04:20 EDT Overall the integrator is a low-pass filter, not a high pass filter. You are speaking only of the portion in the feedback loop. The "standard" textbook op-amp integrator uses a resistor in the inverting input, and a capacitor in the feedback loop (noninverting input grounded). The gain is 1/RC x (integral input voltage dt), so with some values of R and C the gain gets huge in a hurry. Also, the "standard" circuit doesn't work well unless the op-amp has a very low input offset current and output offset voltage. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Re: integrators Date: Wed, 21 Apr 1999 19:03:19 -0700 The circuit with the capacitor in the feedback loop is a true integrator. The input voltage divided by R sets the current that charges the capacitor, and thus the voltage across the capacitor equals - the integral of voltage over time. Sean's circuit where the resistor goes to the non-inverting input and the capacitor goes to ground is not a true integrator because the charging current is proportional to the difference between the input voltage and the capacitor voltage. As the capacitor charges up towards the input voltage, the current drops asymtopically to zero. This circuit is actually a one-pole low-pass filter with a time constant of RC. F = 1/(2piRC) However, for small signals, the circuit approximates an integrator, and would be rock solid stable. The integrator would require a resistor in parallel with the capacitor, which means that it's not a true integrator either, but would behave like one for some range of frequencies where the feedback resistor is large. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: tornado seismic noise Date: Wed, 21 Apr 1999 19:04:07 -0700 (MST) On Sat, 17 Apr 1999, S-T Morrissey wrote: > Tornadoes are an atmospheric phenonemon and impart very little > energy into the ground that a seismic instrument might record at > at a sufficient distance such that several seismometers would sense > the event so that it could be located or tracked. Sean, would you say that most of this signal comes directly from the wind blowing on the seismometer housing or shelter? It is hard to imagine any significant transmission of energy from the wind to the ground except via trees or buildings rocking (or exploding in the case of some tornados). > I did see the noise from the VBB sensor in the basement, as well as > in the telemetered data from the station in the back field. But no > other stations recorded it. And if I had not known about the tornado, > (I was sitting here watching it), I would not have suspected that > the noise was anything other than a localized strong wind. Do you think a horizontal would have picked up more? The force couple of wind to ground seems to be more horizontal... John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: New Shishaldin Eruption .... marked increase in level of activity on Date: Wed, 21 Apr 1999 21:35:26 -0700 (MST) This activity is picking up! Check weather satellites for the region (Aleutians) to see the ash plume leaving the volcano...good stuff. > ---------- > From: Dan Shackelford > Sent: Monday, April 19, 1999 9:40 PM > Subject: New Shishaldin Eruption .... marked increase in level of > activity on 19 April >=20 > Following two months of heightened seismicity and a steady new thermal > anamoly, Alaska's Shishaldin volcano has begun a new eruptive episode. > Strombolian eruption began on 17 April 1999 with spattter and glowing > blocks rising up to 200m a.c. (above crater). In the morning that day lav= a > was seen at the summit crater but was not overflowing, although snowmelt > was obvious down the NW flank; no lava was seen later that evening. > However, activity has rapidly intensified on 19 April, and as of midday o= n > the 19th, an ash plume rising to 30,000 feet above sea level (~9km asl) > was > in evidence, and there has been a dramatic increase in tremor amplitude a= s > well. A significant eruption is now occurring at this volcano and the > Alert > Level has been raised to RED. >=20 >=20 > Following from: http://www.avo.alaska.edu/avo3/volc/shish/1999_unrest.htm= l >=20 > URGENT > ALASKA VOLCANO OBSERVATORY > INFORMATION RELEASE > Monday, April 19, 1999 12:15 PM ADT (2015 UTC) >=20 > SHISHALDIN VOLCANO > 54=B045.33' N 163=B058.00' W > Summit Elevation 9373 ft (2857 m) > Current Level of Concern Color Code: RED > Previous Level of Concern Color Code: ORANGE=20 >=20 > A pilot report at 11:45 am indicates that a steam-and-ash plume from > Shishaldin Volcano has reached 30,000 ft. Tremor amplitudes have also > dramatically increased since 11:33 and have started showing up at more > distant stations, after a steady increase in tremor levels over the last > two days. A significant eruption is occurring, and we are raising our > Level > of Concern Color Code for a Shishaldin to RED.=20 >=20 > A low-level strombolian eruption was first observed Saturday at Shishaldi= n > volcano at 5:00pm ADT by AVO staff flying in the area with the Alaska > State > Troopers. Incandescent blocks and spatter were erupting as high as 200m > above the vent but at that time no lava had come over the crater rim. > National Weather Service (NWS) observers in Cold Bay and a NWS ship in th= e > area this morning reported seeing incandescent lava at the summit of the > volcano and snowmelt running partway down the NW flank. Ash clouds presen= t > significant hazards to aircraft flying over this part of the Aleutians, > and > may also cause minor ash falls in nearby communities. Mudflows down the > volcano flanks would be dangerous to hikers in the area and could be > generated at any time.=20 >=20 > AVO staff is monitoring the eruption 24 hrs a day with real-time seismic > and satellite data and further updates will be issued as new information > becomes available.=20 >=20 > Shishaldin volcanic has been in a state of unrest since early February an= d > is one of the most active volcanoes in the Aleutian arc, erupting at leas= t > 27 times since 1775. The previous eruptive period occurred in late 1995 > and > early 1996 and consisted of minor explosions that produced low-level stea= m > and ash emissions. Shishaldin volcano is located near the center of Unima= k > Island in the eastern Aleutians. The spectacular symmetric cone has a bas= e > diameter of approximately 10 miles (16 km) and a small summit crater that > typically emits a steam plume with occasional small amounts of ash.=20 >=20 >=20 >=20 > -------------------------------------------------------------------------= - > -- > ALASKA VOLCANO OBSERVATORY > INFORMATION RELEASE > Sunday, April 18, 1999 10:00 AM ADT (1800 UTC) >=20 > SHISHALDIN VOLCANO > 54=B045.33' N 163=B058.00' W > Summit Elevation 9373 ft (2857 m) > Current Level of Concern Color Code: ORANGE=20 >=20 > A low-level strombolian eruption was first observed yesterday at > Shishaldin > volcano and 5:00pm ADT by AVO staff flying in the area with the Alaska > State Troopers. Incandescent blocks and spatter were erupting as high as > 200m above the vent but at that time no lava had come over the crater rim= =2E > National Weather Service (NWS) observers in Cold Bay and a NWS ship in th= e > area this morning reported seeing incandescent lava at the summit of the > volcano and snowmelt running partway down the NW flank. Mudflows down the > volcano flanks would be dangerous to hikers in the area and could be > generated at any time. A small steam plume with little or no ash is being > generated as hot lava contacts snow at the summit of the volcano. The > eruption could reach a phase in which small explosions could produce a > small low level ash plume. This type of eruption could continue for weeks > to months. >=20 > Tremor seismicity continues at an elevated level and the thermal anomaly > observed by satellite imagery persists. AVO staff is monitoring the > eruption 24 hrs a day with real-time seismic and satellite data and > further > updates will be issued as new information becomes available. >=20 > Shishaldin volcanic has been in a state of unrest since early February an= d > is one of the most active volcanoes in the Aleutian arc, erupting at leas= t > 27 times since 1775. The previous eruptive period occurred in late 1995 > and > early 1996 and consisted of minor explosions that produced low-level stea= m > and ash emissions. Shishaldin volcano is located near the center of Unima= k > Island in the eastern Aleutians. The spectacular symmetric cone has a bas= e > diameter of approximately 10 miles (16 km) and a small summit crater that > typically emits a steam plume with occasional small amounts of ash. >=20 >=20 > o o o o o o o o > > > > > danshack@............. > o _____________________________=20 > o _____ | |=20 > .][__n_n_|DD[ =3D=3D=3D=3D_____ | |= =20 > >(________|__|_[_________]_|___________________________| > _/oo OOOOO oo` ooo ooo 'o!o!o o!o!o`=20 > -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ***************************************************************************= *** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Stephen Caruso" Subject: Re: tornado seismic noise Date: Thu, 22 Apr 1999 00:47:54 -0400 "Bob Vincent at Bowling Green and Attila Kilinc at U.of Cincinnati are working on this problem. We did get a signal from the Cincinnati station coinciding in time with the April 9 tornado--that is, when it was on the ground....would appreciate any information that you come across. " Mike Hanson ODNR This was a #4 on scale of tornadic activity. Stephen Caruso -----Original Message----- From: John Hernlund To: PSN-L Mailing List Date: Wednesday, April 21, 1999 10:10 PM Subject: Re: tornado seismic noise >On Sat, 17 Apr 1999, S-T Morrissey wrote: >> Tornadoes are an atmospheric phenonemon and impart very little >> energy into the ground that a seismic instrument might record at >> at a sufficient distance such that several seismometers would sense >> the event so that it could be located or tracked. > >Sean, would you say that most of this signal comes directly from the wind >blowing on the seismometer housing or shelter? It is hard to imagine any >significant transmission of energy from the wind to the ground except via >trees or buildings rocking (or exploding in the case of some tornados). > >> I did see the noise from the VBB sensor in the basement, as well as >> in the telemetered data from the station in the back field. But no >> other stations recorded it. And if I had not known about the tornado, >> (I was sitting here watching it), I would not have suspected that >> the noise was anything other than a localized strong wind. > >Do you think a horizontal would have picked up more? The force couple of wind >to ground seems to be more horizontal... > >John Hernlund >E-mail: hernlund@....... >WWW: http://www.public.asu.edu/~hernlund/ > >*************************************************************************** *** > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: wind noise Date: Wed, 21 Apr 1999 23:57:43 -0500 (CDT) John, I think that the wind can impart energy to the earth just as it couples energy into lakes or oceans creating waves. The earth is quite elastic with low attenuation at low frequencies. I suppose an example would be the wind noise we dealt with in the Aleutians. There are no trees or structures there, and our stations were at least a kilometer from the ocean and at several hundred feet elevation. We would see differences in the wind noise depending on the storm track, probably due to the influence of local topography. Of course the short (3 meter) antenna mast would make noise, but it was always anchored to rock several tens of meters from the seismometer package, and its oscillation frequency was much higher than the usual wind noise of 2hz to a few seconds. Some sites had a particular natural peak in the wind nose period that we suspected was due to a resonance of a nearby tundra bog. The horizontals were more sensitive to wind noise due to tilting of the ground from differential pressure loading. In fact, we recorded all the horizontals (each site has one EW sensor) at 1/2 the gain of the verticals because of this. As I mentioned before, the attenuation was sufficient that wind noise at one site would be barely visible at a site 10 km away. Of course, the rocky volcanics would attenuate the signal much more than say the flat sedimentary structures of the midwest. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: VBB component values Date: Wed, 21 Apr 1999 22:24:31 -0700 Sean ,Karl, Joe and Doug Thanks all for your comments. I guess measuring the response of a sensor to frequency changes is ultimately the test. One might even be able to make the equivalent of a lookup table to get a better response curve,assuming one can calibrate the system reasonably accurately. I have yet to use Bob Barns' calibrator. I think the oscillations I'm sensing are probably caused from the large, poor quality, Cp and the lack of ability of the weaker coil/magnet (3.8 N/A) to control the larger mass (1kg). I'll adjust and see what happens. Regards Barry ---snip--- > Also, decreasing r really limits the sensitivity to detecting small > accelerations, increasing the noise floor. And if Cp is too large, it > can cause short-period oscillations. Making the mass large doesn't help > either; . Commercial VBB masses range from 0.6 to less than 0.1 kg. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "James M Hannon" Subject: Re: tornado seismic noise Date: Thu, 22 Apr 1999 10:19:51 -0500 There was some mention on this list of a conference on detecting tornados with seismographs last year. I don't remember hearing anything about the outcome of that conference. What I suspect is that someone thought it might be possible to put an already existing seismic network to double duty by using it for detecting tornados. Assuming it would work and you could get the data from the network fast enough for it to be of any use in warning people of the tornado. This web site http://www4.etl.noaa.gov/infra/infrasonic.html indicates that there is an overlap in the frequencies generated in the air by tornadoes and earthquake frequencies. Getting double duty out of a network of sensors is a good idea but I am thinking that a network of accoustic sensors would be much better at detecting tornados than a seismic network. Jim hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Re: integrators Date: Thu, 22 Apr 1999 12:04:30 -0400 Doug, I agree with your analysis of the feedback integrator circuit. It does seem to approximate a true integrator with a pole at zero frequency. That circuit was interesting to me, too, as it also seemed to allow for using a smaller integrating capacitor. It appears that the limiting factor might be the current noise of the op-amp, but there seem to be a number that may be good enough. My goal is to be able to use something around 2uF, though that may have to go larger. Like you, I'd thought you would have to have a resistor in parallel with the capacitor to keep the circuit from slowly drifting out of range. Karl had argued that you don't need that, and try as I might, I can't demonstrate to myself why you do. With the loop active, the feedback should act to keep things under control. The only difficulty could be that the input resistor may need to be pretty large; you'd possibly want to put grounded guard rings on the circuit board around the I.C. input lead and use some good shielding. It should be easy to set up the circuit to duplicate the frequency response of the present one, with the single exception that its low frequency pole will have been moved back to zero. Brett At 07:03 PM 4/21/99 -0700, you wrote: >The circuit with the capacitor in the feedback loop is a true >integrator. > >However, for small signals, the circuit approximates an integrator, and >would be rock solid stable. > >The integrator would require a resistor in parallel with the capacitor, >which means that it's not a true integrator either, but would behave >like one for some range of frequencies where the feedback resistor is >large. > > >_____________________________________________________________________ > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: GPS position question Date: Thu, 22 Apr 1999 12:59:26 -0700 (MST) On Sat, 17 Apr 1999, Larry Cochrane wrote: > Does anyone know what type of position accuracy one can expect from a GPS > receiver with long term data averaging? Besides time information, SDR also > gets position info. I added some code to SDR to take the position info, > sampled every 15 minutes when SDR asks for time info, and creates a running > average of the latitude, longitude and height of the GPS receiver. The user > can then save this info in a file by pressing the "g" key. Larry, One would think that if the error were randomly scattered about the "real" position that a long term average should approach a more accurate mean. But the satellite tracks and such are not random as far as I know, and this might introduce some systematic error into the average... If the systematic error is simple in nature, then maybe it can be removed by relatively simple statistical techniques. It would be interesting to plot all the data you get into a "cloud" plot and see what it looks like. If it is elliptical, then correction should not be too hard... John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: angel rodriguez Subject: Re[2]: GPS position question Date: Thu, 22 Apr 1999 15:47:20 -0500 Hi John, I was asking the same questions a while back and while almost every one agreed that about 25 meters was the best one could do here is the best of the answers I got. From: "Peter H. Dana" To: "'Angel Rodriguez'" Subject: RE: Question Date: Sat, 20 Feb 1999 17:32:33 -0600 Angel: Thank you for your interest in the Geographer's Craft GPS Overview. Not really goofy - you can certainly do that - and long term averaging will reduce those GPS errors that average to zero - but the trouble is the two biggest errors don't average to zero - often even after many weeks. Selective Availability and the ionospheric errors are biases that change all the time. So an average taken over one week might well differ by several meters from an average taken over another week. But - this is not the real problem - you might even find that for four weeks in a row you got the same value, there is no guarantee that the fifth week or even the second month will be the same. Usually agreement to ten meters is possible from week to week - but rarely better than that. You also have no way to evaluate the answer - So tectonic drift is done using networks of carrier phase receivers that use L1- and L2 to measure the ionosphere and special precise ephemeris sets rather than broadcast orbital data. Peter Peter H. Dana - Department of Geography - University of Texas at Austin Austin, Texas 78712-1098 - Tel: (512) 869-1450 - Fax: (512) 869-0899 -----Original Message----- From: Angel Rodriguez [SMTP:angelr@............. Sent: Saturday, February 20, 1999 2:39 PM To: pdana@............... Subject: Question Hi, This may be a goofy question, but here goes. If I read the output from my cheap gps receiver into a computer and average the reading over weeks and months, just how accurately can I pinpoint a position. Without using DGPS or anything fancy. Can it be fractions of an inch? Can I check if a particular point is moving over years. Thanks, Angel Rodriguez Best regards, Angel mailto:angel@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: GPS position question Date: Thu, 22 Apr 1999 15:06:51 -0700 John and Larry -- I once tried averaging a GPS output over several days, and a 30 meter diameter circle was about as good as it got. There was also an error that occurred in about 0.1% of the position output readings that was up to 1000 meters and always along a NNE/SSW line. It occurred when the GPS changed from one satellite to another. There were a few nearby trees and power lines, but I don't know if that had any effect. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... At 12:59 PM 4/22/99 -0700, you wrote: >One would think that if the error were randomly scattered about the "real" >position that a long term average should approach a more accurate mean. But >the satellite tracks and such are not random as far as I know, and this might >introduce some systematic error into the average... If the systematic error >is simple in nature, then maybe it can be removed by relatively simple >statistical techniques. It would be interesting to plot all the data you get >into a "cloud" plot and see what it looks like. If it is elliptical, then >correction should not be too hard... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: GPS position question Date: Thu, 22 Apr 1999 16:21:41 -0600 (MDT) I would still think that averaging would end up giving a better result. Because of the system that is used to make the data less accurate, the errors can not be considered random, but they are limited in size. It might take many months, but the average should converge toward the true location eventually. JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: GeE777@....... Subject: Re: GPS position question Date: Thu, 22 Apr 1999 18:44:41 EDT In a message dated 4/22/99 3:21:38 PM Pacific Daylight Time, lahr@................... writes: > I would still think that averaging would end up giving a better > result. Because of the system that is used to make the data > less accurate, the errors can not be considered random, but they > are limited in size. > We get within a few feet when we place a GPS receiver at a known location and another for our surveys. (Exploration Seismic) The time is noted for each reading and we then see the error and direction of error at that time in the receiver at the known location, we then can back out the error from our unknown location data. George Erich Seismic Exploration Consultant P. O. Box 2011, Norwalk, CA 90651, U. S. A. Phone (562) 868-6013 e-mail GeE777@....... 33 53.90N 118 04.53W .. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Re: integrators Date: Thu, 22 Apr 1999 21:46:38 -0700 A stand-alone integrator with a resistor input, capacitor feedback and op amp will sooner or later saturate the amplifier output. Any amount of offset current over time equals a big number. So, stand alone integrators need a feedback resistor in parallel with the capacitor to make them work. However, this is not the only way to keep things settled down. If you have a more complex circuit that takes some of the DC at the output of the op amp and loops it around through a devious path but ending up back at the input with the right polarity, this can also keep things on track. I suspect any circuit with a true integrator has some other current feedback for DC stability. Sometimes such circuits turn into oscillators. -- Doug Crice web site http://www.georadar.com GeoRadar Inc. e-mail dcrice@............ 19623 Via Escuela Drive phone 408-867-3792 Saratoga, CA 95070 USA fax 408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Re: integrators Date: Fri, 23 Apr 1999 11:50:11 -0400 Doug, In the STM-8, it's the main feedback loop that establishes the DC operating point. The main loop adjusts the mass position ever so slightly, sufficient to compensate for small leakage currents in the integrator. The whole subject of how feedback circuits respond to errors inserted at random places in the loop is worth looking at. Maybe sometime I can put some of that in the feedback discussion on my Web page. Brett At 09:46 PM 4/22/99 -0700, you wrote: >A stand-alone integrator with a resistor input, capacitor feedback and >op amp will sooner or later saturate the amplifier output. >I suspect any circuit with a true integrator has some other current >feedback for DC stability. Sometimes such circuits turn into >oscillators. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Wayne Abraham J73WA Subject: Re: GPS position question Date: Fri, 23 Apr 1999 12:21:50 -0400 Angel If 25 meters or so is as accurate as the GPS will get with averaging over a few weeks, how can volcanologists know when a volcano is inflating or deflating a few centimeters using GPS? Wayne angel rodriguez wrote: > Hi John, > > I was asking the same questions a while back and while almost every > one agreed that about 25 meters was the best one could do here is the > best of the answers I got. > > From: "Peter H. Dana" > To: "'Angel Rodriguez'" > Subject: RE: Question > Date: Sat, 20 Feb 1999 17:32:33 -0600 > > Angel: > Thank you for your interest in the Geographer's Craft GPS Overview. > Not really goofy - you can certainly do that - and long term averaging > will reduce those GPS errors that average to zero - but the trouble is the > two biggest errors don't average to zero - often even after many weeks. > Selective Availability and the ionospheric errors are biases that change > all the time. So an average taken over one week might well differ by > several meters from an average taken over another week. > But - this is not the real problem - you might even find that for four > weeks in a row you got the same value, there is no guarantee that the fifth > week or even the second month will be the same. Usually agreement to ten > meters is possible from week to week - but rarely better than that. > You also have no way to evaluate the answer - > So tectonic drift is done using networks of carrier phase receivers that > use L1- and L2 to measure the ionosphere and special precise ephemeris sets > rather than broadcast orbital data. > > Peter > > Peter H. Dana - Department of Geography - University of Texas at Austin > Austin, Texas 78712-1098 - Tel: (512) 869-1450 - Fax: (512) 869-0899 > > -----Original Message----- > From: Angel Rodriguez [SMTP:angelr@............. > Sent: Saturday, February 20, 1999 2:39 PM > To: pdana@............... > Subject: Question > > Hi, > > This may be a goofy question, but here goes. > > If I read the output from my cheap gps receiver into a computer and average > the reading over weeks and months, just how accurately can I pinpoint a > position. Without using DGPS or anything fancy. > > Can it be fractions of an inch? Can I check if a particular point is moving > over years. > > Thanks, > > Angel Rodriguez > > Best regards, > Angel mailto:angel@............ > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Wayne Abraham 1430 Rodney Street Portsmouth, Dominica abrahamw@........ http://www.freeyellow.com/members6/dominicapsn/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: angel rodriguez Subject: Re[2]: GPS position question Date: Fri, 23 Apr 1999 11:57:51 -0500 Hello Wayne, Friday, April 23, 1999, 11:21:50 AM, you wrote: WAJ> Angel WAJ> If 25 meters or so is as accurate as the GPS will get with averaging over a few WAJ> weeks, how can volcanologists know when a volcano is inflating or deflating a few WAJ> centimeters using GPS? WAJ> Wayne So tectonic drift is done using networks of carrier phase receivers that use L1- and L2 to measure the ionosphere and special precise ephemeris sets rather than broadcast orbital data. I have a friend in Newport (near LA) that took a lab for geology class and it included a be of this and I guess what they do is have points marked all over the place and visit the places regularly and take a reading at that point and then go back to the lab and do post processing and that done over time gives very accurate results. The point are nails driven in parking lots and sidewalks and most anyplace from what she told me. There is some usefull software that you can hookup you gps to and it will make nice graphs and dot maps of the point read over any time period. You can internet DGPS and get more accurate see http://www.sni.net/kawin/ and check out http://joe.mehaffey.com for a good faq regards, angel _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "ALBERT HRUBETZ" Subject: WIND NOISE Date: Fri, 23 Apr 1999 12:35:25 -0500 An experimental project regarding wind noise was conducted by the geophysical research department of a major oil company in the early 50's. This was the era when magnetic tape recording was just being introduced to seismic data collection. While the research department was enthusiastically experimenting with magnetic tape, both in the laboratory and in the field, the reflection seismograph production crews still recorded data on film or paper. One of the obvious benefits of magnetic tape recording was the ability to stack, or composite individual seismic traces, yielding significant advances in improvement of signal/noise ratio. The subject experiment dealt with the question of whether wind noise, acting as an energy source agent, could produce seismic reflection events of recognizable magnitude. It was recognized that the energy would be miniscule, and that long recording periods would be required to determine if this were possible. Could the combination of long recording times plus signal compositing bring forth reflection events? To determine the answer, a standard production-type recording profile was utilized, the same as that used with a dynamite energy source. The layout was at the company's northern Oklahoma test site, where previous reflection events had been identified with the various subsurface layers of strata. The recording unit was left running for extended periods of time throughout the day. The data were then taken to their data processing center, and the traces electronically stacked to various degrees. The result was that seismic reflection events could be identified with various geological strata to a depth of approximately 5000'! I believe that was about the thickness of the sedimentary section at this location. I remember reading the research report with awe. The conclusion, as I recall, was that the agitation of grass and roots caused by the wind generated minute energy sources. The random energy was cancelled out by signal compositing, while the coherent energy, ie., reflections from subsurface acoustic impedance interfaces, was sufficiently enhanced by long recording time and multiple compositing to yield visible reflection events. The reflections were weak, not nearly as strong as that produced by the comparable dynamite record, but nevertheless they were there! The economic use of such a layout would be to set up the recording geophone spread at various locations, and then spot correlate the reflection events to give a subsurface map of the area. I can quickly think of several reasons why this was not used in oil-finding. One, spot correlation is generally used only to locate large structural features favorable for oil accumulation. In most of the U. S. sedimentary basins, the large features already were found and a continuous correlation process had to be used to locate the smaller structures. Secondly, the time and effort required to obtain a record - one full day - just wasn't worth it. Nevertheless, I consided it a noble experiment, even though geophyscial operations wasn't much interested except as a scientific curiousity. Albert Hrubetz _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ted Blank Subject: Re: GPS position question Date: Fri, 23 Apr 1999 10:52:14 -0700 (PDT) Differential GPS uses a GPS receiver on earth at a known location. Since it knows where it is, it broadcasts correction information which can be used to back out the built-in errors associated with Selective Availability etc. DGPS corrections are not broadcast on GPS channels but on some other freq. Boaters use it all the time. Ted Blank San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: David Josephson Subject: Re: GPS position question Date: Fri, 23 Apr 1999 11:05:43 -0700 (PDT) Ted Blank writes > Differential GPS uses a GPS receiver on earth at a known location. > Since it knows where it is, it broadcasts correction information which > can be used to back out the built-in errors associated with Selective > Availability etc. DGPS corrections are not broadcast on GPS channels but > on some other freq. Boaters use it all the time. Another poster mentioned using two receivers, one fixed and one roving, to do homebrew. There is one caveat for anyone trying DGPS: both the reference and the moving receivers must be using the same set of satellites at any given instant, or the DGPS data won't be very good. Just taking two receivers and differencing the outputs doesn't work (unless you're lucky and they happen to choose the same set of satellites for the solution). I'm not sure how the currently implemented DGPS broadcast corrections take care of this; it's either by broadcasting corrections per satellite, or by specifying which satellites to use in the solution. -- David Josephson / Josephson Engineering / San Jose CA / david@............. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: GPS position question Date: Fri, 23 Apr 1999 15:57:03 -0700 The DGPS methods I'm familiar with broadcast correction information for each satellite. A special GPS receiver is positioned at a known location and the signal from each satellite in view is compared against what it should have been given the satellite ephemeris and the receiver's known location. That information is broadcast via the DGPS transmitter. This way, the user's GPS receiver is free to use any satellite. Commercially available DGPS via subscription is broadcast on a subcarrier of selected commercial FM radio stations. These signals are often encrypted. The Coast Guard broadcasts publically available DGPS via transmitters in the 200kHz to 450kHz band, and are available to anyone that wants to receive and decode the signals. The modulation and signal encoding specification is available on the Internet, but I don't remember where. Search for RTCM SC-104. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... At 11:05 AM 4/23/99 -0700, you wrote: >Another poster mentioned using two receivers, one fixed and one roving, >to do homebrew. There is one caveat for anyone trying DGPS: both the >reference and the moving receivers must be using the same set of satellites >at any given instant, or the DGPS data won't be very good. Just taking two >receivers and differencing the outputs doesn't work (unless you're lucky >and they happen to choose the same set of satellites for the solution). I'm >not sure how the currently implemented DGPS broadcast corrections take care >of this; it's either by broadcasting corrections per satellite, or by >specifying which satellites to use in the solution. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: browning Subject: odd low frequency vibrations Date: Fri, 23 Apr 1999 19:20:46 -0400 All, Over the last week many people here on Hatteras Island, NC, have been aware of a low frequency rumble that we feel as pressure on our ears as much as hear. It comes and goes during most of the day and night, although I feel it more at night. I'm picking this signature up with a mark-4 geophone into sdr. The background here is generally about +-30 and truck noise usually doesn't trigger. It appears to be a sine wave of about 10 hz modulated with a period of about 1.75 seconds. There are several bombing ranges located from 25 to 50 miles from us but none use live ordinance (only 12 ga smoke shells). The sand here is about 10,000 feet think with stratified mud layers dispersed throughout, which create quiet a bit of ducting of landslide noise from the continental shelf. There is a bridge being constructed about 40 miles away with driven piles. Please download the file and expand the x axis to see what it looks like. I'm open to all theories. http://home.interpath.net/llb/990422d.hat http://home.interpath.net/llb/sample.JPG Thanks, Lou Browning _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: SW6079@....... Subject: Re: odd low frequency vibrations Date: Sat, 24 Apr 1999 00:13:59 EDT Reminds me of the "Taos Hum" heard widely (or more likely, felt) a few years ago. I think there was even a web page devoted to it. Whether they ever solved it, I don't know. Good Luck. Mike. sw6079@....... N7ORL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Dick Webb Subject: Re: odd low frequency vibrations Date: Sat, 24 Apr 1999 07:41:32 -0400 Lou, I happen to live in Raleigh and from time to time see a similar very low amplitude pattern. No sound or sensation. I always thought it was wind related. Unfortunately I don't have a trace but as i recall it went on for hours, even days and appeared to be the sum of two sine waves. I've also read in the newspaper that people on the coast have had similar experiences in the past. It's good to know that there is a PSN type so close. There ain't to many of us in the southeast. Dick At 07:20 PM 4/23/99 -0400, you wrote: >All, > Over the last week many people here on Hatteras >Island, NC, have been aware of a low frequency >rumble that we feel as pressure on our ears as much >as hear. It comes and goes during most of the day >and night, although I feel it more at night. I'm >picking this signature up with a mark-4 geophone >into sdr. The background here is generally about >+-30 and truck noise usually doesn't trigger. >It appears to be a sine wave of about 10 hz >modulated with a period of about 1.75 seconds. >There are several bombing ranges located from 25 to >50 miles from us but none use live ordinance (only >12 ga smoke shells). The sand here is about 10,000 >feet think with stratified mud layers dispersed >throughout, which create quiet a bit of ducting of >landslide noise from the continental shelf. There >is a bridge being constructed about 40 miles away >with driven piles. Please download the file and >expand the x axis to see what it looks like. I'm >open to all theories. > >http://home.interpath.net/llb/990422d.hat > >http://home.interpath.net/llb/sample.JPG > >Thanks, >Lou Browning > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: The Lahrs Subject: Re: odd low frequency vibrations Date: Sat, 24 Apr 1999 09:48:43 -0600 Lou, You have a very interesting recording there. It's great to have the information recorded rather than just people's description that they are hearing something, as the latter might be dismissed. Is the noise limited to Hatteras Island, NC? With a portable station it might be possible to locate the source of the noise, if the amplitude is fairly steady. Or a small array could be used to determine the direction of the source. Maybe Larry has some ideas on this, as he was recently studying a local pile- driving operation. JCLahr * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * AOL version of homepage: * * http://lahr.org/john-jan/homepage.html * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Stephen Caruso" Subject: Tornado info Date: Sat, 24 Apr 1999 12:31:38 -0400 I am leaving for a week but will reconnect. Thanks for the info on tornados. I have forwarded this info to our state geologist here. Stephen Caruso _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: browning Subject: Re: odd low frequency vibrations Date: Sat, 24 Apr 1999 14:05:59 -0400 John, I have had more anomalous signals here on Hatteras mixed in with more normal looking, ie. ragged edged plots, so I don't think this is an instrument malfunction. The plots from Hickory, NC seem to have the same amplitude modulated dual frequency appearance although I haven't examined the sdr files from other stations, only the screen captures. After looking around the web I am starting to explore LFAS (low frequency active sonar) as a possible source. I have had no luck in obtaining any spectrum analysis of the military systems because I think they're still classified not to mention being a pretty hot potato politically. Baltimore Canyon to Hatteras Canyon seem to be a favorite testing ground for the navy, being deep water and so close to Norfolk, VA. I am going to try to send the files to a friend who is a DOD sonar analysis software specialist for a look, when he gets back in the country, although he may not be able to say one way or another. To answer your question, I don't think that this signal is local to Hatteras but more to the mid-atlantic coast. I am going to try to build an infrasonic sensor to put on another channel to get a better idea of the spectrum. The navy left the island several years ago and demolished the base, but left (unknowingly) two strings of sosus sensors 70 miles long with 44 hydrophones each. I may have to see about getting access to the strings because I understand you could hear a whale belch all the way from the mid-atlanic ridge. Too many interests, too little time, Lou Lou _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: angel rodriguez Subject: Re: New WinQuake beta release and SDR release. Date: Sat, 24 Apr 1999 13:10:54 -0500 >Hi Angel, >Interesting event file. Do you know if the events are do to volcanic >activity? You should also send an email out to the PSN-L list about it.... >-Larry Hi Larry, I posted the event to the new events list it called 990422m.iz. The file covesr about 3.5 hours. These quakes are in Costa Rica close to the Panama border. While the Talamaca range, which has volcanos is in this area I don´t know if the events are volcanic. I get lots of events from that area but I haven´t seen a swarm like this. I would appreciate any and all comments. regards, angel _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: angel rodriguez Subject: 2 correction to my last message Date: Sat, 24 Apr 1999 14:37:05 -0500 Hi, Sorry about the misleading subject line, you can guess how that happend. :) The name of the event on the New Events List is 990422a.iz not 990422m.iz like I wrote. Angel _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Wayne Abraham J73WA Subject: Re: New WinQuake beta release and SDR release. Date: Sat, 24 Apr 1999 17:47:16 -0400 Angel Your events look like a swarm of volcanic quakes similar to those we've b= een having here in Dominica. Do you have a volcano between 82 and 87 miles fr= om your station? Wayne angel rodriguez wrote: > >Hi Angel, > > >Interesting event file. Do you know if the events are do to volcanic > >activity? You should also send an email out to the PSN-L list about it= ..... > > >-Larry > > Hi Larry, > > I posted the event to the new events list it called 990422m.iz. The fi= le > covesr about 3.5 hours. These quakes are in Costa Rica close to the > Panama border. While the Talamaca range, which has volcanos is in > this area I don=B4t know if the events are volcanic. I get lots of > events from that area but I haven=B4t seen a swarm like this. > > I would appreciate any and all comments. > > regards, > > angel > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Wayne Abraham 1430 Rodney Street Portsmouth, Dominica abrahamw@........ http://www.freeyellow.com/members6/dominicapsn/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rex Klopfenstein, Jr." Subject: Model-to-VBB Questions Date: Sat, 24 Apr 1999 18:30:31 -0400 Sean I have been looking at your drawings in some detail and trying to calculate the RP, RI, TI(R), and TI(C). I have several questions. First, does what you call "effective period" in your EDSEIS schematic refer to the Tn variable in your model equations? If that is true, I used the effective period equation in your model to calculate the TI valves. I substituted in the RI and RP values listed on your schematic. I also used all values listed on your Mathcad model. I came up with the TI values of 1s, 10s, 20s, 40s, 40s, 40s for Tn values of 1s, 20s, 40s, 80s, 160s, 320s respectively. Is this right? Now using the damping equation from your model and the above TI values, I calculated the damping factor for each Tn. Again I use the values listed in your model except r which I believe you have changed to 2,000,000 and Rp and RI values listed on your schematic. I get damping factors that range from 0.610 to 0.774. I think I will take your advice and include a two position switch for my version. One which sets Tn to 1 sec for adjustment and the other for the actual detector parameters. I will however show the six position switch on my schematic. Thanks in advance -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: angel rodriguez Subject: swarms Date: Sat, 24 Apr 1999 17:31:14 -0500 Hello Wayne, I don´t know. There are some quite active volcanos at about 500 km and 350 km, a dead one at about 12 km but I'll have to check to see if there is anything around that distance, but I really don't think so. regards, angel _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: New sensors on line. Date: Sat, 24 Apr 1999 15:33:50 -0700 All, I have three new sensors online. Some background; A few months ago Aaron Barzilai, a grad student a Stanford Univ. contacted me about a new sensor he is working on. He is working on converting a standard geophone, he is using a Geospace GS-11D, to a broadband device. Aaron has information about his new sensor at http://micromachine.stanford.edu/smssl/Geophones/GeophoneResearch.html. He asked me if I could record some data using his sensor, and, a standard GS-11D and a Guralp broadband sensor, a CMG-40T (30sec to 50hz velocity sensor) on loan from the PASCAL program as references. SURE I said.... Last Sunday (4/18) Aaron came by and we installed all of his sensors. I made up another 16 bit SDR system, with GPS timing, to record the new sensors. The sensors are placed in the same spare bedroom with my other sensor. The new sensors have the following event files names: *.ABG This is the un modified GS-11D short period (4.5hz) vertical sensor. *.ABX This is Aaron's experimental BB sensor. Output is acceleration. *.GUZ The Z channel of the Guralp. *.GUN The N/S channel of the Guralp. *.GUE The E/W channel of the Guralp. All of the channels go through one of my Amp / Filter boards with a 20 hz 7 pole low-pass filter and a 1 pole 60 sec. high-pass filter. So now we wait for some events..... BTW: Aaron is on the PSN-L list, so if you have any comments about his sensor you can send it to the PSN-L list and he should see it. -Larry Cochrane 24 Garden St. Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: pouellette Subject: Re: odd low frequency vibrations Date: Tue, 23 Mar 1999 11:37:37 -0500 For some info on monitoring infrasonic waves see http://www.tiac.net/users/shansen/belljar/microbar.htm . Some useful info there. Peter browning wrote: > John, > I have had more anomalous signals here on > Hatteras mixed in with more normal looking, ie. > ragged edged plots, so I don't think this is an > instrument malfunction. The plots from Hickory, NC > seem to have the same amplitude modulated dual > frequency appearance although I haven't examined the > sdr files from other stations, only the screen > captures. After looking around the web I am > starting to explore LFAS (low frequency active > sonar) as a possible source. I have had no luck in > obtaining any spectrum analysis of the military > systems because I think they're still classified not > to mention being a pretty hot potato politically. > Baltimore Canyon to Hatteras Canyon seem to be a > favorite testing ground for the navy, being deep > water and so close to Norfolk, VA. I am going to > try to send the files to a friend who is a DOD sonar > analysis software specialist for a look, when he > gets back in the country, although he may not be > able to say one way or another. > To answer your question, I don't think that this > signal is local to Hatteras but more to the > mid-atlantic coast. > I am going to try to build an infrasonic sensor > to put on another channel to get a better idea of > the spectrum. The navy left the island several > years ago and demolished the base, but left > (unknowingly) two strings of sosus sensors 70 miles > long with 44 hydrophones each. I may have to see > about getting access to the strings because I > understand you could hear a whale belch all the way > from the mid-atlanic ridge. > > Too many interests, too little time, > Lou > > Lou > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: aaron barzilai Subject: Re: New sensors on line. Date: Sat, 24 Apr 1999 18:07:59 -0700 (PDT) > So now we wait for some events..... BTW: Aaron is on the PSN-L list, so if > you have any comments about his sensor you can send it to the PSN-L list > and he should see it. Indeed I do see it. I'll be at SSA with a poster a week from Tuesday, so if you're there, please stop by. I'm hoping I'll get some good data at Larry's, but I'm sure with some advice from the list I can improve my sensors even more. Thanks, Aaron _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Re: New sensors on line. Date: Sat, 24 Apr 1999 21:47:59 -0700 aaron barzilai wrote: > Indeed I do see it. I'll be at SSA with a poster a week from Tuesday, so if I remember seeing your web page a long time ago. I just downloaded one of the slide shows and it explains quite a bit. If it works well in use, are there any production plans? some way to get the things pre-made or a kit? I have a 4.5 Hz GS-11D here. Thanks for what you're working on, Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: aaron barzilai Subject: Re: New sensors on line. Date: Sun, 25 Apr 1999 09:40:00 -0700 (PDT) > > If it works well in use, are there any production plans? some way to get > the things pre-made or a kit? > > I have a 4.5 Hz GS-11D here. > Well, I don't intend to start a company after I graduate if that's what you mean. I have a vague notion that I might be able to crank a few out and distribute them in the mid to long term range. Aaron _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Re: New sensors on line. Date: Sun, 25 Apr 1999 09:46:26 -0700 aaron barzilai wrote: > Well, I don't intend to start a company after I graduate if that's > what you mean. I have a vague notion that I might be able to crank a > few out and distribute them in the mid to long term range. I figured Oyo, Guralp or Mark Products might want to buy it off of you. It would probably pay off those pesky student loans. ;) ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: VBB from 4.5hz phone Date: Sun, 25 Apr 1999 14:18:30 -0500 (CDT) Aaron, I saw your preliminary poster at the IRIS workshop in Santa Cruze last June; it was near where I had the poster on the educational seis. I was unable to catch you there, and I hoped to see you at the AGU in SFO in December but didn't manage to get any funds to attend it. (I submitted an abstract but I was unable to find someone to post my poster on the calibration of the educational VBB seis). I have been experimenting for several years with making almost any seismometer into a VBB sensor if the physical parameters are suitable, like the coil resistance. THe largest is a WWNSS LP (15 second T0 and 11 kg mass) vertical that I am running at 600 seconds. As you may have gathered, the small geophones have been an attraction. I have been experimenting for about two years with making the 4.5 hz HS-1 (by Geospace, but similar to the GSC-11d and the Mark Products L-15B) into a broadband instrument. I use the VRDT displacement sensor mounted externally above the case, with the sensing vane attached to the upper mass ring. With VBB parameters set for 20 seconds and the proper coil resistance, the VBB output is 750 volts/meter/second and the calibrations fit the transfer functions. But the data is to noisy for a sensitive broadband sensor, and I am usually barely able to see the normal 6-second microseism background of 1 to 2 microns/second. Of course these were very clear (~10x) when hurricane Bonnie passed last August. I also made a nice record (from St. Louis) of the Ohio quake in September, with peak velocities of Lg of about 10 microns/second at about 8 seconds. The trouble with the 4.5hz phone is that the mass is only 23 grams, and the intrinsic damping of 0.28 means that the Q is not very high. From the Riedesel paper this would be expected to have a Brownian noise power spectral density (PSD) level of about -165db (figure 12). (For reference, the USGS low noise model has the 6-second microseism peak at about -140db, the 12-second peak at -160db, and the quiet earth minimum between 40 and 200 seconds is about -185 db.) But the Brownian noise is only one of many noise sources; the circular suspension leaf springs and the fine-wire signal output leads are significant contributors. The Reidesel paper finds that when using the velocity signal coil and a properly selected amplifier, the noise level is -130db at 1 hz, and the 6-second microseisms cannot be seen. We can do much better with a VBB fedback configuration. The PSD of several noise samples was about -145db at 6 seconds, but levels off at about -155db at 10 seconds. It has trouble recording teleseisms compared with a larger VBB seis, like a Mb5.O west of Mexico or a 6.2 in China, where the 20-second surface waves were only about 2X the noise. It did make a reasonable record of a Ms 6.0 in the Queen Charlotte Islands (51N,130W). It may be possible to reduce the suspension noise, and I have a new geophone to modify with great care to try to minimize it. Other problems are with the thermal sensitivity of the mass position and suspension resonances within the high-frequency portion of the VBB passband. THe manufacturers are mum on these; the most notorious are the resonances of the 1-hz L4-C at 16 and 22 hz. The mass position change with temperature is a "don't care" for a velocity sensor, but it causes problems with a displacement output of 250 millivolts/micron, even with reasonable VBB loop gains. I have lately been working with a larger 2 hz geophone to avoid some of these problems. I am hoping to get a noise level of -170db, which is below the USGS low noise model out to 20 seconds. It still won't be as quiet as a larger, longer mechanical period VBB sensor. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: GS -D11 GEOSPACE Date: Sun, 25 Apr 1999 21:47:54 +0200 The problem is this:=20 our network would like to buy some Geospace GS-11D 4.5 Hz. I have more = times asked information via mail to the Geospace for where to find in = Italy such geophones, but unfortunately I have never received an answer. = =20 Someone can find them and sell them to us, used also? Thanks for the help. Francesco Nucera - Italian Experimental Seismic Network PSN Italy
The problem is this:
our network would like to buy some  Geospace GS-11D 4.5 Hz. I = have=20 more times asked information via mail to the Geospace for = where to=20 find in Italy such geophones, but unfortunately I have never received an = answer. 
Someone can find them and sell them to us, used = also?
 
Thanks for the help.
 
Francesco Nucera     -    = Italian=20 Experimental Seismic Network PSN Italy
From: S-T Morrissey Subject: VBB parameters Date: Sun, 25 Apr 1999 15:15:05 -0500 (CDT) Rex, Yes, Tn is the effective period of the feedback; To is the mechanical period of the spring-mass sensor (here it is 8 seconds). Naturally, there are some corrections to the schematic you have. There is a 2meg resistor missing at position 3 of the 4th pole of the switch at the Brn lead, and the RI for the 5th position of the 2nd pole should be 405k ohms, not 810.57k. The integrator periods should work out to 1,10,20,40,80, and 80 seconds. Here is how the values are calculated: (see your Mathcad worksheet) Preset Cp = 20uf, listed as farads (20 * 10^-6) M = the mass, Kg r = 1 000 000 volts/meter/second (I used this value) zeta = the damping = 1/2*sqrt(2) = 0.7071 Wo = the angular mechanical frequency of the seis = 2*pi/To Gn = the force coil constant , Newtons/Ampere Then with: G = Gn/M Calculate the output: k = 1/(G*C) (volts/meter/second) (this is the level of the flat portion of the response for all periods) Select: TI (a convenient integrator period based on capacitor selection) and Tn (the effective broadband period you want) Solve the TI expression for RI: (you can edit the Mathcad) RI = 1/(Cp*TI)*[Tn/(2*pi)]^2 Solve the damping expression for Rp: Rp = [2*zeta*sqrt(Cp/(TI*RI))-Wo^2/(r*G)]^-1 If my ASCII-algebra is correct, you should get the values listed. You also have the quad-amplifier schematic: change the capacitors around A1 to 0.001uf; otherwise Td is much too long and the seis oscillates. Following the recent integrator discussions, note that the integrator works just fine as drawn, as a 1-pole low-pass non-inverting filter. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: aaron barzilai Subject: Re: VBB from 4.5hz phone Date: Sun, 25 Apr 1999 13:51:16 -0700 (PDT) Sean (and everyone), It's going to take me a couple of days to carefully read, digest and respond to your comments. Sean, I must say from being on the list, it's quite impressive how much you contribute. I appreciate the time you took to think about and discuss my research. I'm looking forward to talking about it with you in the future. Will you be at SSA? Aaron _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Re: GS -D11 GEOSPACE Date: Sun, 25 Apr 1999 14:07:39 -0700 Franciesco, I buy geophones from Geo Space regularly in small quanitites. There is not reason you should nor receive a prompt answer from them. Check the address: Geo Space Corporation 7334 N. Gessner Road Houston, TX 77040 phone 713-939-7093 fax 713-937-8012 They should either accept your order or refer you to their agent in Italy. Probably fax is the best way to contact them. I suggest you address it to Tim Almandinger. If you don't get an answer, let me know and I will reprimand him severely. If nothing else works, I can buy some and export them to you. -- Doug Crice web site http://www.georadar.com GeoRadar Inc. e-mail dcrice@............ 19623 Via Escuela Drive phone 408-867-3792 Saratoga, CA 95070 USA fax 408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: R: GS -D11 GEOSPACE Date: Mon, 26 Apr 1999 00:03:18 +0200 Thank you Doug, I will try tomorrow to send a fax.=20 Francesco =FF=FE<=00!=00D=00O=00C=00T=00Y=00P=00E=00 =00H=00T=00M=00L=00 = =00P=00U=00B=00L=00I=00C=00 = =00"=00-=00/=00/=00W=003=00C=00/=00/=00D=00T=00D=00 =00H=00T=00M=00L=00 = =004=00.=000=00 = =00T=00r=00a=00n=00s=00i=00t=00i=00o=00n=00a=00l=00/=00/=00E=00N=00"=00>=00= =0D=00=0A= =00<=00H=00T=00M=00L=00>=00<=00H=00E=00A=00D=00>=00=0D=00=0A= =00<=00M=00E=00T=00A=00 = =00c=00o=00n=00t=00e=00n=00t=00=3D=00"=00t=00e=00x=00t=00/=00h=00t=00m=00= l=00;=00 = =00c=00h=00a=00r=00s=00e=00t=00=3D=00u=00n=00i=00c=00o=00d=00e=00"=00 = =00h=00t=00t=00p=00-=00e=00q=00u=00i=00v=00=3D=00C=00o=00n=00t=00e=00n=00= t=00-=00T=00y=00p=00e=00>=00=0D=00=0A= =00<=00M=00E=00T=00A=00 = =00c=00o=00n=00t=00e=00n=00t=00=3D=00"=00M=00S=00H=00T=00M=00L=00 = =005=00.=000=000=00.=002=000=001=004=00.=002=001=000=00"=00 = =00n=00a=00m=00e=00=3D=00G=00E=00N=00E=00R=00A=00T=00O=00R=00>=00=0D=00=0A= =00<=00S=00T=00Y=00L=00E=00>=00<=00/=00S=00T=00Y=00L=00E=00>=00=0D=00=0A= =00<=00/=00H=00E=00A=00D=00>=00=0D=00=0A= =00<=00B=00O=00D=00Y=00 = =00b=00g=00C=00o=00l=00o=00r=00=3D=00#=00f=00f=00f=00f=00f=00f=00>=00=0D=00=0A= =00<=00D=00I=00V=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=002=00>=00T=00h=00a=00n=00k=00 =00y=00o=00u=00 = =00D=00o=00u=00g=00,=00 =00I=00 =00w=00i=00l=00l=00 =00t=00r=00y=00 = =00t=00o=00m=00o=00r=00r=00o=00w=00 =00t=00o=00 =00s=00e=00n=00d=00 = =00a=00 =00f=00a=00x=00.=00 =00=0D=00=0A= =00<=00/=00F=00O=00N=00T=00>=00<=00/=00D=00I=00V=00>=00=0D=00=0A= =00<=00D=00I=00V=00>=00&=00n=00b=00s=00p=00;=00<=00/=00D=00I=00V=00>=00=0D= =00=0A= =00<=00D=00I=00V=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=002=00>=00F=00r=00a=00n=00c=00e=00s=00c=00o=00<=00= /=00F=00O=00N=00T=00>=00<=00/=00D=00I=00V=00>=00<=00/=00B=00O=00D=00Y=00>= =00<=00/=00H=00T=00M=00L=00>=00=0D=00=0A= =00 From: GeE777@....... Subject: Re: GS -D11 GEOSPACE Date: Sun, 25 Apr 1999 19:21:23 EDT In a message dated 4/25/99 12:48:26 PM Pacific Daylight Time, franuc@...... writes: > Someone can find them and sell them to us, used also? Contact Geospace e-mail geospace@................ Also try R. T. Clark who deals with used geophysical equipment e-mail rtclark@........... Clark did not have any 4.5 HZ GSC 11D in their winter catalog. George Erich Seismic Exploration Consultant P. O. Box 2011, Norwalk, CA 90651, U. S. A. Phone (562) 868-6013 e-mail GeE777@....... 33 53.90N 118 04.53W _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: aheerfor@...... Subject: Re: odd low frequency vibrations Date: Mon, 26 Apr 1999 12:21:30 +0200 > All, Over the last week many people here on Hatteras Island, NC, have been aware of a low frequency rumble that we feel as pressure on our ears as much as hear. It comes and goes during most of the day and night, although I feel it more at night. I'm < I have been picking up similar signals for some months in Denmark. The source is still a mystery, but a theory which matches the measurements quite well is secret underground tunnelling. I could say a lot more about that. Regards, Anders _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: angel rodriguez Subject: Re: GS -D11 GEOSPACE Date: Mon, 26 Apr 1999 08:33:27 -0500 Hello Francesco, Sunday, April 25, 1999, 2:47:54 PM, you wrote: F> The problem is this: F> our network would like to buy some Geospace GS-11D 4.5 Hz. I have more times asked information via mail to the Geospace for where to find in Italy such geophones, but unfortunately I have never F> received an answer. F> Someone can find them and sell them to us, used also? F> Thanks for the help. F> Francesco Nucera - Italian Experimental Seismic Network PSN Italy I think you might be able to get some used vericle 4.5 hz from Mitchum Industries. Jim Croix has been very helpfull in getting me some stuff. jim@..................... Best regards, Angel mailto:angel@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ted Blank Subject: Amateur builders and Schematics in magazines Date: Mon, 26 Apr 1999 09:04:54 -0700 (PDT) Those of us who can barely follow a recipe sometimes try to build electronic devices from magazine schematics (like Amateur Scientist). However most of the diagrams I've seen have at least one error which is described apologetically several months later. At least now you know why that darn thing never worked. Last month Sci Am published a design for an IR detector for monitoring cloud cover even at night. I thought I'd wait before building any of the electronic stuff. Sure enough, the Soc. for Amateur Scientists web page has a correction to the amplifier schematic published in the APril issue. I think people with EE backgrounds tend to underestimate the number of things one can do wrong while building a circuit. Like programming, unless all the parts work correctly the circuit won't work. However, the debugging environment for software is now very sophisticated and user-friendly, with interactive editors, breakpoints, etc. The average joe who builds a circuit from a magazine isn't going to have a scope or know how to debug someone elses mistake. I guess I'm asking this group (of probably some of the best hands-on designers and builders of amateur science devices in the world) - why is it so difficult to publish a diagram without errors and how can it be made more likely to succeed when somebody tries to build something even from a perfect schematic? The nice breadboard devices do help keep you organized but it's still like walking a tightrope. I know there's no perfect answer, but this has been on my mind for a long time and I thought I'd just invite comments. Ted Blank San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Kevin J. Rowett" Subject: Re: Amateur builders and Schematics in magazines Date: Mon, 26 Apr 1999 09:35:04 -0700 > >I guess I'm asking this group (of probably some of the best hands-on >designers and builders of amateur science devices in the world) - why is >it so difficult to publish a diagram without errors and how can it be >made more likely to succeed when somebody tries to build something even >from a perfect schematic? The nice breadboard devices do help keep you >organized but it's still like walking a tightrope. Few, if any magazine schematics get published from actual schematic CAD databases. Almost all of them are re-drawn by the magazines graphic department. The folks that draw the schematics don't have a lot of training in Electronics. So, one source of error is transcription. A corollary to this is the hack job some magazine editors do on an article. It's enlightening to read the article as submitted by the author, and compare it to what gets published. Few editors are practicing EEs. Circuit Cellar INK is one of the few that can claim they are. For breadboard ckts, I usually don't build them from a schematic. The final schematic gets done by reverse engineering the working breadboard. That can result in another kind of transcription errors. Sometimes (often!), good design practices and analysis do not get done for published ckts. To produce a ckt that will operate under the full range of tolerances encountered in the real world (part tolerances, voltage, temp, and frequency variances) requires more work than people sometimes want to put into a magazine article. Getting a working breadboard or schematic is a small percentage of the work needed to get a design into production. Lastly, just as in the professional world, not all engineers have equal skill. KR _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: New Madrid Fault Zone Article Date: Mon, 26 Apr 1999 11:13:12 -0700 (MST) Below is an article from Friday's "Science" issue that claims a lower seismic hazard for the New Madrid Seismic zone based on an empirical "frequency-magnitude" relation (also called the Gutenberg-Richter Law) and measurements that show little or no motion in the surrounding areas. I thi= nk their model is grossly oversimplified, but it is still interesting to read over... Also, the frequency-magnitude relation parameters change over time and do not usually work for quakes much larger than 5.0 (these fit the mode= l the worst, the best fit is mostly between 3.0 and 5.0). _________________________________________________________________ =20 Slow Deformation and Lower Seismic Hazard at the New Madrid Seismic Zone Andrew Newman, 1 Seth Stein, 1* John Weber, 2 Joseph Engeln, 3 Ailin Mao, 4 Timothy Dixon 4=20 =20 Global Positioning System (GPS) measurements across the New Madrid seismic zone (NMSZ) in the central United States show little, if any, motion. These data are consistent with platewide continuous GPS data away from the NMSZ, which show no motion within uncertainties. Both these data and the frequency-magnitude relation for seismicity imply that had the largest shocks in the series of earthquakes that occurred in 1811 and 1812 been magnitude 8, their recurrence interval should well exceed 2500 years, longer than has been assumed. Alternatively, the largest 1811 and 1812 earthquakes and those in the paleoseismic record may have been much smaller than typically assumed. Hence, the hazard posed by great earthquakes in the NMSZ appears to be overestimated. =20 1 Department of Geological Sciences, Northwestern University, Evanston, IL, 60208, USA. 2 Department of Geology, Grand Valley State University, Allendale, MI 49401, USA. 3 Department of Geological Sciences, University of Missouri, Columbia, MO 65211, USA. 4 Rosenstiel School for Marine and Atmospheric Sciences, University of Miami, Miami, FL 33149, USA. * To whom correspondence should be addressed. E-mail: seth@............. =20 _____________________ =20 During the years 1811 and 1812 a long sequence of earthquakes (1), including three large shocks thought to have had surface wave magnitudes near or exceeding 8 (2), was centered near New Madrid, Missouri. The region remains active, with small to moderate (magnitude less than 5) earthquakes concentrated along planar segments (Fig. 1) presumed to reflect subsurface faults (3). The few available focal mechanisms suggest that right-lateral strike-slip occurs on two NE-SW-striking, subvertical faults, whereas thrusting occurs on a shallowly SW-dipping fault that forms part of the left step between the strike-slip faults (4). The seismicity may reflect reactivation of Paleozoic faults (5) by platewide or local stresses (6). _________________________________________________________________ =20 [LINK] Fig. 1. Residual horizontal site velocities (1997 to 1991) for the New Madrid GPS network, after removal of the motion of the North American plate. Velocities are small, within 2 sigma error ellipses. [View Larger Version of this Image (36K GIF file)] _________________________________________________________________ =20 We use local and platewide GPS data to assess the deformation and draw inferences about the recurrence of large earthquakes. In the local study, we monitor a network of geodetic monuments including sites near the seismicity, in unconsolidated alluvium and semiconsolidated bedrock of the Mississippi embayment, and in bedrock outside the embayment (7). The network was surveyed in November 1991, October 1993, and October 1997 (8). Horizontal velocities obtained from least-squares fits to the site positions (9) are shown in Fig. 1, after removal of the motion of the North America plate (10). Almost all residual velocities are small and within the 2 sigma error ellipses estimated from the repeatability of daily site positions, scaled to include the effects of time-correlated errors (11). =20 We examined the data using a geometry in which the motion expected between large earthquakes should be evident, assuming strain accumulation on a locked right-lateral strike-slip fault. Site motions were projected along N42=B0E, the approximate strike of the strike-slip faults. We then removed the mean and compared the data with the predicted velocity profile for a locked vertical strike-slip fault, a steep gradient near the fault that asymptotically approaches the far-field interseismic rate away from the fault (Fig. 2) (12). The assumed locking depth affects only the shape of the steep central part of the profile. We used a locking depth of 25 km and considered rates between 6 and - 6 mm/year (negative rates denote left-lateral motion) to find misfit as a function of rate. To estimate uncertainties in the best fitting rate, we rescaled the misfit to have reduced chi 2 =3D 1 at the minimum and used a chi 2 test to find 95% (2 sigma ) confidence limits. _________________________________________________________________ =20 [LINK] Fig. 2. (Top) Profile of site velocities with 1 sigma error bars, parallel to the approximate strike of the major strike-slip faults in the NMSZ. Solid and open symbols denote near- and intermediate- field sites. Mean velocity is removed. Also shown is a best-fitting model profile for a locked vertical strike-slip fault driven by interseismic motion. (Bottom) Misfit as a function of interseismic rate is shown with 2 sigma ranges shaded. None of the best-fitting rates differs significantly from zero. [View Larger Version of this Image (41K GIF file)] _________________________________________________________________ =20 Using all sites yields a best fitting rate of - 0.2 =B1 2.4 mm/year. Dividing these into near-field (within the embayment) and intermediate-field (primarily hard rock) sites yields 0.6 =B1 3.2 and - 0.9 =B1 2.2 mm/year, respectively. None of these values, including the slightly higher one in the near-field where noise might be highest, differs significantly from zero. Because the rates are low, even their small uncertainties permit a range of interpretations (they are consistent with both 0 and 2 mm/year at 2 sigma ). Although velocity uncertainties will be reduced by longer observation periods, the present data show little of the steady fault-parallel far-field motion which would be expected before future strike-slip earthquakes (13). However, the slightly higher near-field values may reflect a small tectonic signal, which could be more complex due to the details of the fault geometry, including the thrust segment (7). =20 Similar results emerge from analysis of continuously recording GPS sites away from the New Madrid seismic zone (NMSZ), in the presumably stable portion of North America (Fig. 3) (14). Modeling stable North America as a single rigid plate fits the site velocities well, with a mean residual of 1.0 mm/year. The misfits are not significantly reduced by assuming separate blocks east and west of the NMSZ (Fig. 3, inset), and the predicted motion across the NMSZ is indistinguishable from zero. _________________________________________________________________ =20 [LINK] Fig. 3. Locations of continuously recording GPS sites used to estimate an Euler vector for the presumably stable portion of North America. For each, the misfit between the observed velocity and that predicted for a single plate is shown. (Inset) Euler poles for the eastern and western subsets of the sites (divided by dashed line in main panel) compared with that for the entire set. Because the poles for the east and west data overlap at 95% confidence, the platewide GPS data show no resolvable motion across the NMSZ. [View Larger Version of this Image (45K GIF file)] _________________________________________________________________ =20 These results have implications for earthquake recurrence. It has been assumed that the 1811-1812 earthquakes were magnitude 8 events, with 5 to 10 m of horizontal slip (2). On the basis of that assumption, earlier geodetic results that found surprisingly rapid near-field strain accumulation, about one-third to two-thirds of that for the San Andreas fault system, were interpreted as consistent with 500- to 800-year recurrence for such great earthquakes (15). Our lower estimate of far-field interseismic motion, less than 2 mm/year, implies a recurrence period for such earthquakes well exceeding 2500 years (Fig. 4A). This period is a minimum because it is calculated for the maximum rate (at 2 sigma ) rather than the best fitting near-zero value, which predicts a much longer period, and is based on the assumption that all interseismic motion will be released seismically. Because deformation rates here are less than a few millimeters per year, compared with tens of millimeters per year on plate boundaries, the recurrence times for similar large earthquakes must be correspondingly longer. _________________________________________________________________ =20 [LINK] Fig. 4. (A) Relation between interseismic motion and the expected recurrence of large New Madrid earthquakes. For an assumed horizontal slip in 1811-1812 of 5 to 10 m, the geodetically observed interseismic motion of less than 2 mm/year implies recurrence times greater than 2500 years. Also shown are recurrence estimates from paleoseismic studies. The paleoseismic and geodetic data are jointly consistent with slip in 1811-1812 being about 1 m, corresponding to a magnitude 7 earthquake. (B) Earthquake frequency-magnitude data for the NMSZ. Both the recent and historic (1816 to 1984) data have slopes close to 1 and predict a recurrence interval exceeding 1000 years for magnitude 7 earthquakes and 10,000 years for magnitude 8 earthquakes. Estimates are shown with 2 sigma uncertainties. [View Larger Version of this Image (37K GIF file)] _________________________________________________________________ =20 A similar conclusion emerges from estimating the recurrence of future larger earthquakes from the observed rate of smaller earthquakes (Fig. 4B) (16-18). From recent (1974 to 1998) seismicity, when the earthquake catalog should be most complete and the magnitudes have been seismologically determined, we expect magnitude 7 and 8 earthquakes on average every 1700 and 15,000 years, respectively. Similar values (1000 and 13,000 years) are predicted from consideration of the post-1816 seismicity. These estimates are consistent with our GPS results but exceed those of an earlier study (19) because of different assumptions about the magnitudes of the larger earthquakes. =20 Significantly shorter recurrence intervals of 400 to 600 years have been estimated from the geological record (20). However, the paleoseismology can be reconciled with the geodesy and frequency-magnitude relation. One possibility is that the 1811-1812 and earlier large earthquakes in the paleoseismic record were significantly smaller than previously assumed, perhaps magnitude 7 with slip of about 1 to 2 m. If so, 1 to 2 mm/year of interseismic motion would correspond to a 500- to 2000-year recurrence (Fig. 4A), consistent with the recurrence for earthquakes of this size from the frequency-magnitude relation. Although this magnitude is smaller than what was inferred from the felt area of the 1811-1812 earthquakes and the spatial extent of the paleoseismic deformation, both techniques have considerable uncertainties in estimating earthquake magnitude. Hence, we feel that smaller 1811-1812 earthquakes can reconcile the different techniques, given uncertainties. =20 It is also possible that 1811-1812-style earthquakes may never recur. If more accurate future surveys continue to find essentially no interseismic slip, we may be near the end of a seismic sequence. It has been suggested that because topography in the New Madrid region is quite subdued, the NMSZ is a feature no older than a few million years and perhaps as young as several thousand years (21). Therefore, New Madrid seismicity might be a transient feature, the present locus of intraplate strain release that migrates with time between fossil weak zones. =20 Although much remains to be learned about this intriguing example of intraplate tectonics, the present GPS data imply that 1811-1812-size earthquakes are either much smaller or far less frequent than previously assumed. In either case, it seems that the hazard from great earthquakes in the New Madrid zone has been significantly overestimated. Hence, predicted ground motions used in building design there, such as the National Seismic Hazard Maps (22) that presently show the seismic hazard there exceeding that in California, should be reduced. =20 REFERENCES AND NOTES =20 1. See the review by A. Johnston and E. Schweig, Annu. Rev. Earth Planet. Sci. 24, 339 (1996). 2. A. Johnston, Geophys. J. Int. 126, 314 (1996); 3. L. Himes, W. Stauder, R. Herrmann, Seism. Res. Lett. 59, 123 (1988); J. Chiu, A. Johnston, Y. Yang, ibid. 63, 375 (1992). 4. R. Herrmann and J. Canas, Bull. Seismol. Soc. Am. 68, 1095 (1978); R. Herrmann, J. Geophys. Res. 84, 3543 (1979). 5. L. Braile, et al., Tectonophysics 131, 1 (1986); J. Sexton, et al., Geophysics 51, 640 (1986). 6. M. L. Zoback and M. D. Zoback, Science 213, 96 (1981) ; J. Granga and R. Richardson, J. Geophys. Res. 101, 5445 (1996). 7. J. Weber, S. Stein, J. Engeln, Tectonics 17, 250 (1998). 8. The sites occupied are listed in (7), except CRVL, which was buried by the construction of a baseball field. The 1997 survey was similar to that in 1993 except for shorter (2 day) site occupations. 9. GPS data were analyzed at the University of Miami following the procedures of T. Dixon et al. [J. Geophys. Res. 102, 12017 (1997)]. We used high-precision nonfiducial satellite orbits and the Jet Propulsion Laboratory GIPSY analysis software to estimate site velocities in the ITRF-96 reference frame. Site velocities were estimated from least-squares fits to daily positions, weighted by errors following the method of Mao et al. (11). The 1991 data have higher root mean square (rms) scatters compared with 1993 and later data. Scaling the 1991 position errors with the correlations between weighted rms and white and colored noise (11) de-weights them compared with later data. 10. We subtracted motion predicted by an Euler vector in ITRF-96 for stable North America (1.16=B0S, 80.2=B0W, 0.193=B0 per million years= ) determined by inversion of GPS data from 16 continuous stations (11). This subtraction removes most network-wide motion, although a small (but not statistically significant) eastward drift remains. Whether this drift is tectonically significant is unclear; it has no effect on our velocity gradient analysis (Fig. 2) because a mean velocity is also removed. 11. Until recently, most GPS studies assumed that geodetic noise is uncorrelated in time. Recent studies show that GPS noise is time-correlated and that assuming noise is uncorrelated can underestimate velocity errors by up to an order of magnitude [ A. Mao, C. Harrison, T. Dixon, J. Geophys. Res. 104, 2797 (1999)]. 12. J. Savage and R. Burford, J. Geophys. Res. 78, 832 (1973). 13. We compared geodetic data to a model in which steady far-field motion loads a fault before earthquake rupture. This model is commonly used for plate boundaries, where space geodetic data show rates of plate motion consistent with those over millions of years, indicating that steady far-field motions give rise to episodic earthquakes [ R. Gordon and S. Stein, Science 256, 333 (1992) ; S. Stein, in Space Geodesy and Geodynamics, Geodynamics Ser. 23, D. Smith and D. Turcotte, Eds. (American Geophysical Union, Washington, DC, 1993), pp. 5-20]. Similarly, space geodetic data (for example, Fig. 3) show that plates thought to have been rigid on geological time scales are quite rigid on decadal scales. Hence, application of these ideas of steady motion to intraplate settings seems plausible but has not been demonstrated. We did not consider strain transients after the 1811-1812 earthquakes [ P. Rydelek and F. Pollitz, Geophys. Res. Lett. 21, 2303 (1994)], which predict motions larger than interseismic motion. Similarly, our geodetic approach implicitly focuses on motions due to platewide rather than locally derived stresses (6). 14. T. Dixon, A. Mao, S. Stein, Geophys. Res. Lett. 23, 3035 (1996). These results are updated here with additional sites [A. Mao, thesis, University of Miami (1998)]. 15. L. Liu, M. Zoback, and P. Segall [Science 257, 1666 (1992)] used GPS to remeasure monuments previously measured by triangulation and reported rapid strain accumulation in the southern NMSZ corresponding to 5 to 7 mm/year of slip. A similar study across the northern NMSZ found strain rates indistinguishable from zero [R. Snay, J. Ni, H. Neugebauer, in U.S. Geol. Surv. Prof. Pap. 1538-F (1994), pp. F1-F6]. Our earlier study (7), based on the first two GPS occupations of presumably more stable monuments, found a far-field rate of 3 =B1 3 mm/year (limits are from the approach used in Fig. 2), indistinguishable from zero at 2 sigma . Hence, improved geodetic techniques and longer measurements generally reveal successively slower motion, presumably because the far-field velocity is small (or zero). Because the data have uncertainties, the first two measurements typically overestimate the velocity, which successive measurements better approximate. Unless the uncertainties are well understood, the estimated velocity may appear unduly significant (11). For New Madrid, the older triangulation data were presumably less accurate than GPS because of limitations of the technique, possibly compounded by instability of shallow-rooted triangulation pillars. Moreover, for low-strain rate areas a few measurements can change triangulation results significantly [ R. Snay, J. Geophys. Res. 91, 12695 (1986)]. Our GPS surveys use deeper rooted and presumably more stable monuments and extend outside the embayment, but geodetic GPS technology was still immature in 1991. By 1993, improved GPS receivers and an improved network of global tracking sites yielded better data, as determined by better repeatability of site positions between successive days. GPS velocity analysis is also less sensitive to site-specific errors than the triangulation analysis. Therefore, we consider the GPS results here more accurate than earlier surveys. 16. Earthquake populations approximately follow log N =3D a - bM, where N is the number of earthquakes (total or annual) whose magnitude exceeds M. Because b is about 1, earthquakes of a given size are about one-tenth as numerous as those one magnitude unit smaller. Although body and surface wave magnitudes do not exceed about 6.4 and 8.4, respectively, earthquake catalogs typically show b to be about 1 because body wave magnitudes are reported for small earthquakes and surface wave magnitudes are reported for large earthquakes [ E. Okal and B. Romanowicz, Phys. Earth. Planet. Int. 87, 55 (1994)]. Hence, if the linear frequency-magnitude relation is used, magnitudes above 6.4 should be treated as surface wave magnitudes. 17. Extrapolation of the recurrence of larger earthquakes from the rate of smaller earthquakes, used because of the limited data available for earthquakes before this century, faces various uncertainties. M. Stirling, S. Wesnousky, and K. Shimazaki [Geophys. J. Int. 124, 883 (1996)] found that such extrapolation overestimates recurrence times inferred from geological data, whereas E. Triep and L. Sykes [J. Geophys. Res. 102, 9923 (1997)] found that this extrapolation underpredicts recurrence times for large intracontinental earthquakes. 18. For 1974 to 1998, the New Madrid catalog (http://elwe.ceri.memphis.edu/~seisadm) of earthquakes with seismologically determined magnitudes yields a and b values of 3.446 =B1 0.041 (1 sigma ) and 0.954 =B1 0.013. For 1816 to 1984 (beginning at 1816 excludes major aftershocks), Nuttli's catalog (http://www.eas.slu.edu/Earthquake_Center), in which body wave magnitudes before 1964 are typically inferred from the reported shaking, yields a and b values of 4.537 =B1 0.105 and 1.079 =B1 0.022. Combining the two lines predicts recurrence times (with 2 sigma uncertainties) for magnitude 7 and 8 earthquakes of about 1400 =B1 600 and 14,000 =B1 7000 years. These values seem plausible: since 1816, there have been 16 earthquakes with magnitude greater than 5 (about a 10-year recurrence), and two with magnitude greater than 6 (about a 100-year recurrence), so magnitude 7 and 8 earthquakes should have about 1000- and 10,000-year recurrences, respectively. These estimates do not depend on whether the seismogenic stresses are local or platewide in origin (5, 13). 19. A. Johnston and S. Nava [J. Geophys. Res. 90, 6737 (1985)] inferred 550- to 1100-year recurrence for earthquakes with surface wave magnitude (Ms) > 8.3. This frequent recurrence results from treating magnitude 7 earthquakes as body wave magnitude 7, and equating them to surface wave magnitude 8.3. Recent results (16) indicate that such earthquakes are better treated as surface wave magnitude 7. 20. S. Wesnousky and L. Leffler, Bull. Seismol. Soc. Am. 82, 1756 (1992); M. Tuttle and E. Schweig, Geology 23, 253 (1995); K. Kelson, et al., J. Geophys. Res. 101, 6151 (1996). 21. E. Schweig and M. Ellis, Science 264, 1308 (1994) . 22. A. Frankel et al., National Seismic Hazard Maps Documentation: U.S. Geol. Surv. Open-File Rep. 96-532 (1996). These maps assume that a magnitude 8 earthquake occurs every 1000 years at New Madrid, so the predicted peak ground acceleration expected in 50 years at 2% probability for the NMSZ exceeds that in San Francisco, and the predicted highest acceleration (exceeding 1.2g) area for the NMSZ is larger than for Los Angeles or San Francisco. 23. Supported by NASA grants NAGW-2522 and NAG5-6685. We thank R. Graves, K. Wellington, C. Bunker, K. Nolan, and C. Griffen for field assistance in the third survey; F. Farina for assistance with data processing; E. Okal and K. Mueller for helpful discussions; R. Snay and an anonymous reviewer for useful reviews; and University Navstar Consortium for technical support. =20 Volume 284, Number 5414 Issue of 23 Apr 1999, pp. 619 - 621 =A91999 by The American Association for the Advancement of Science. =20 John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ***************************************************************************= *** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: Amateur schematics from professional scientists Date: Mon, 26 Apr 1999 16:02:52 -0500 (CDT) Regarding Amateur schematics from professional scientists: I would like to go on record as a provider of "Amateur Schematics". I am a physicist and mathematician by education, but have been practicing instrumental geophysics for the last 30 years. I learned electronics because I needed to, since the instrumentation efforts always pushed the envelope of expectations and tolerances. This inherently involves drawing schematics of the electronics, even if for only one device or experiment (for which the original pencil drawing will suffice for years). But the situation changes when others want the info. The instrumentation lab at the University is certainly not a commercial enterprise, so commercial-quantity and quality and products are not expected. But the quality far exceeds commercial expectations because we fine-tune every aspect to optimize the performance within an almost ideal environment. Once something meets our goals, we let reality in, like having to power nano-radian tiltmeters from batteries for two years on remote Aleutian hills in Arctic weather. Then the schematics get modified element-by element, but no attempt is made to make a universally complete and acceptable drawing, one that can be published. Even then, things can go wrong; I once published an article on a micro-power power supply for remote seismic telemetry amplifiers in BSSA, and even after the proofs the printer cropped off a very important part of the schematic. For the current situation of sharing information with the PSN, I have been willing to share what I have within the limitations of devoting time to the effort. I have even used a minimal cad program to re-draw several pencil drawings so that they are readable. All along I have assumed that the reader had enough electronics knowledge to figure out component values when they were omitted or to correct obvious errors. But judging by the feedback, this was a mistaken philosophy. So the latest schematics I have provided are as complete and correct as the current knowledge of the device allows. But they must always be considered as "preliminary", since I have no cad program like SPICE to check their functionality or a staff of engineers to review them. Fortunately there ARE engineers on the PSN who do look at the details and provide corrections, which are always appreciated, even if they are not building the circuit. Also, some of the parameters are changed as experience with the results warrants or as the theoretical design (like the transfer function) changes. Anyone who wants the very latest version of a schematic can send me some stamps and an address label. The problem with this is that IF some modifications are being evaluated, I will not send out schematics until they are updated. (ps. JimOD: I have your stamps). An obvious solution to accommodate the non-engineer is to provide a commercial product that is ready to plug and play. Anyone got the time? I have some initiatives in this direction, but no promises. For those making their own electronics from schematics, I should send along a package of smoke, since everyone knows that smoke is an essential ingredient of circuitry, since circuits never work after the smoke stops. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: Amateur builders and Schematics in magazines Date: Mon, 26 Apr 1999 14:05:46 -0700 This is something I've thought about a bit, and I'm guilty of my share of these types of errors. The design process for amateur equipment is different than for commercially-produced units. Both approaches have opportunity for errors to creep in, but the commercial approach includes methods to detect and eliminate those errors before they get into the released documentation. Since many amateur equipment designers are also designers by day, we forget that those checks and balances are not in place. Some things I could do to reduce mistakes (they might apply to others too): 1. Start with a written specification as the design goal. It can be modified later, but at least start with something. 2. Have a critical design review. Find someone else that is willing to review the design and critique it. 3. Be more thorough about documenting changes made to the circuit during testing. 4. Consider what sources of components the average builder will have available. 5. Try to anticipate what subtleties of construction I might do one way that someone else might do differently, and document them where it will matter. Many designers (myself included) enjoy circuit design and breadboard testing far more than they do documentation. People who want to build from this documentation get short changed. Ted, your point is well taken. I'm sure many hours of frustration have needlessly been spent when the designer has made a seemingly innocent (or not so innocent) mistake. I think that copious checking (tedious as it may be) and review by others could go along way to reduce aggravation and extend the hobby to others who have been put off by such errors. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: David Josephson Subject: Re: Amateur builders and Schematics in magazines Date: Mon, 26 Apr 1999 14:47:41 -0700 (PDT) Ted Blank writes > user-friendly, with interactive editors, breakpoints, etc. The average > joe who builds a circuit from a magazine isn't going to have a scope or > know how to debug someone elses mistake. > > I guess I'm asking this group (of probably some of the best hands-on > designers and builders of amateur science devices in the world) - why is > it so difficult to publish a diagram without errors and how can it be Sean-Thomas made an excellent and somewhat reserved reply to this question, I have only a few things to add. Most of my experience has been in helping users modify or install geophysical instruments in the field, or to build audio equipment for recording. Basically, the experimenter should never consider a drawing to be a cookbook recipe. One needn't have an EE background to understand Ohm's law and semiconductor operation. I guess the tradeoff is that when someone describes a circuit, it is an invitation to join in the development effort at that point. It may or may not be complete, tested, optimal etc and unless advertised as such no one should expect it to be! A VOM and a basic oscilloscope should be considered just as much parts of the circuit as the things on the parts list, unless it's like Larry's boards or kits, in which case you're joining the production effort rather than the developmnt effort. -- David Josephson / Josephson Engineering / San Jose CA / david@............. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "James M Hannon" Subject: Re: New sensors on line. Date: Mon, 26 Apr 1999 16:53:23 -0500 Arron, I have been thinking about a sensor along the same idea as your modified geophone. In my design I am planning on starting with a loudspeaker magnet assembly rather than a geophone. It looks like most of the parts will be easy to make except for the springs. Hopefully I will be able to photo etch some springs as soon as I can convince my toy CAD program to draw some nice spirals. :) I want to end up with a nice compact device that I can evacuate too see how much convection current and barometric pressure noise I can eliminate. Anyway, in looking at the "circuit for capacitive position detection" on your web page I noticed (according to the schematic) you are sampling the modulated signal only for 25% of the time avaliable right after the signal is changed by PHI. It would take a bit more logic but it would be much better to sample for 75% of the time avaliable starting at the 25% point. This would do two things. It would eliminate the sampling circuits seeing transients around the switching time and allow the signal to be average for three times longer. Both of these things will eliminate noise from the signal. Am I missing something? I would replace the HA7210 74HC74 and 74LS21 with a PIC MicroChip processor programmed to supply the 3 timing signals. Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: CARRJJ@....... Subject: Re: Amateur schematics from professional scientists Date: Mon, 26 Apr 1999 18:10:12 EDT Visio Technical 3, 4 or 5 will do a nice job of drawing electronic circuit diagrams. I used it for my books and articles on electronics. Joseph J. Carr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: CARRJJ@....... Subject: Re: Amateur builders and Schematics in magazines Date: Mon, 26 Apr 1999 18:12:56 EDT You might want to see my column "Open Channel" in the current edition of Nuts 'n' Volts for a design approach. Joseph J. Carr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ted Blank Subject: Re: Amateur schematics from professional scientists Date: Mon, 26 Apr 1999 15:20:40 -0700 (PDT) I hope nobody on this list thinks I'm shooting at them. My comments were directed at magazine articles which get published with no way to make corrections. The web is changing everything for the better. Actually I would prefer if magazines didn't even publish schematics, but just gave a URL. Then I would wait a few months for the more advanced builders to try things out and get their feedback to the author, after which he would (hopefully) update the web page. Here's the deal - a magazine article which profices a schematic, plus part numbers and manufacturers names, plus (in some cases) Radio Shack catalog numbers, is a big invitation that says "build me!" OK, so I've been dumb enough to accept the invitation a few times, but never with good results. (There have been a few other invitations I've turned down over the years, probably for the better, but we won't get into that.) I don't blame anyone but myself trying to cross into disciplines where I'm not trained. But if as I suspect it is not possible to publish an error-free schematic in a general circ. magazine, why dont' they just stop trying? I don't mean to pick on Scientific American here, but their schematics are usually the only ones I figure are "dumbed down" enough for the likes of me. The frustration comes with the territory - amateur science is by nature interdisciplinary. And that means you learn new stuff or get out of the hobby. I still remember trying to build my first A/D on a prototype board for the IBM XT. (Memorialized in the EMON.OPT file as the Burr-Brown homemade A/D board, number 0). I called the board manufacturer for help reducing noise, and I'll never forget his advice: "Just sprinkle capacitors all over the board." Clearly there was some shared knowledge assumed there which I was lacking at the time. But I've enjoyed being stretched in many new directions over the years. I like the fact that Larry is selling a pre-packaged amplifier, since that's the biggest inhibitor to more PSN sites (IMHO). If Sean-Thomas sells prepackaged sensors some day, I'll buy one of those too, so I can record good quality data while I tinker with my own constructions. Smoke injectors to reactivate dead parts...there's a thought. Ted Blank San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ted Blank Subject: Re: Amateur builders and Schematics in magazines Date: Mon, 26 Apr 1999 15:35:43 -0700 (PDT) David Josephson, well put. On the PSN, I think we all agree that publication of a schematic constitutes "an invitation to join in the design process." For a mass market magazine, one has to assume the audience will expect the design process (including technology for publishing error-free drawings!) is complete. So my tolerance for bugs in schematics goes way down in the latter environment. Ted Blank San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rex Klopfenstein, Jr." Subject: Re: VBB parameters Date: Mon, 26 Apr 1999 20:05:33 -0400 S-T Morrissey wrote: > Rex, > > The integrator periods should work out to 1,10,20,40,80, and 80 seconds. > After reading you note, I did some more calculations. Everything seems to 'add up' except for two resistor values: The first is the 3rd resistor (266.41K) in the Rp switch. Shouldn't it be 226K? The other resistor value I have a question on is the last resistor (3242K) on the Ri switch. If you want 80 seconds wouldn't that resistor be about 1/2 the listed value (1621K). I have added your Ri & Rp equations to my MathCAD model so when I get my VBB built and calibrated I just plug in the values and let the computer do the grunt work. Now I just have to get other projects done so that I can get on the machines to build the VBB. -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: Amateur schematics from professional scientists Date: Mon, 26 Apr 1999 19:05:42 -0700 Then there are those of us who listen to the circuit descriptions and think they can add a little and improve the circuit without understanding the circuit completely . A while back I was having a problem with oscillations of my newest VBB sensor . Despite Sean's comment about adding nothing between the amp and the triple feedback components, I added a single pole LP, thinking it would limit noise, but I think all it added was a phase shift which I think started the oscillations. By elliminating it as I had done on a previous version, the oscillations stopped :) Regards Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: SW6079@....... Subject: Re: Amateur builders and Schematics in magazines Date: Mon, 26 Apr 1999 21:38:41 EDT I got a real chuckle out of your post, Ted. I have been a Ham for about 25 years now and have been following your psychology of waiting a few months also. For some real horrifying errors try reading "Practical Electronic Circuits" I don't know how these happen either. One solution would be to give the author editing capacity prior to publication. But if you have ever met an editor, you know how likely that is! _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: PSpice Date: Mon, 26 Apr 1999 22:18:05 -0700 Sean Thomas mentioned Spice and I was wondering, I have used Pspice in the past, but am not sure how to model mechanical in with electrical components. I would like to model the VBB with Pspice but I am not sure how the mechanical part of the sensor is incorporated into the analysis. Any thoughts or help? Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: More on GPS Date: Tue, 27 Apr 1999 00:38:09 -0700 Hi Everyone, Last week I received one of Pete Ouellette GPS antennas (http://www.sawcenter.com/gpsant.htm) and the ONCORE interface board offered by TAPR (http://www.tapr.org/tapr/html/Ftac2.html). Both work great. The antenna is as good, if not a little better, then the Motorola antenna and its $32.00 cheaper. The TAPR interface board is mostly built and tested. But too get it to work with SDR one jumper needs to be added. The is to send the 1 pps signal out to the DCD RS-232 signal line. Other then that, all that is needed is a DC power, anything between 7 to 30 volts. The board has a switching power supply, so it produces very little heat. I was going to use a standard 5 volt regulator that needed a small heat sink... Since this board only has the 1 pps signal on the DCD line, I modified SDR so that the 1 pps can come from either the TTL input or the DCD line. I will release this version of SDR in a few days. Thanks to everyone who responded to my GPS position question. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: JIm Hannon Subject: Re: PSpice Date: Tue, 27 Apr 1999 06:17:55 -0500 barry lotz wrote: > Sean Thomas mentioned Spice and I was wondering, I have used Pspice in > the past, but am not sure how to model mechanical in with electrical > components. I would like to model the VBB with Pspice but I am not sure > how the mechanical part of the sensor is incorporated into the analysis. > Any thoughts or help? > Barry > > Barry, I worked on this for a while last year and did not finish the work. One way to use spice for mechanical parts is to come up with an equivalent electrical circuit for the mechanical parts. I tried this with Sean's equations for the VBB and found that it was not possible to come up with an equivalent circuit for the equation in question. I did not pursue it any further but I think it is possible to insert the equations more directly into Spice and use the results in the rest of the circuit. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: JDE@............. (John D. Edison) Subject: Leaving Date: Tue, 27 Apr 1999 08:33:52 > leave PSN-L Thank You > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "James M Hannon" Subject: Re: Amateur builders and Schematics in magazines Date: Tue, 27 Apr 1999 07:27:41 -0500 It has been my experience that most of the errors in published schematics come from transcription errors. That is someone has to take the original schematic from the designer and redraw it. The task of checking the results is quite boring and tedious and is often skipped. Over the years here at work we have evolved from hand drawn schematics translated into hand drawn pc board layouts and rehand drawn published schematics to CAD drawn schematics electronically translated into PC layouts and publication schematics. This has reduced the number of errors in the final products dramatically. Now the only one left to blame for errors is the designer :( Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: Re[2]: GPS position question Date: Tue, 27 Apr 1999 09:11:22 -0700 (MST) On Fri, 23 Apr 1999, angel rodriguez wrote: > I have a friend in Newport (near LA) that took a lab for geology class > and it included a be of this and I guess what they do is have points > marked all over the place and visit the places regularly and take a > reading at that point and then go back to the lab and do post > processing and that done over time gives very accurate results. The > point are nails driven in parking lots and sidewalks and most anyplace > from what she told me. It is better than usual data, but it is instructive to look at some papers done using GPS to see the error ellipses, which are uncertainties in the velocity of the landmarks (spikes or whatever). They are often fairly large errors that are only washed out when the velocities are very high or the readings are taken over a multitude of years (which duplicates a higher velocity)... John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Charles R. Patton" Subject: Re: PSpice Date: Tue, 27 Apr 1999 09:14:52 -0700 Barry wrote: >I would like to model the VBB with Pspice but I am not sure >how the mechanical part of the sensor is incorporated into the analysis. >Any thoughts or help? One article that had a complete table of electrical/mechanical equivalents for SPICE was: "Resonant Loads On the Space Station=92s Rotary Joint Velocity Loop" by Lauren V. Merritt at Lockheed Missiles & Space Company Inc. It appeared on pages 8-17 of the July/August 1993 issue of "MOTION" magazine. I=92ll scan the chart when I get home and post them on a web page. Charles R. Patton charles.r.patton@........ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: PSpice Date: Tue, 27 Apr 1999 10:28:23 -0700 Barry -- I've never tried to model the VBB system as an electronic circuit but it should be possible to do so, at least the first-order effects. A lot of effort has been put into modeling mechanical systems with electronic circuit simulation software. Electronic analogs of the mechanical components have been developed, and many spice libraries contain such things. Complex mechanical systems such as aircraft control surface hydraulic actuators and feedback systems have been modeled using spice. From Dynamics, by J. L. Meriam, John Wiley & Sons 1971, come the following Mechanical-Electrical equivalents: -Mechancial- -Electical- Mass Inductance Spring Constant 1/Capacitance Force Voltage Velocity Current Displacement Charge Damping Resistance Here's the approach I would try to get spice to model it: The mass-spring system in most seismometers can be described by a second-order differential equation, and a series LRC circuit is described by the same equation form with different coefficients. In the mechanical system, the equation is as follows : F = m*x(double-dot) + c*x(dot) + k*x where F is the force applied to the mass (gravity + earth acceleration + feedback force), m is the magnitude of the mass, c is the damping coefficient (from friction), k is the spring constant, and x is the displacement of the mass. The equivalent electronic system is: V = L*q(double-dot) + R*q(dot) + (1/C)*q where V is the voltage across the entire LRC circuit, L is the value of the inductor, R is the value of the resistor, C is the value of the capacitor, and q is the charge flowing through the circuit (which is the integral of current). To practical things... Model the mass-spring system as a series LRC. R can be zero for the time being, but if you know the Q of the actual mechanical system, you can calculate a non-zero R. Model the force on the mass (which is the sum of gravity, earth accelerations, and the force from the feedback coil) as a voltage source across the total LRC circuit. The value of the mass in kg is the inductance in Henrys. The recripocal of the spring constant in N/m is the capacitance in Farads. Any friction you can identify in Newtons/(meter/second) is the resistance in ohms. The force from the feedback coil is proporational to the current flowing through it. The model of the feedback coil is a resistor (8 ohms, or whatever you have) and a series voltage source whose value is a function of the velocity (time derivative of displacement) of the mass. Depending on how thorough you want to be, you might want to model this voltage source also. Now the tricky part. If your spice system has a way to monitor the current flowing in the circuit, good. Take that current and integrate it with respect to time in seconds (if your spice system allows math to be performed on quantities such as this). The output of the integral (in volts) is the displacement of the mass (in meters) which gets fed to the displacement detector. If your spice system doesn't allow current monitoring or integration, put in another series resistor of insignificant value (.000001 ohms, perhaps) and monitor the voltage across that resistor. Use an op-amp amplifier if you have to. Then integrate that -- use an op-amp integrator if you have to (with components such that 1 volt in gets you 1 volt/second out) -- and feed it to the displacement detector. I don't think I'd try to model the entire displacement detector with spice. I'd model the output stage of it to include any filtering, but I wouldn't try to model the ac part. I would feed the displacement signal above through an amplifier with the appropriate gain to simulate the gain of the displacement transducer and feed it to the output stage of the displacement transducer, and then on to the rest of the VBB feedback system. This is the point that, without really doing it, I run short of information. I hope that others will fill in what I got wrong or left out. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... At 10:18 PM 4/26/99 -0700, you wrote: >Sean Thomas mentioned Spice and I was wondering, I have used Pspice in >the past, but am not sure how to model mechanical in with electrical >components. I would like to model the VBB with Pspice but I am not sure >how the mechanical part of the sensor is incorporated into the analysis. >Any thoughts or help? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: CARRJJ@....... Subject: Re: Amateur builders and Schematics in magazines Date: Tue, 27 Apr 1999 18:25:02 EDT I can add something to the comments on letting authors check their proofs before publication having written some 700 articles. Only a very, very few mass market magazines do that. For example, Electronics World/Wireless World and Elektor Electronics both send proofs (is it relevant that both are published in the UK). Others never send proofs. EW/WW's editor sends me zip compressed pdf files and requires a response (if I want to get paid). Some magazines actually have a technical editor on board who knows enough to question bad information in an article text or drawing. In other cases, poor tech editors make changes they should not make. One, for example, reversed the labels "diastolic" and "systolic" in my drawing of the human arterial blood pressure waveform, making me look like a fool. TAB Books was LEGENDARY in their mistakes....and they never, ever sent proofs to the author. BTW, I do a seminar called "Publish, Don't Perish" for academic audiiences. If anyone would like the PowerPoint slides and Word-97 text let me know and I'll send it. You must be using Windows 3.1, 95, 98 or NT to open the file. Joseph J. Carr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Re: New Madrid Fault Zone Article Date: Tue, 27 Apr 1999 14:08:38 -0700 John Hernlund wrote: > > Below is an article from Friday's "Science" issue that claims a lower > seismic hazard for the New Madrid Seismic zone based on an empirical > "frequency-magnitude" relation (also called the Gutenberg-Richter Law) and > measurements that show little or no motion in the surrounding areas. I think > their model is grossly oversimplified, but it is still interesting to read > over... Also, the frequency-magnitude relation parameters change over time > and do not usually work for quakes much larger than 5.0 (these fit the model > the worst, the best fit is mostly between 3.0 and 5.0). > I spent several years monitoring movement on major faults in California. There was plenty of movement on the central portion of the San Andreas, where we had regular modest (=< 5+) earthquakes. There was absolutely no movement in Marin County, home of the 1906 San Francisco EQ and no movement in the Tehachapi leg, center of the 1857 Ft. Tejon EQ. In either of these instances, the lack of movement coincided with recent big earthquakes. You can argue that there was no movement because it didn't need to (because of recent history) or you can argue that lack of movement indicates strain is building for another big one, but I don't think you can argue that lack of movement is contraindicative of future earthquakes. Doug Crice _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: PSpice Date: Tue, 27 Apr 1999 18:55:34 -0700 Thanks Jim and Charles for your input. I have several Motion issues but they don't go back that far. Barry Charles R. Patton wrote: > snip-- > One article that had a complete table of electrical/mechanical > equivalents for SPICE was: > "Resonant Loads On the Space Station=92s Rotary Joint Velocity Loop" > by Lauren V. Merritt > at Lockheed Missiles & Space Company Inc. > It appeared on pages 8-17 of the July/August 1993 issue of "MOTION" > magazine. > > I=92ll scan the chart when I get home and post them on a web page. > > Charles R. Patton > charles.r.patton@........ > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: New Madrid Fault Zone Article Date: Tue, 27 Apr 1999 19:08:01 -0700 Doug I did a statistical study of events in Calif from 1800+ to 1990 a few years back (incomplete). I noticed a definite lack of events in the areas you describe. I also saw a lack of activity in the Owens valley area. I compared "current " activity with the potential of activity previously recorded, figuring if ,for whatever reason, there was an event previously then there was the potential of a similar sized reoccurance. I won't get to wordy here but would be glad to discuss it with you further. As a side note I looked at zones of activity rather than specific fault lines. Regards Barry Doug Crice wrote: > > I spent several years monitoring movement on major faults in > California. There was plenty of movement on the central portion of the > San Andreas, where we had regular modest (=< 5+) earthquakes. There was > absolutely no movement in Marin County, home of the 1906 San Francisco > EQ and no movement in the Tehachapi leg, center of the 1857 Ft. Tejon > EQ. In either of these instances, the lack of movement coincided with > recent big earthquakes. You can argue that there was no movement > because it didn't need to (because of recent history) or you can argue > that lack of movement indicates strain is building for another big one, > but I don't think you can argue that lack of movement is > contraindicative of future earthquakes. > > Doug Crice > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: meredith lamb Subject: Refrigerators as makeshift seismo covers/containers Date: Tue, 27 Apr 1999 23:29:59 -0600 Hi all, With the demise of my old refrigerator and its pending disposition I naturally have pondered whether a part could be successfully used as a seismo cover. The upper freezer part with its separate door looks vaguely possible to detach and use. I imagine it would be a bear to saw to separate the freezer part from the refrigerator part, and would be ragged edges, but if it was set in fresh concrete just enough to allow door clearance, it would be relatively air movement free and temperature effective. The inside bottom central area would likely have to be removed and filled with concrete at the same time as the other concrete is poured (for the solid surface for the seismo to rest on). Like the rubber/magnetic strips around the inside door to close the metal contacts and seal it. Somehow I didn't notice them before. Don't know the "R" insulatin value, but with the ready frame, one could add on the outside and inside as room allows. Anyway........ha.......it could be possible. Anyone tried this before? Yes....I've heard of barrels and drums........ . I suppose the metal frame sides being partially buried in the concrete would have an effect on the "pier" to some degree. Stretching the subject a hair further, the door itself could make a nice door for a crawlspace "vault", of some fashion. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Walt Williams" Subject: PSN-L: Refrigerators as makeshift seismo covers/containers Date: Tue, 27 Apr 1999 23:32:40 -0800 Hello Meredith, >Meredith I imagine it would be a bear to saw to separate the freezer part from the refrigerator part, and would be ragged edges,... >Walt May I suggest that you use a 'saws-all'? This would cut through a refrigerator like butter and not leave a nasty jagged edge. You can probably rent these saws. I watched my brother cut through an 1 foot I-beam in about ten minutes, on one blade and it was a clean cut. Best Wishes, Walt Williams, 99.04.27 =========================================== ------- Forwarded Message Follows ------- Date: Tue, 27 Apr 1999 23:29:59 -0600 From: meredith lamb To: "psn-l@.............." Subject: Refrigerators as makeshift seismo covers/containers Reply-to: PSN-L Mailing List Hi all, With the demise of my old refrigerator and its pending disposition I naturally have pondered whether a part could be successfully used as a seismo cover. The upper freezer part with its separate door looks vaguely possible to detach and use. I imagine it would be a bear to saw to separate the freezer part from the refrigerator part, and would be ragged edges, but if it was set in fresh concrete just enough to allow door clearance, it would be relatively air movement free and temperature effective. The inside bottom central area would likely have to be removed and filled with concrete at the same time as the other concrete is poured (for the solid surface for the seismo to rest on). Like the rubber/magnetic strips around the inside door to close the metal contacts and seal it. Somehow I didn't notice them before. Don't know the "R" insulatin value, but with the ready frame, one could add on the outside and inside as room allows. Anyway........ha.......it could be possible. Anyone tried this before? Yes....I've heard of barrels and drums........ . I suppose the metal frame sides being partially buried in the concrete would have an effect on the "pier" to some degree. Stretching the subject a hair further, the door itself could make a nice door for a crawlspace "vault", of some fashion. Meredith Lamb _________________________________________________________________ ____ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Charles R. Patton" Subject: Re: PSpice Date: Tue, 27 Apr 1999 23:37:34 -0700 Barry and others interested in SPICE mechanical/electrical analogs. I=92ve posted a scan of the page I mentioned at: http://www.pe.net/~crpatton/spice.gif Copy URL exactly as otherwise you=92ll get error messages as there are no= HTML pages there. The GIF is about 59K as the I had to scan at 300 DPI because the original left something to be desired. Hope it helps. Charles R. Patton charles.r.patton@........ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Re: Refrigerators as makeshift seismo covers/containers Date: Wed, 28 Apr 1999 00:19:18 -0700 meredith lamb wrote: > used as a seismo cover. The upper freezer part with its separate > door looks vaguely possible to detach and use. I imagine it > would be a bear to saw to separate the freezer part from the > refrigerator part, and would be ragged edges, but if it was set > in fresh concrete just enough to allow door clearance, it would > be relatively air movement free and temperature effective. A couple of thoughts. Maybe consider putting the door on top so gravity helps to keep it closed? Probably easier access unless you pour the concrete really high. Reciprocating saws are very good at cutting metal. I used one to cut a rusty suspension part off of my old beater car. My dad bought an old fridge/freezer to hold old paint cans. It works pretty good and it costs less than a fire safe. When the door is closed you can't smell anything in it. I know a fire safe is probably safer. ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Re: New Madrid Fault Zone Article Date: Wed, 28 Apr 1999 08:38:38 -0700 Barry, I have been out of touch with earthquake research, having spent the last 25 years in exploration geophysics, but I was shocked that anybody would reach the conclusions in the article at this late date. It appears that we can agree that regular small earthquakes coincide with fault displacement. Seems kind of obvious, but how can you argue that lack of small earthquakes and lack of fault displacement preclude earthquakes in historically active areas. The Carrizo Plains segment of the San Andreas has moved many times over recent geologic history (you can see that from 20,000 feet) but has been lacking in both displacement and small earthquake. -- barry lotz wrote: > > Doug > I did a statistical study of events in Calif from 1800+ to 1990 a few years > back (incomplete). I noticed a definite lack of events in the areas you describe. I > also saw a lack of activity in the Owens valley area. I compared "current " > activity with the potential of activity previously recorded, figuring if ,for > whatever reason, there was an event previously then there was the potential of a > similar sized reoccurance. I won't get to wordy here but would be glad to discuss > it with you further. As a side note I looked at zones of activity rather than > specific fault lines. > Regards > Barry > > Doug Crice wrote: > > > > > I spent several years monitoring movement on major faults in > > California. There was plenty of movement on the central portion of the > > San Andreas, where we had regular modest (=< 5+) earthquakes. There was > > absolutely no movement in Marin County, home of the 1906 San Francisco > > EQ and no movement in the Tehachapi leg, center of the 1857 Ft. Tejon > > EQ. In either of these instances, the lack of movement coincided with > > recent big earthquakes. You can argue that there was no movement > > because it didn't need to (because of recent history) or you can argue > > that lack of movement indicates strain is building for another big one, > > but I don't think you can argue that lack of movement is > > contraindicative of future earthquakes. > > > > Doug Crice > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rex Klopfenstein, Jr." Subject: O.T. - C/L Meter Suggestions Date: Wed, 28 Apr 1999 12:52:48 -0400 I have been thinking about buying a cap/ind digital meter for some time now. Finally I have a 'real' need. Can anybody make suggestions. I am willing to pay a little more for accuracy. Thanks in advance -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Re: O.T. - C/L Meter Suggestions Date: Wed, 28 Apr 1999 09:57:01 -0700 Rex Klopfenstein, Jr. wrote: > > I have been thinking about buying a cap/ind digital meter for some time now. Finally I have a 'real' need. Can anybody make suggestions. I am willing to pay a little more for accuracy. > My impression is that eBay is a good place to buy test equipment. You can search for what you want and I think they have an e-mail notification that something has come up. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: New Madrid Fault Zone Article Date: Wed, 28 Apr 1999 11:03:45 -0700 (MST) On Tue, 27 Apr 1999, Doug Crice wrote: > I spent several years monitoring movement on major faults in > California. There was plenty of movement on the central portion of the > San Andreas, where we had regular modest (=< 5+) earthquakes. There was > absolutely no movement in Marin County, home of the 1906 San Francisco > EQ and no movement in the Tehachapi leg, center of the 1857 Ft. Tejon > EQ. In either of these instances, the lack of movement coincided with > recent big earthquakes. You can argue that there was no movement > because it didn't need to (because of recent history) or you can argue > that lack of movement indicates strain is building for another big one, > but I don't think you can argue that lack of movement is > contraindicative of future earthquakes. Right. There is also a weird section along the San Andreas just north of Parkfield where a locked zone (no movement) adjoins a creeping segment (lots of motion). This is problematic, because nobody that I have heard about can find out what is happening between these two zones that accomodates the apparent accumulation of strain at the interface, or even see evidence of this strain at the surface. There is also some interesting recent work on moving strain waves that propagate by transferring stress and relaxation along the lithosphere-asthenosphere mushy contact. How this works is a great earthquake will cause a local relaxation of stress, which then allows the region next to it to relax also. The whole lithosphere then adjusts by viscous relaxation in the asthenosphere, which shuttles the lithosphereic plates around. This strain wave moves away from the great quake with a speed that should be regulated by the viscosity of the asthenosphere. For a good article on this, see: Fred F. Pollitz, Roland Burgmann, and Barbara Romanowicz. Viscosity of Oceanic Asthenosphere Inferred from Remote Triggering of Earthquakes. Science, 1998 May 22; 280: 1245-1249. They claim to see a swarm of activity moving from Alaska southward after the great earthquake there. This would correspond to a strain accumulation rippling out southward as the lithosphere readjusted itself for the displacement of the earthquake. They use a model of this to estimate the viscosity of the lithosphere... If anyone wants a copy of a reprint (pdf format) of this article I can put one in my web directory. This kind of thing further complicates our ability to judge how a particular segment of fault will behave, because it is then tied into the stress and strain field of the entire planet...as distant events can cause eventual increased activity remotely. The great earthquakes on the New Madrid are certainly anomalous, and just like other strange events occurring on our planet they probably cannot be treated so simplistically. I don't think their estimates of recurrence intervals are any better or worse than those made previously. John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Taber Subject: Re: New Madrid Fault Zone Article Date: Thu, 29 Apr 1999 09:26:07 +1200 (NZST) On 28 Apr, Doug Crice wrote: > I was shocked that anybody would > reach the conclusions in the article at this late date. > > It appears that we can agree that regular small earthquakes coincide > with fault displacement. Seems kind of obvious, but how can you argue > that lack of small earthquakes and lack of fault displacement preclude > earthquakes in historically active areas. The Carrizo Plains segment of > the San Andreas has moved many times over recent geologic history (you > can see that from 20,000 feet) but has been lacking in both displacement > and small earthquake. I may have read the article too quickly, but I thought the point was that there was negligible strain accumulation over the entire region as measured using GPS. In the case of a locked fault like sections of the San Andreas or the Alpine Fault here in New Zealand, strain (deformation) is observable over the region, just not right across the fault. It is possible to generate locked fault models that match the observed surface distribution of compression and extension. John Taber _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: O.T. - C/L Meter Suggestions Date: Wed, 28 Apr 1999 16:59:26 -0700 Rex -- At work, we recently bought an LRC meter from IET Labs. It has worked just fine with two exceptions: The 9-volt battery doesn't last very long (a couple of weeks in lab use of 2-3 times per day), and it died when we connected it to an electrolytic capacitor with about 10 volts charge on it. They sent us a new one a half price. Although I couldn't connect just now, their web page used to be at http://www.ietlabs.com . Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... At 12:52 PM 4/28/99 -0400, you wrote: >I have been thinking about buying a cap/ind digital meter for some time >now. Finally I have a 'real' need. Can anybody make suggestions. I am >willing to pay a little more for accuracy. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Digital Cameras Date: Thu, 29 Apr 1999 00:17:23 -0700 Hi All, A little off topic.... I'm look for a still frame digital camera to document things like Aaron's experiment on the web. I have a nice 35 mm camera, but it needs to be repaired. I also would like to get the instant gratification offered by a digital camera and not have to wait a whole hour for film development or longer if the photo store is closed. If you have one and are either happy or unhappy with it, can you let me know? I think I'm looking for one that has over 1024X786 pixels but if you have one with less pixels and you find it works fine let me know... Thanks, -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Re: Digital Cameras Date: Thu, 29 Apr 1999 05:17:32 -0700 Larry, I have had a digital camera for some time, an Olympus D-320L. At the time, I did quite a bit of research and chose this one. Of course the price droped about 40% in the next few months. Here's my comments: 1. The best feature about digital cameras is not so much that you don't have to wait an hour for developing, but that you don't have to wait for the end of the roll. You can take one or two pictures and download them--for free. Some of us can't stand to waste a whole roll of film. 2. You are correct that 1024 is nice, though I find that the pictures taken at 1024 are pretty big (because the computer equates pixels with screen size) and I often end up either resampling or cropping the pictures. I tend to use 1024 as a substitue for zoom (which I don't have and miss quite a bit). For color prints, 1024 is obviously better, for computer applications, not so important. You certainly don't want to put a megapixel photo on the web for downloading at an alleged 56K. 3. These is such a range of features and price that you kind of get what you pay for with digital cameras (on that particular day of course, because the price will be cheaper tomorrow). I found a number of web sites with reviews of digital cameras, particularly the Ziff Davis computer site. Besides the obvious differences, different brands handle colors differently, and it's nice to compare outputs. 4. There is a photo-editing program called LView Pro which you can download. If you like it, they ask you to register and pay about $25. It's a very good program, robust and feature rich. Try it before you buy an expensive one. Larry Cochrane wrote: > > A little off topic.... I'm look for a still frame digital camera to > document things like Aaron's experiment on the web. I have a nice 35 mm > camera, but it needs to be repaired. I also would like to get the instant > gratification offered by a digital camera and not have to wait a whole hour > for film development or longer if the photo store is closed. > > If you have one and are either happy or unhappy with it, can you let me > know? I think I'm looking for one that has over 1024X786 pixels but if you > have one with less pixels and you find it works fine let me know... > > Thanks, > > -Larry Cochrane > Redwood City, PSN > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: angel rodriguez Subject: Re: Digital Cameras Date: Thu, 29 Apr 1999 08:26:57 -0500 Hello Larry, Thursday, April 29, 1999, 2:17:23 AM, you wrote: LC> A little off topic.... I'm look for a still frame digital camera to LC> document things like Aaron's experiment on the web. I have a nice 35 mm LC> camera, but it needs to be repaired. I also would like to get the instant LC> gratification offered by a digital camera and not have to wait a whole hour LC> for film development or longer if the photo store is closed. I have Sony Mavica with the 10X zoom. I like this camera a lot. It's easy to get the pic to the computer, because you use a regular diskett for storage. No cable, no mess. Sometimes I take pictures for friend and just hadn them the diskett. They have several models and one of them is for the screen size you want even thought for just internet stuff I don't think you will need it. I end up cropping most of the stuff I take anyway and the save it at a resolution of 72 or 96. It is a bit pricey!! Best regards, Angel mailto:angel@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: DGentry509@....... Subject: Re: Digital Cameras Date: Thu, 29 Apr 1999 09:46:45 EDT Check out www.play.com for the Snappy unit to capture video from your cam corder or other simple devise. Delux version of 3.0 has audio capture also. Sites Q&A has all the answers. About $139 or less. Costco has for $124 plus tax. This unit can snag video from even a kids low cost game like a Vega and a lot of others. Converts the analog signal to about 1500 horizontal and interpolates the vertical rate to about 1200 or so. Just read and memory is failing. Unit will take a scanner input also. This version will allow B/W or Color editing. Think I'll get dressed and go get one. Don Gentry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: browning Subject: Re: Digital Cameras Date: Thu, 29 Apr 1999 10:45:51 -0400 Hello, Some observations about digital cameras. I have several that I use for web pages and advertising. The higher resolution is worth the price because as you use them, you find that you want to do more with them (just like computers). If you're use to film cameras, you need the resolution to so you won't be disappointed when you print them. Flash is nice to have because although digitals will shoot in low light, mine seem to get a little grainier if the focus isn't in the sweet zone (while in low light). I use a 600 X 800 for messing around and under the right conditions it will do fine work for the web but the 1000 X 1200 will look much sharper under less than ideal conditions. Also for extreme close-ups, the resolution really helps. Zoom is GREAT! A camera that works well for me is a kodak dc120. Although you need to buy a sun card to beef up the number of exposures and like all, it eats batteries. I paid 400 for a Ricoh RDC2E (600X800) and 6 months later 359 for the Kodak DC 120 (1000X1200). The Kodak has zoom and flash, the Ricoh doesn't. I like the direct to floppys but couldn't fine one with zoom, flash and high resolution for under 900 so I stayed with the cable connection. If you can, borrow several and try them out. Good luck, Lou Browning _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: robert barns <75612.2635@..............> Subject: Digital Cameras Date: Thu, 29 Apr 1999 11:33:50 -0400 Larry, I got a Kodak DC-120 digital camera several weeks ago and have found it= quite satisfactory. You can see many examples on my web site = www.webspan.net/~bbarns I got it "reconditioned" from Kodak for $400. (Our local camera store i= s asking $800!) You also need the wall-wart for ~$60 because dumping pics from the camera uses a lot of battery. Li batteries are expensive but thier higher capacity makes them more economical than alkalines. See specs. on the DC-120 at www.kodak.com The 3X optical zoom and mac= ro capabilities are good. Pics come out of the camera in .BMP format and are 3.7 meg each regardless of the resolution setting in the camera. I use LVEIW to edit the .BMP files and convert them to .JPG. This is highly compressed and t= he pics on my web site are between 7 and 40k. Bob Barns = _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Re: Digital Cameras Date: Thu, 29 Apr 1999 10:18:28 -0700 Larry Cochrane wrote: > A little off topic.... I'm look for a still frame digital camera to I recently sold my 35 mm camera. I was going to get a digital, but I chickened out and just upgraded my computer instead. Anyway I was looking at a Nikon. I think this ones about $900-1000. http://www.nikonusa.com/products/new0218/cp950/coolpix950.html There's a review link on the page. Plus I hadn't totally made up my mind. I guess I wanted the faster computer more. They also have: http://www.nikonusa.com/products/new0218/cp700/coolpix700.html I think this ones about $500-600. Which to me is a bargain for 1600x1200 with 8 MB included. I had trouble finding a dealer for these also. Good luck, Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rex Klopfenstein, Jr." Subject: VBB Question (Quad Amp Circuit) Date: Thu, 29 Apr 1999 21:36:14 -0400 Sean I have one more question on the quad amp circuit. There is a resistor and capacitor which is an optional input attentuator on the last op amp. My question is what values do I use if I don't want to do any attentuation? Thanks in advance -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: vbb corrections Date: Fri, 30 Apr 1999 01:00:58 -0500 (CDT) Rex, You will be happy to know that I am trying to get all the ducks in a row by making a list of all the drawings and schematics by date and latest version number. It might mitigate the confusion somewhat. Regarding your questions: Have you checked TUCKER electronics about a used LCR meter? THeir prices are reasonable and they can provide calibration. The resistor values on the multi-period schematic should be as you asked. THe 266.41k should be 226.41, a typo. THe 3242k should be half that at 1621k; the value was left over from another option. Thanks for the corrections. On the quad amp circuit, omitting the resistor to common at the input to any of the amplifiers eliminates the attenuation. The capacitor is for noise control. But don't lock in the values around A1, the displacement amp, yet, because I am still uncomfortable with the phase shift problem (of response to high frequencies vs short period instability). In my note of 25 April on solving the mathcad equations, I said that RI is found by solving the TI equation, but I wanted to say that the Tn equation is solved, but the result is the same, as you have probably figured out. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: Beograd quake Date: Fri, 30 Apr 1999 08:40:22 +0200 A med. quake occured this morning in Serbya. Ml 6.0 with epicentre near = Beograd.=20 No significant material damnages, but the news is not very reliable = because of the censorship on the information....! The lats days we have registered other 3 vents, located in = Albania-Kossovo border region max 4.0 Francesco Nucera I.E.S.N. PSN ITALY
A med. quake occured this morning in Serbya. Ml 6.0  with = epicentre=20 near Beograd.
No significant material damnages, but the news is not very reliable = because=20 of the censorship on the information....!
The lats days we have registered other 3 vents, located in = Albania-Kossovo=20 border region max 4.0
 
Francesco Nucera
I.E.S.N.   PSN ITALY
From: angel rodriguez Subject: Re[2]: PSN-L Digest for 17 Apr 1999 Date: Fri, 30 Apr 1999 20:18:41 -0500 Hello John, Monday, April 19, 1999, 12:05:47 PM, you wrote: JL> Dennis Pope writes: "I am installing a Guralp CMG-PEPPV." JL> Dennis, JL> How much did this instrument cost you? JL> Thanks, JL> JCLahr JL> _____________________________________________________________________ JL> Public Seismic Network Mailing List (PSN-L) JL> To leave this list email listserver@.............. with the body of the JL> message: leave PSN-L Angel, Sorry for my delays, quickly PEPP pricing is as follows i will fax a quote on monday: Quantity with GPS $ 1 to 10 2620-00 11 to 25 2500-00 25 to 50 2 400-00 50 to 100 2310-00 Over 100 POA Standard Delivery Times for units 1 to 50 of 90 days from order. Delivery of over 50 units on terms to be discussed Packaging $50-00 (£30-00) per unit. SCREAM! 2.0 for educational purposes $100-00 per CMG-PEPP. best regards Nathan angelr wrote: > Hello Nathan, > > Friday, April 23, 1999, 11:40:26 AM, you wrote: > > NP> Yes we can supply one i will send quotation shortly, > > NP> Please supply a fax number if possible. > > NP> best regards > > NP> Nathan > > did you ever get a chance to send that fax?? > > Best regards, > angelr mailto:angelr@............ Best regards, Angel mailto:angel@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Giovanni Rotta" Subject: from ITALY: LARGE QUAKE IN PROGRESS NOW ! Date: Sun, 2 May 1999 18:40:08 +0200 Italian stations are recording now a large quake ! Giovanni Giovanni Rotta Via F. Pizzigoni, 10 33010 Resia (Udine) I Lat. 46.373 N Long. 13.305 E rottag@.......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Giovanni Rotta" Subject: from ITALY: LARGE QUAKE IN PROGRESS Date: Sun, 2 May 1999 18:49:33 +0200 A large quake now in progress: 16:14 UTC - Ml. > 5.0 - North Atlantic ocean Giovanni Giovanni Rotta Via F. Pizzigoni, 10 33010 Resia (Udine) I Lat. 46.373 N Long. 13.305 E rottag@.......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: modified 4.5hz phones Date: Sun, 2 May 1999 12:31:05 -0500 (CDT) Aaron, You are probably busy getting ready for the SSA. I was hoping to attend, but have no funds. But I have been pushing the "earthquake" buttons to try to get you an event at your setup at Larrys; however, I have found that a watched seismograph does not quake, at least until you momentarily disconnect the digitizer or make some fatal adjustment (There has just been a moderate quake that Giovanni in Italy reports as a 5+ in the North Atlantic; the STM seis has a nice record, but the 4.5hz phones are on the bench!). I looked at your .../smssl/Geophones/... site and tried to read the last paper that you have listed there. Unfortunately, ACROBAT had some problem with the .PDF file. I even had our guru try to fix it, but to no avail. If you get a chance, maybe you have a version of your current poster that you can point me to. By the way, I have spent some time with a new 4.5 hz phone trying to reduce the suspension noise, but have not made significant (= repeatable) progress. At a Tn of 20 seconds, it is about 5 mv p-p, which at 1400V/m/sec, is about 3.6 microns/second. The microseisms are running about 1 mv p-p. So enjoy Seattle. We have a number of people attending, many of whom are micro-brew fans, so whether you see them or not ....! Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rex Klopfenstein, Jr." Subject: Basic S-G Seismometer Questions Date: Sun, 02 May 1999 19:01:04 -0400 I have just finished building two S-G's using Larry's cards. I am also using his I/O card and software (SDR). When I tuned my pickups I got about 5V out (using an oscilloscope) from each channel. My S-G's are located on the floor (2' sq patio stones mortared to floor & covered with cerm. tile) of an old cistern in my house. I have enclosed each seismometer in a double layer of 2" foam board. I have also used the same foam board to fill empty spaces on the inside of the enclosures My house is located in town and about 75-100' from a main city street I let my system run for about two weeks and looked at the max/min stored for each channel (N-S High & Low and E-W High & Low). I get values that range from about 1500 to -2000 on low frequency output and 200 to -68 on the high frequency output. Now that I think of it, I have checked the zero lately! I have a few questions for the S-G experts out there! First, do these values sound right? What would be good starting values to set triggers. What output (high or low) would you put them on to pick up teleseismic events without getting a lot of false triggers from such local seismic events like someone flushing the basement toilet or door slams! -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: The Lahrs Subject: Seismograms Date: Sun, 02 May 1999 20:08:46 -0600 In case anyone is interested in making daily seismograms of data from their seismic station, I've added information to my web site on the software that I'm using. The program is called sudsdrum. It was written by Robert Banfill for the International Association of Seismology and Physics of the Earth's Interior (IASPEI) Software Library. I'm starting with files generated by DaTaq's WinDAQ software, but this method could be adapted to other formats as well. See http://lahr.org/john-jan/psn/gldn_psn.html John * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * AOL version of homepage: * * http://lahr.org/john-jan/homepage.html * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: meredith lamb Subject: Re: Basic S-G Seismometer Questions Date: Sun, 02 May 1999 20:57:57 -0600 "Rex Klopfenstein, Jr." wrote: > I have a few questions for the S-G experts out there! First, do these > values sound right? What would be good starting values to set > triggers. What output (high or low) would you put them on to pick up > teleseismic events without getting a lot of false triggers from such > local seismic events like someone flushing the basement toilet or door > slams! Rex, Congrats on the 2 S-G's being up and running. I run 2 also, but mine are the Hall sensor type, and different than yours. Obviously your trigger/s will have to run above the local noise, or you will record alot of noise. It will likely be a trial and error routine over some time, and include any seasonal abberations. For me, and endless changes of the trigger, I more or less got to the point, where I leave it alone and take what comes...and of course....miss the lower level quakes often. I use my vertical coil & magnet seismo for the trigger for all.... its much less sensitive to the "noises" of the horizontals. I use 800 in the winter and lower it in the summer to around 400. (OK....my Atlantic quake recording today was because Giovanni rotta, made the quake alert message, and I hit the "E" button....ha....after turning on the monitor power and reviewing....seriously) Your stated values are probably correct for the average range. I think you will see alot of "false" triggers no matter what you do with the horizontals trigger/s settings. I think I would start with about 900, and go from there up or down with what your locale permits, but this is of course just a wild guess. Will be looking forward to seeing your seismograms. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re[2]: winquake bugs?? Date: Sun, 02 May 1999 23:00:48 -0700 Hi WinQuake Users, Angel is having a problem with WQ and FFTs. Can anyone else repeat this? I can't repeat it on my system. He's using NT like myself. Thanks, -Larry Cochrane Redwood City, PSN >Date: Fri, 30 Apr 1999 05:59:46 -0500 >From: angel rodriguez >X-Mailer: The Bat! (v1.22) UNREG >Reply-To: angel rodriguez >To: Larry Cochrane >Subject: Re[2]: winquake bugs?? > >Hi Larry, > >Here is the portion of the Error log for the last time WinQuake closed itself. I use the last version you posted which I down loaded in the full verison and installed it on this machine keeping my tables and data files. > >To get this error I loaded Winquake and opened a folder, which I call >qtemp, which is not the default folder. I chose the first event and did an FFT then chose bandpass from 1 to 5 then chose the time domain display and then clicked on the close box for the displayed event. > >I'm getting this all the time, the only safe place I have found is the default folder. > >If I can be more specific or send more of the event and error logs, let me know. I hope this helps. > >regards, > >angel > >******************************* >Program version > >32-Bit WinQuake version 2.6.1 Beta >Release date 2/2/99 > >******************************* > >Application exception occurred: > App: (pid=224) > When: 4/30/1999 @ 4:40:31.93 > Exception number: c0000005 (access violation) > > *----> System Information <----* > Computer Name: 78NAD21 > User Name: Arodrig > Number of Processors: 1 > Processor Type: x86 Family 6 Model 6 Stepping 10 > Windows Version: 4.0 > Current Build: 1381 > Service Pack: 4 > Current Type: Uniprocessor Free > Registered Organization: REI > Registered Owner: IS > > *----> Task List <----* > 0 Idle.exe > 2 System.exe > 21 smss.exe > 24 CSRSS.exe > 35 WINLOGON.exe > 41 SERVICES.exe > 44 LSASS.exe > 73 SPOOLSS.exe > 71 mwmdmsvc.exe > 81 mwssw32.exe > 98 amgrsrvc.exe > 102 DrvMgr.exe > 107 Mcshield.exe > 46 VsTskMgr.exe > 121 RPCSS.exe > 135 TAPISRV.exe > 142 TPCHRSRV.exe > 146 RASMAN.exe > 189 NDDEAGNT.exe > 148 EXPLORER.exe > 124 systray.exe > 149 LOADWC.exe > 125 shstat.exe > 191 point32.exe > 197 CWD3DSnd.exe > 202 cardview.exe > 206 mswheel.exe > 193 OSA.exe > 178 NTVDM.exe > 224 winqk32.exe > 268 DRWTSN32.exe _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: Basic S-G Seismometer Questions Date: Sun, 02 May 1999 23:54:21 -0700 Rex, On your low frequency output port; The 1500 & -2000 count number seem high if these numbers are the background noise during a quiet time and over a short period of time. I would adjust the gain so that you get around +-100 counts of background noise over a few minutes of time during a quiet time like late at night. Obviously if someone walks near the sensor the max count level will go up way over +-100 counts. Your high frequency port should also be set for about the same background count level. Hope this helps. -Larry Cochrane Redwood City, PSN At 07:01 PM 5/2/99 -0400, you wrote: >I have just finished building two S-G's using Larry's cards. I am also >using his I/O card and software (SDR). When I tuned my pickups I got >about 5V out (using an oscilloscope) from each channel. > >My S-G's are located on the floor (2' sq patio stones mortared to floor >& covered with cerm. tile) of an old cistern in my house. I have >enclosed each seismometer in a double layer of 2" foam board. I have >also used the same foam board to fill empty spaces on the inside of the >enclosures > >My house is located in town and about 75-100' from a main city street > >I let my system run for about two weeks and looked at the max/min stored >for each channel (N-S High & Low and E-W High & Low). I get values that >range from about 1500 to -2000 on low frequency output and 200 to -68 on >the high frequency output. Now that I think of it, I have checked the >zero lately! > >I have a few questions for the S-G experts out there! First, do these >values sound right? What would be good starting values to set >triggers. What output (high or low) would you put them on to pick up >teleseismic events without getting a lot of false triggers from such >local seismic events like someone flushing the basement toilet or door >slams! > >-- >Rex Klopfenstein, Jr. >Bowling Green, OH >rklopfen@......... >www.wcnet.org/~rklopfen > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: angel rodriguez Subject: Re[3]: winquake bugs?? Date: Mon, 3 May 1999 07:31:06 -0500 Hello Larry, Monday, May 03, 1999, 1:00:48 AM, you wrote: LC> Hi WinQuake Users, LC> Angel is having a problem with WQ and FFTs. Can anyone else repeat this? I LC> can't repeat it on my system. He's using NT like myself. LC> Thanks, LC> -Larry Cochrane Last night I noticed that I have the problem when I'm n folders that have names like "Quake temp" or "AAA Q junk" . If I rename those folders with names like "9906" or "9999" the problem seems to go away. angel _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: angel rodriguez Subject: Re: Basic S-G Seismometer Questions Date: Mon, 3 May 1999 07:41:06 -0500 HI Rex, You worte: RKJ> I have a few questions for the S-G experts out there! First, do these RKJ> values sound right? What would be good starting values to set RKJ> triggers. What output (high or low) would you put them on to pick up RKJ> teleseismic events without getting a lot of false triggers from such RKJ> local seismic events like someone flushing the basement toilet or door RKJ> slams! My triggering ideas changed when I read a report from a Costa Rica station the had 153 triggred events in 40 hours and only 13 were real quakes. I loweedr my levels and do get much more junk. I trigger 20 or more times a day. I also am detecting many more smaller quakes. I get mostly local stuff. I'm also getting good at glancing at most of the stuff and throwing it out. Some times I think I'm in some sort of global teleseismic shadow. I get very little far away stuff. angel _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ted Blank Subject: Re: modified 4.5hz phones Date: Mon, 3 May 1999 09:56:04 -0700 (PDT) Sean-Thomas, you are very perceptive to notice that adjustments to a sensor which would *improve* its performance or sensitivity never trigger any quake activity, only (and I love this term) "fatal adjustments"... which of course you never learn were fatal until after the quake... Ted Blank San Jose, California On Sun, 2 May 1999, S-T Morrissey wrote: > Aaron, > > You are probably busy getting ready for the SSA. I was hoping to attend, > but have no funds. But I have been pushing the "earthquake" buttons to > try to get you an event at your setup at Larrys; however, I have found > that a watched seismograph does not quake, at least until you > momentarily disconnect the digitizer or make some fatal adjustment > (There has just been a moderate quake that Giovanni in Italy reports as > a 5+ in the North Atlantic; the STM seis has a nice record, but the > 4.5hz phones are on the bench!). > > I looked at your .../smssl/Geophones/... site and tried to read the > last paper that you have listed there. Unfortunately, ACROBAT had some > problem with the .PDF file. I even had our guru try to fix it, but to > no avail. If you get a chance, maybe you have a version of your current > poster that you can point me to. > > By the way, I have spent some time with a new 4.5 hz phone trying to reduce > the suspension noise, but have not made significant (= repeatable) progress. > At a Tn of 20 seconds, it is about 5 mv p-p, which at 1400V/m/sec, is > about 3.6 microns/second. The microseisms are running about 1 mv p-p. > > So enjoy Seattle. We have a number of people attending, many of whom > are micro-brew fans, so whether you see them or not ....! > > Regards, > Sean-Thomas > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Nick & Sophie Caporossi Subject: Noise to signal ratio Date: Mon, 03 May 1999 14:09:14 -0400 Hi All: I am at a loss as to why I can't improve my noise to signal ratio. Am running into a snag with the third sensor. First: All three are built with the same material and design. ( Lehman type) They have about the same natural frequency, (about 20 seconds). They are damped about the same. They all have the same type of magnet.(a 22 pound pull, mounted on the boom) They are setup in the same proximity to each other. (about 3 feet part) They are mounted in the basement, where it's free drafts and has a constant temperature. Second: The difference: The third sensor has a coil made of #49 gauge wire It has 19,200 turns. The other sensors are using 8k turns of #36 gauge wire. I also used a 6k turns coil, all coils work well when interchanged with the other sensors. I increase the mass from 3 pounds to 4 and 1/2 pounds. On the first 2 sensors, the boom is made of solid aluminum bar.(about 3/8 diam.) This current one, the boom is made of an Aluminum tube. (1/2 diam.) It is not as rigid as the solid one, but still it is quite strong. The problem: The third sensor does not work as well. The noise to signal ratio is about 1/5 that of the other ones. There is an increase the natural back ground noise. It has more gain than the other two. It is not sensitive to house noises, wind and other external vibrations. Could the following be the cause? a)Is it the Knife edge at the pivot that is causing too much friction? I changed for razor blade to an "exact O" blade. The blade is about 3/8 of an inch wide. b)Is it the additional weight on the boom causing the Aluminum tube to flex, causing more noise and less signal strength? I moved the sensors around to eliminate the possibility the iron was the problem but to no avail. I'm at a loss to come up with a solutions. Any suggestions would be appreciated. Thanks Nick _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: angel rodriguez Subject: Re: Noise to signal ratio Date: Mon, 3 May 1999 15:58:46 -0500 Hello Nick, Monday, May 03, 1999, 1:09:14 PM, you wrote: NSC> Hi All: NSC> I am at a loss as to why I can't improve my noise to signal ratio. I was have a devil of a time a while back with oe of my lehman sensors and finaly decided that it was the wire holding the boom up. It was too too thin and my horizontal was acting like a verticle. I left a very short portion of the thin wire at the top and made the rest of the support stiffer. Just a guess! Best regards, Angel mailto:angel@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "James M Hannon" Subject: Re: tornados and seismo Date: Tue, 4 May 1999 16:33:58 -0500 I just ran across another little tidbit of info on tornados and seismic signals. See http://www.enn.com/ENN-News-Archive/1997/04/041897/04189712.asp Jim Hannon "Stephen Caruso" on 04/12/99 11:00:35 PM Please respond to PSN-L Mailing List To: "PSN-L Mailing List" cc: Subject: tornados and seismo Has anybody ever followed up on the seismic interpretation of a tornado? We have a network of 14 seismos in Ohio now. Is there a way to interpret this data? Perhaps an excel file or PIE chart config? Stephen Caruso _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rex Klopfenstein, Jr" Subject: Re: Basic S-G Seismometer Questions Date: Tue, 04 May 1999 21:23:22 -0400 Larry Cochrane wrote: > Rex, > > On your low frequency output port; The 1500 & -2000 count number seem high > if these numbers are the background noise during a quiet time and over a > short period of time. I would adjust the gain so that you get around +-100 > counts of background noise over a few minutes of time during a quiet time > like late at night. Obviously if someone walks near the sensor the max > count level will go up way over +-100 counts. I assume that you mean the R5 pot (Low Out) and the R41 pot (High Out) listed in your SG schematic _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rex Klopfenstein, Jr" Subject: VBB High Pass Filter Question Date: Tue, 04 May 1999 21:40:24 -0400 Sean I have a question on the design of the high pass filter used in the output of the VBB. What is the design cutoff frequency? I seem to remember reading in your article that you were using 5 Hz., is that true? What R value did you use in the high pass design? I am having a hard time finding 2000 mfd capacitors to used to 'make' the 1000 mfd high pass capacitor. The closest seems to be 2200 mfd which works out to 1100 mfd. Also, all can find is +/-20% elect. Any suggestions? Rex Klopfenstein, Jr. Bowling Green, OH _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: 5/5 Event? Date: Wed, 05 May 1999 17:55:31 -0700 I haven't seen anything @ USGS yet but Red Puma says Alabama??? or Mexico @ around 22:30:00. I recorded an event but can anyone confirm location? Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Seisguy@....... Subject: Re: 5/5 Event? Date: Wed, 5 May 1999 20:56:40 EDT In a message dated 5/5/99 7:53:31 PM EST, gbl@....... writes: > I haven't seen anything @ USGS yet but Red Puma says Alabama??? or > Mexico @ around 22:30:00. I recorded an event but can anyone confirm > location? > Barry The following is from the United States Geological Survey, National Earthquake Information Center: preliminary hypocenter for earthquake of 1999 may 05, OFF COAST OF CHIAPAS, MEXICO, about 130 miles (210 km) SSW of Tonala, Chiapas, Mexico: latitude 14.4 degrees north longitude 94.5 degrees west origin time 22 41 29.7 utc depth normal, magnitude 5.6 mb. stations used: ltx p 224527.8 lpig p 224535.9 dwpf p 224541.5 miar p 224601.4 oxf p 224605.8 wmok p 224607.6 sftn p 224613.0 twar p 224613.5 pwla p 224613.7 goga p 224615.5 cwpt p 224622.8 relt p 224623.4 glst p 224626.3 mync p 224628.4 anmo p 224635.1 tuc p 224636.0 wci p 224649.4 cbks p 224650.8 ceh p 224655.3 wuaz p 224701.5 rw3 p 224707.1 gld p 224710.6 isco p 224712.7 sjg p 224713.8 pfo p 224715.4 knb p 224719.3 mcwv p 224720.5 mtpc p 224722.0 sru p 224723.2 jfws p 224724.6 msu p 224725.9 arut p 224727.1 tpnv p 224735.2 sspa p 224735.2 dau p 224735.9 wjpm p 224738.0 abl p 224738.7 ctu p 224739.8 dug p 224740.4 noq p 224741.2 rssd p 224743.9 tph p 224746.5 bw06 p 224747.4 ptrm p 224749.1 mtum p 224749.5 nna p 224751.5 hvu p 224751.8 biny p 224753.6 mnv p 224754.0 elk p 224754.6 redw p 224756.5 hayw p 224757.1 lrv p 224757.9 pti p 224758.0 tmi p 224759.6 lsct p 224800.9 stew p 224801.0 grai p 224801.0 sao p 224801.1 cmb p 224802.4 lkwy p 224805.0 cvr p 224806.4 eymn p 224806.7 lkc p 224810.3 ohcm p 224815.5 nshm p 224817.0 wvor p 224820.1 hops p 224822.4 lbnh p 224824.0 wdc p 224825.0 ybh p 224833.2 kbrm p 224836.2 lnor p 224839.4 hso p 224845.6 hawa p 224846.9 ssor p 224850.4 new p 224851.3 dpw p 224852.9 cor p 224853.4 shw p 224856.9 lon p 224859.3 bmw p 224902.6 lpaz p 224905.3 ocwa p 224915.0 yka p 225022.7 bdfb p 225059.1 plca p 225128.5 opa p 225136.8 kip p 225137.2 kdc p 225141.2 slkm p 225141.5 cola p 225147.2 spu p 225148.9 rso p 225149.3 tta p 225203.2 sdn p 225204.8 adk p 225302.1 smy p 225333.2 pab p 225345.9 kono p 225403.5 pym p 225405.5 thef p 225411.4 kev p 225412.3 sle p 225419.8 dbic p 225419.8 obn p 225510.3 bosa p 230024.4 lbtb p 230024.6 ------------------------------------- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: Re: 5/5 Event? Date: Wed, 5 May 1999 20:00:29 -0500 (CDT) The USGS says a M 5.6 of the coast of Chiapas, Mexico at 14.4N and 94.5 W at 22:41:29.7. The VBB data showed some very clean 60-second surface waves. S-TM. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: 5/5 Event? Date: Wed, 05 May 1999 18:26:08 -0700 Sean Thomas I uploaded my VBB event file. You may have been asked this before, but is there a way for us to review your event files? Maybe ASCII? I for one would like to compare my VBB response with yours to see where my frequency content may be lacking. Barry S-T Morrissey wrote: > The USGS says a M 5.6 of the coast of Chiapas, Mexico at 14.4N and > 94.5 W at 22:41:29.7. > > The VBB data showed some very clean 60-second surface waves. > > S-TM. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: Re: 5/5 Event? Date: Thu, 6 May 1999 00:29:05 -0500 (CDT) Barry, I would be happy to make an ASCII event file and put it on the web page somewhere ... if I had the data. Unfortunately, my 90-second VBB is only recording on the fax-paper monitor drum because I am using my single-channel digitizer (the RS multimeter) for the experimental 4.5hz>20Second VBB. I haven't looked at that data yet, but I expect that the event is lost in the noise, which is running 5 to 10 millivolts (about 7 microns/second) on a windy day. Someday I will buy one of Larry's digitizers so I can record everything of interest, including temperature, pressure, and mass position. I have to put this old home machine (486dx50) out to pasture soon, and it will make a fine machine for digitizing. And once I am running SDR, the data will be readily available. In the mean time, if an event occurs when I have the 90-second connected, I will plot it with MATHCAD and scan it and post it. I haven't posted any recently. Is there any event that you particularly want to see?. I have a nice record of the last M5.8 off Chiapas last June; it is very similar to todays' event. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: Re: VBB High Pass Filter Question Date: Thu, 6 May 1999 00:48:43 -0500 (CDT) Rex, The high pass filter from the VBB output to the line amplifiers to the recorder or digitizer is intended to remove the DC offset of the VBB signal from the data. THis offset can be large, even with commercial instruments, and can quickly saturate a 16-bit digitizer or make the traces cross over or simply be out of range on an analog recorder. The filter values are not at all critical. I use 1000 to 2000 uf into an amplifier with an input resistance of 100k ohms. This is a time constant of 100 to 200 seconds, which is outside the flat velocity passband of the VBB response. But the single pole rolls off as 1/omega, so even 5 minute barometric fronts are still well recorded. Of course, if the amplifier input resistor is 1 meg ohm, very long periods, like duirnal thermal effects, will be passed. The Aluminum electrolytics used back-to-back are good even if they are 20% tolerance since any change of the response of the high-pass filter will generally not affect the data of interest. And your observation that 2200uf prevails over 2000uf is correct, although I get 2000uf Sprague AL electrolytics from NEWARK. For filtering out "cultural" noise, like trucks, pets, me, and the clothes washer, a low pass filter around 5 hz is necessary for my installation in the basement about 10 meters from a busy street. Someone with a better site without these noises can have a higher cut- off frequency. In my line driver amplifier, I have two poles of 0.47 uf and about 470k ohms in the amplifier feedback, and 2 x 0.47 uf with 100k at the amplifier input. I also have a low-pass filter in the old drum recorder amplifier. As before, these values are not particularly critical for me for experimental evaluations, since I am mostly interested in the long-period response. The 5-hz rolloff is quite clear in the calibration data. I suppose that the amplifier documentation should eventually be tidied up with the filters properly designed and described with transfer functions. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Northern California PSN members... Date: Thu, 06 May 1999 01:19:24 -0700 Hi N. Cal. PSNers, Yesterday I talked to Dave Nelson (our New Zealand station?) on the phone. He will be visiting N. Cal. next Monday and / or Tuesday. He was wondering if it was possible to get together with some of the local members. I'm game for a local "unofficial" PSN meeting next week. Maybe we could have dinner at a restaurant somewhere around here. Let me know if your interested and sorry of the short notice... -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ken Navarre Subject: Re: Northern California PSN members... Date: Thu, 6 May 1999 01:48:28 -0700 (PDT) On Thu, 6 May 1999, Larry Cochrane wrote: > Yesterday I talked to Dave Nelson (our New Zealand station?) on the phone. > He will be visiting N. Cal. next Monday and / or Tuesday. He was wondering > if it was possible to get together with some of the local members. I'm game > for a local "unofficial" PSN meeting next week. Maybe we could have dinner > at a restaurant somewhere around here. > > Let me know if your interested and sorry of the short notice... Let me know when & where. I'll see if I can make it. Ken _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Phil Giannini Subject: Impromptu PSN meeting Date: Thu, 06 May 1999 07:15:29 -0700 Hi Guys, I will be in SoCal on business until monday evening, but if the meeting happens on tuesday I might be able to go. I will be watching here for a place and time and I will try to attend. Thanks, Phil SFN&Z _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "dave nelson" Subject: Re: Impromptu PSN meeting Date: Thu, 06 May 1999 08:59:52 PDT hi all at this stage a monday dinner would be the best for me as im also going right through to oregon and have to be back in LA area by friday, so im running a pretty tight schedule. if we can meet several of u that would be great if not then another time, as i am planning on immigration to the USA by the end of 1999. John Lahr and Ed Cranswick if ur reading this too. i plan to be in denver area (aurora) from the 19 may for ~3 days b4 going on to missouri and ohio. so hoping to meet u guys too. i will be staying at friends in canton, ohio for ~1.5 months b4 returning to LA and flying out of the US back to NZ. immigration MUST be applied for via the US consulate in ur home country. cheers Dave Nelson the temporarily displaced NZ PSN co-ordinator :) _______________________________________________________________ Get Free Email and Do More On The Web. Visit http://www.msn.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: Impromptu PSN meeting Date: Thu, 6 May 1999 10:58:28 -0600 (MDT) Dave, Good to hear that you will be coming out this way. I'll be around. We should have a PSN dinner, for sure. Edward, Merideth, and Dewayne: which night would be best? JCLahr ################################## John C. Lahr ################################# Seismologist ################################ U.S. Geological Survey ############################### Geologic Hazards Team, MS966 ############################## PO Box 25046 #############################/############################## ############################/############################### Denver, Colorado 80225-0046 ################################ Phone: (303) 273-8596 ################################## Fax: (303) 273-8600 ################################### lahr@........ ##################################### http://giseis.alaska.edu/lahr http://lahr.org/john-jan _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: AutoDRM Date: Thu, 6 May 1999 11:00:59 -0600 (MDT) Does anyone have a PC program for reading AutoDRM Email data from the USGS NEIC? If not, I'll try to compile one. Thanks, JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Re: AutoDRM Date: Thu, 06 May 1999 11:34:40 -0700 John Lahr wrote: > > Does anyone have a PC program for reading AutoDRM Email data from > the USGS NEIC? If not, I'll try to compile one. I think Arie (SP?) from Austrailia and Larry were working on that. It might be in the newest version of WinQuake? I forget. ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brandon Skogen Subject: Re: AutoDRM Date: Thu, 6 May 1999 11:37:22 -0700 (PDT) not me. Sorry. Brandon M. Skogen/ISCRV _________________________________________________________ Do You Yahoo!? Get your free @......... address at http://mail.yahoo.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "James M Hannon" Subject: Re: AutoDRM Date: Thu, 6 May 1999 13:49:36 -0500 Have a look at Arie's web page at http://www.iinet.net.au/~ajbv/AutoDRM/AutoDRM.html Jim Hannon John Lahr on 05/06/99 12:00:59 PM Please respond to PSN-L Mailing List To: psn-l@.............. cc: Subject: Re: AutoDRM Does anyone have a PC program for reading AutoDRM Email data from the USGS NEIC? If not, I'll try to compile one. Thanks, JCLahr _____________________________________________________________________ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: AutoDRM Date: Thu, 6 May 1999 13:51:47 -0600 (MDT) Thanks, Jim. Arie has quite a good site and a DOS conversion program for GSE2.0/CM6 data to PSN format. JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: jfroom@............ Subject: Northern Cal PSN Meeting Date: Thu, 6 May 99 13:08:56 PDT I'll be available, let me know when and where.... Jan Froom _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Wayne Abraham J73WA Subject: Re: AutoDRM Date: Thu, 06 May 1999 16:27:20 -0400 John The latest version of Winquake supports AutoDRM. Wayne John Lahr wrote: > Does anyone have a PC program for reading AutoDRM Email data from > the USGS NEIC? If not, I'll try to compile one. > > Thanks, > JCLahr > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Wayne Abraham 1430 Rodney Street Portsmouth, Dominica abrahamw@........ http://www.freeyellow.com/members6/dominicapsn/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: R: AutoDRM Date: Fri, 7 May 1999 00:21:42 +0200 WQ new release supports AutoDRM with GSE2.0 extension Francesco =FF=FE<=00!=00D=00O=00C=00T=00Y=00P=00E=00 =00H=00T=00M=00L=00 = =00P=00U=00B=00L=00I=00C=00 = =00"=00-=00/=00/=00W=003=00C=00/=00/=00D=00T=00D=00 =00H=00T=00M=00L=00 = =004=00.=000=00 = =00T=00r=00a=00n=00s=00i=00t=00i=00o=00n=00a=00l=00/=00/=00E=00N=00"=00>=00= =0D=00=0A= =00<=00H=00T=00M=00L=00>=00<=00H=00E=00A=00D=00>=00=0D=00=0A= =00<=00M=00E=00T=00A=00 = =00c=00o=00n=00t=00e=00n=00t=00=3D=00"=00t=00e=00x=00t=00/=00h=00t=00m=00= l=00;=00 = =00c=00h=00a=00r=00s=00e=00t=00=3D=00u=00n=00i=00c=00o=00d=00e=00"=00 = =00h=00t=00t=00p=00-=00e=00q=00u=00i=00v=00=3D=00C=00o=00n=00t=00e=00n=00= t=00-=00T=00y=00p=00e=00>=00=0D=00=0A= =00<=00M=00E=00T=00A=00 = =00c=00o=00n=00t=00e=00n=00t=00=3D=00"=00M=00S=00H=00T=00M=00L=00 = =005=00.=000=000=00.=002=000=001=004=00.=002=001=000=00"=00 = =00n=00a=00m=00e=00=3D=00G=00E=00N=00E=00R=00A=00T=00O=00R=00>=00=0D=00=0A= =00<=00S=00T=00Y=00L=00E=00>=00<=00/=00S=00T=00Y=00L=00E=00>=00=0D=00=0A= =00<=00/=00H=00E=00A=00D=00>=00=0D=00=0A= =00<=00B=00O=00D=00Y=00 = =00b=00g=00C=00o=00l=00o=00r=00=3D=00#=00f=00f=00f=00f=00f=00f=00>=00=0D=00=0A= =00<=00D=00I=00V=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=002=00>=00W=00Q=00 =00n=00e=00w=00 = =00r=00e=00l=00e=00a=00s=00e=00 =00s=00u=00p=00p=00o=00r=00t=00s=00 = =00A=00u=00t=00o=00D=00R=00M=00 =00w=00i=00t=00h=00 = =00G=00S=00E=002=00.=000=00 =00=0D=00=0A= =00e=00x=00t=00e=00n=00s=00i=00o=00n=00<=00/=00F=00O=00N=00T=00>=00<=00/=00= D=00I=00V=00>=00=0D=00=0A= =00<=00D=00I=00V=00>=00&=00n=00b=00s=00p=00;=00<=00/=00D=00I=00V=00>=00=0D= =00=0A= =00<=00D=00I=00V=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=002=00>=00F=00r=00a=00n=00c=00e=00s=00c=00o=00<=00= /=00F=00O=00N=00T=00>=00<=00/=00D=00I=00V=00>=00<=00/=00B=00O=00D=00Y=00>= =00<=00/=00H=00T=00M=00L=00>=00=0D=00=0A= =00 From: "Francesco" Subject: MATLAB Date: Fri, 7 May 1999 00:24:17 +0200 Who knows where I can find some seismologist toolbox for Matlab, = expecially for acquisition and data record? Francesco Nucera
Who knows where I can find some seismologist toolbox for Matlab, = expecially=20 for acquisition and data record?
 
Francesco Nucera
From: Larry Cochrane Subject: Re: Impromptu PSN meeting Date: Thu, 06 May 1999 21:51:10 -0700 So it looks like Monday would be best for Dave. Any suggestions as too where we should meet? If we want to meet around Redwood City we could have it at Harry's Houfbrau on El Camino Real. If most of the people are coming from the San Jose area we could have it somewhere down there... -Larry Cochrane Redwood City, PSN At 08:59 AM 5/6/99 PDT, you wrote: > >hi all > at this stage a monday dinner would be the best for me >as im also going right through to oregon and have to be back in LA area by >friday, so im running a pretty tight schedule. > > if we can meet several of u that would be great if not then another >time, as i am planning on immigration to the USA by the end of 1999. > > >John Lahr and Ed Cranswick if ur reading this too. i plan to be in denver >area (aurora) from the 19 may for ~3 days b4 going on to missouri and ohio. > so hoping to meet u guys too. > > i will be staying at friends in canton, ohio for ~1.5 months b4 returning >to LA and flying out of the US back to NZ. >immigration MUST be applied for via the US consulate in ur home country. > >cheers >Dave Nelson >the temporarily displaced >NZ PSN co-ordinator >:) > > >_______________________________________________________________ >Get Free Email and Do More On The Web. Visit http://www.msn.com > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: 5/5 Event? Date: Thu, 06 May 1999 22:03:29 -0700 S-T Morrissey wrote: ---snip ---- > In the mean time, if an event occurs when I have the 90-second connected, > I will plot it with MATHCAD and scan it and post it. I haven't posted any > recently. Is there any event that you particularly want to see?. I have > a nice record of the last M5.8 off Chiapas last June; it is very similar > to todays' event. > > Regards, > Sean-Thomas > Sean Thomas Any teleseismic event would be nice to see. Since the info would be graphical, an FFT in a linear amplitude vertical scale would be nice. I think this would be very informative. Regards Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ted Blank Subject: Re: Impromptu PSN meeting Date: Thu, 6 May 1999 22:08:13 -0700 (PDT) I'd like to come, we may be looking at offers on our house Monday but anyway I'll try to make it. I've never been to the Gordon Biersch Brewery in San Jose but I hear it is nice. Hopefully by end of July we will be settled in Portsmouth, NH. Will miss the Bay Area and all my PSN friends. Haven't found a house to move to yet though, so we may be staying one week with each member of PSN. No wait, all PSN members who have extra bedrooms have them full of equipment. "We have reserved the Lehman Bedroom for you, Mr. & Mrs. Blank. Behave yourselves or we'll put a recording of your nighttime activities on the PSN." :-) Ted Blank San Jose, California On Thu, 6 May 1999, Larry Cochrane wrote: > So it looks like Monday would be best for Dave. Any suggestions as too > where we should meet? If we want to meet around Redwood City we could have > it at Harry's Houfbrau on El Camino Real. If most of the people are coming > from the San Jose area we could have it somewhere down there... > > -Larry Cochrane > Redwood City, PSN > > At 08:59 AM 5/6/99 PDT, you wrote: > > > >hi all > > at this stage a monday dinner would be the best for me > >as im also going right through to oregon and have to be back in LA area by > >friday, so im running a pretty tight schedule. > > > > if we can meet several of u that would be great if not then another > >time, as i am planning on immigration to the USA by the end of 1999. > > > > > >John Lahr and Ed Cranswick if ur reading this too. i plan to be in denver > >area (aurora) from the 19 may for ~3 days b4 going on to missouri and ohio. > > so hoping to meet u guys too. > > > > i will be staying at friends in canton, ohio for ~1.5 months b4 returning > >to LA and flying out of the US back to NZ. > >immigration MUST be applied for via the US consulate in ur home country. > > > >cheers > >Dave Nelson > >the temporarily displaced > >NZ PSN co-ordinator > >:) > > > > > >_______________________________________________________________ > >Get Free Email and Do More On The Web. Visit http://www.msn.com > > > >_____________________________________________________________________ > > > >Public Seismic Network Mailing List (PSN-L) > > > >To leave this list email listserver@.............. with the body of the > >message: leave PSN-L > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: AutoDRM Date: Fri, 7 May 1999 08:57:08 -0600 (MDT) Hi Wayne and Francesco, I'm always amazed at the features in WinQuake! Looks like between WinQuake and Arie's conversion program, there is no problem with GSE2.0-formatted messages. Now I'm working on GSE1.0-formatted data, as that's what NEIC generates for their AutoDRM messages. JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brandon Skogen Subject: Re: AutoDRM Date: Fri, 7 May 1999 08:40:44 -0700 (PDT) Any one have any info on Mount St. helens? Brandon M. Skogen/ISCRV _________________________________________________________ Do You Yahoo!? Get your free @......... address at http://mail.yahoo.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: TMichel917@....... Subject: Re: MATLAB Date: Fri, 7 May 1999 12:28:23 EDT Hi Francesco, there are two seismologist toolboxes for MATLAB. The first is "MATSEIS", a GUI controlled MATLAB package of seismic data visualisation, processing and analysis tools.Current capabilities include phase-picking, filtering, beaming, vespagram creation, spectrogram creation, fk analysis, and spatial coherency analysis. Requirements are MATLAB and its Signal Processing Toolbox, and it can be obtained via the Internet: http://www.ctbt.rnd.doe.gov/ctbt/data/matseis/matseis.html The other is CORAL, a toolbox of about 50 documented MATLAB functions. More information is available at: http://www.geophys.washington.edu/people/faculty/kcc/coral_doc.html A copy may be obtained from anonymous ftp at: ftp://ftp.geophys.washington.edu/pub/out/coral.tar.z Torsten _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: DGentry509@....... Subject: Mt. St. Hellen Seismicity Date: Fri, 7 May 1999 13:24:56 EDT Mount St. Helens Seismicity _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: aaron barzilai Subject: Poster on web Date: Sat, 8 May 1999 11:27:38 -0700 (PDT) Sean-Thomas, i'm still working out the kinks of the setup at larry's, I'm not sure I've recorded anything good yet, though Larry has put a couple of event files up. I attribute it to my lack of field experience. PDF: I can download it fine on both a Mac and a WinNT machine. Are you using Acrobat 3.0? Can you get the circuits? The older posters? Suspension noise: Wha exactly do you mean when you refer to that? Is that the thermomechanical noise associated with teh damping in the 2nd order system? How are you trying to reduce it? Aaron > > Aaron, > > You are probably busy getting ready for the SSA. I was hoping to attend, > but have no funds. But I have been pushing the "earthquake" buttons to > try to get you an event at your setup at Larrys; however, I have found > that a watched seismograph does not quake, at least until you > momentarily disconnect the digitizer or make some fatal adjustment > (There has just been a moderate quake that Giovanni in Italy reports as > a 5+ in the North Atlantic; the STM seis has a nice record, but the > 4.5hz phones are on the bench!). > > I looked at your .../smssl/Geophones/... site and tried to read the > last paper that you have listed there. Unfortunately, ACROBAT had some > problem with the .PDF file. I even had our guru try to fix it, but to > no avail. If you get a chance, maybe you have a version of your current > poster that you can point me to. > > By the way, I have spent some time with a new 4.5 hz phone trying to reduce > the suspension noise, but have not made significant (= repeatable) progress. > At a Tn of 20 seconds, it is about 5 mv p-p, which at 1400V/m/sec, is > about 3.6 microns/second. The microseisms are running about 1 mv p-p. > > So enjoy Seattle. We have a number of people attending, many of whom > are micro-brew fans, so whether you see them or not ....! > > Regards, > Sean-Thomas > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: Poster on web Date: Sat, 08 May 1999 12:48:52 -0700 (MST) On Sat, 8 May 1999, aaron barzilai wrote: > i'm still working out the kinks of the setup at larry's, I'm not sure > I've recorded anything good yet, though Larry has put a couple of > event files up. I attribute it to my lack of field experience. Just wait, we'll get a good sized quake soon enough. It has been fairly quiet lately. > PDF: I can download it fine on both a Mac and a WinNT machine. Are > you using Acrobat 3.0? Can you get the circuits? The older posters? I didn't have any problems downloading the PDF files using Acrobat 3.0.1 John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: kurili Date: Sat, 8 May 1999 22:19:47 +0200 Quake in progress until now. Kurili islands, M 6.6 I.E.S.N. Francesco Nucera
Quake in progress until now.
Kurili islands, M 6.6
 
I.E.S.N.
Francesco Nucera
From: "dave nelson" Subject: Re: Impromptu PSN meeting, etc Date: Sat, 08 May 1999 14:57:26 PDT So it looks like Monday would be best for Dave. Any suggestions as too >where we should meet? If we want to meet around Redwood City we could have >it at Harry's Houfbrau on El Camino Real. If most of the people are coming >from the San Jose area we could have it somewhere down there... >-Larry Cochrane >Redwood City, PSN Larry, i will be arriving at ur place mid-late monday morning. not too much of a drive from Santa Cruz. Dave _______________________________________________________________ Get Free Email and Do More On The Web. Visit http://www.msn.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: The Lahrs Subject: Re: PSN Dinner-Meeting, Golden, Colorado Date: Sat, 08 May 1999 16:57:43 -0600 I've checked with Dave Nelson, and he will be able to come over for a PSN Dinner-Meeting on Friday, May 21. All of the PSN members within (or without, for that matter) striking distance of Denver are welcome. Please let me know ASAP whether or not you will be able to join us. There will be an optional tour of the USGS NEIC in the afternoon for anyone who can make here that early - probably starting at 3 PM. This should be a fun opportunity to meet each other in person and exchange seismo-stories! Cheers, John * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * AOL version of homepage: * * http://lahr.org/john-jan/homepage.html * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Re: Impromptu PSN meeting, etc Date: Sat, 08 May 1999 17:49:28 -0700 --dave nelson wrote: > > So it looks like Monday would be best for Dave. I've lost track of which Monday it is. May 10? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: Impromptu PSN meeting, etc Date: Sat, 08 May 1999 19:17:29 -0700 Doug, Yes its next Monday the 10th. Now all we have to do is decide where and at what time. I think 7:30PM should be OK... -Larry At 05:49 PM 5/8/99 -0700, you wrote: >--dave nelson wrote: >> >> So it looks like Monday would be best for Dave. > > >I've lost track of which Monday it is. May 10? > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: Impromptu PSN meeting, etc Date: Mon, 10 May 1999 00:12:58 -0700 All N. Ca PSNers, Lets meet at Harry's Hofbrau here in Redwood City around 7:30pm. Afterwards people can drop by my house and see my setup. Harry's Hofbrau is at 1909 El Camino Real near Woodside Rd. Their phone number is 650.366.3733. See you there.... -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "James M Hannon" Subject: Re: Poster on web Date: Mon, 10 May 1999 07:21:12 -0500 I can not read the last PDF file listed on the page. The one with the url http://cdr.stanford.edu/DD/SMSSL/Geophones/AGUSpr98PosterFinalCopy.pdf Acrobat reader says the file does not begin with %pdf and indeed it doesn't. Jim Hannon John Hernlund on 05/08/99 02:48:52 PM Please respond to PSN-L Mailing List To: PSN-L Mailing List cc: Subject: Re: Poster on web On Sat, 8 May 1999, aaron barzilai wrote: > i'm still working out the kinks of the setup at larry's, I'm not sure > I've recorded anything good yet, though Larry has put a couple of > event files up. I attribute it to my lack of field experience. Just wait, we'll get a good sized quake soon enough. It has been fairly quiet lately. > PDF: I can download it fine on both a Mac and a WinNT machine. Are > you using Acrobat 3.0? Can you get the circuits? The older posters? I didn't have any problems downloading the PDF files using Acrobat 3.0.1 John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ *************************************************************************** *** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: aaron barzilai Subject: Re: Poster on web Date: Mon, 10 May 1999 12:00:20 -0700 (PDT) Jim, Sorry about that, you are very right. I have corrected it now. By the way, the new address of my website is http://micromachine.stanford.edu/smssl/projects/Geophones/ , Aaron > > > > I can not read the last PDF file listed on the page. The one with the url > http://cdr.stanford.edu/DD/SMSSL/Geophones/AGUSpr98PosterFinalCopy.pdf > Acrobat reader says the file does not begin with %pdf and indeed it > doesn't. > > > Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "James M Hannon" Subject: Re: Poster on web Date: Mon, 10 May 1999 15:12:07 -0500 Aaron, Thanks the PDF reads now. Jim Hannon aaron barzilai on 05/10/99 02:00:20 PM Please respond to PSN-L Mailing List To: psn-l@.............. cc: Subject: Re: Poster on web Jim, Sorry about that, you are very right. I have corrected it now. By the way, the new address of my website is http://micromachine.stanford.edu/smssl/projects/Geophones/ , Aaron _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: PSN Dinner-Meeting, Golden, Colorado Date: Mon, 10 May 1999 22:16:34 -0600 Dave- I hope to be there! -Edward The Lahrs wrote: > I've checked with Dave Nelson, and he will be able to come over > for a PSN Dinner-Meeting on Friday, May 21. All of the PSN members > within (or without, for that matter) striking distance of Denver > are welcome. Please let me know ASAP whether or not you will be > able to join us. > > There will be an optional tour of the USGS NEIC in the afternoon for > anyone who can make here that early - probably starting at 3 PM. > > This should be a fun opportunity to meet each other in person and > exchange seismo-stories! > > Cheers, > John > > * John C. and Jan H. Lahr * > * JohnJan@........ * > * 1925 Foothills Road * > * Golden, Colorado 80401-1718 * > * (303) 215-9913 * > * http://lahr.org/john-jan * > * AOL version of homepage: * > * http://lahr.org/john-jan/homepage.html * > * http://giseis.alaska.edu/lahr * > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rex Klopfenstein, Jr" Subject: VBB Drawings Date: Tue, 11 May 1999 15:00:48 -0400 Sean I have mailed a package of drawings to you today. The package contains two sets of electrical schematics that I have put together from your drawings. I am wondering if you might look at them and see what you think. I want to make sure that I have all the amplifier gains right. Also, check if I have all the filters. I think I am missing the filter that you mentioned in several posts to get rid of a 400 Hz noise. I think this filter is in the displacement transducer circuit. If possible, mark up one set of drawings and return to me in the SASS envelope that I have also enclosed. There is also a parts list for each drawing attached. There is also a listing of a spreadsheet that I have made to calculate the values of the Ri and Rp resistors. I currently using your numbers for the VBB constants. When I get mine built, I can change these values and the spreadsheet will calculate the proper theoretical values of the resistors to match my unit. Thanks in advance Rex Klopfenstein, Jr. Bowling Green, OH _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: VBB Drawings Date: Tue, 11 May 1999 20:13:46 -0700 Rex & Sean Will the schematics be available for others , possible on line or with SSSA? Regards Barry Rex Klopfenstein, Jr wrote: > Sean > > I have mailed a package of drawings to you today. The package contains > two sets of electrical schematics that I have put together from your > drawings. I am wondering if you might look at them and see what you > think. I want to make sure that I have all the amplifier gains right. > Also, check if I have all the filters. I think I am missing the filter > that you mentioned in several posts to get rid of a 400 Hz noise. I > think this filter is in the displacement transducer circuit. > > If possible, mark up one set of drawings and return to me in the SASS > envelope that I have also enclosed. > > There is also a parts list for each drawing attached. > > There is also a listing of a spreadsheet that I have made to calculate > the values of the Ri and Rp resistors. I currently using your numbers > for the VBB constants. When I get mine built, I can change these values > and the spreadsheet will calculate the proper theoretical values of the > resistors to match my unit. > > Thanks in advance > > Rex Klopfenstein, Jr. > Bowling Green, OH > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: The Lahrs Subject: 2nd Spring Colorado PSN Meeting Date: Tue, 11 May 1999 21:25:01 -0600 The 2nd Spring Colorado PSN meeting is taking shape now. Here are the plans: Meet at the USGS Geologic Hazards Team building at 2:50 PM, Friday, May 21. The location is 1711 Illinois Street, Golden, CO. Tour the building. See what Ed's working on and visit the National Earthquake Information Center. Get together in the entry-level lunch area for chips and talk. Bring photos, schematics, seismograms, stories about how the big one got away, etc to share. About 5:30 PM, order some pizza to be delivered. About 7 PM drive to John Lahr's house, which is located about 1 mile to the west at 1925 Foothills Road, for coffee, dessert, a look at John's Lehman-style seismometer, and more talk. At this time we will have in attendance: Dave Nelson and Dave's Denver host(s) Meredith and Lee Ann Lamb John and Jan Lahr Ed Cranswick Raul Alvarez Mark and Elizabeth Meremonte Hope the following can come: Deni Ambrisco Thom DiGeronimo Dewayne and Linda Hill anyone else ?? John * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * AOL version of homepage: * * http://lahr.org/john-jan/homepage.html * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rex Klopfenstein, Jr." Subject: Re: VBB Drawings Date: Wed, 12 May 1999 17:19:51 -0400 I plan on updating the drawings already on my webpage as soon as I get all questions resolved. The first phase will be 'as drawn'. As I assembly and test, I will post revisions. barry lotz wrote: > Rex & Sean > Will the schematics be available for others , possible on line or with > SSSA? > > Regards > Barry > > Rex Klopfenstein, Jr wrote: > > > Sean > > > > I have mailed a package of drawings to you today. The package contains > > two sets of electrical schematics that I have put together from your > > drawings. I am wondering if you might look at them and see what you > > think. I want to make sure that I have all the amplifier gains right. > > Also, check if I have all the filters. I think I am missing the filter > > that you mentioned in several posts to get rid of a 400 Hz noise. I > > think this filter is in the displacement transducer circuit. > > > > If possible, mark up one set of drawings and return to me in the SASS > > envelope that I have also enclosed. > > > > There is also a parts list for each drawing attached. > > > > There is also a listing of a spreadsheet that I have made to calculate > > the values of the Ri and Rp resistors. I currently using your numbers > > for the VBB constants. When I get mine built, I can change these values > > and the spreadsheet will calculate the proper theoretical values of the > > resistors to match my unit. > > > > Thanks in advance > > > > Rex Klopfenstein, Jr. > > Bowling Green, OH > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: 4.5hz-VBB: self noise Date: Wed, 12 May 1999 17:46:07 -0500 (CDT) Aaron, I finally got a look at your posters and papers. They are very nicely done. I wish that I had the time to learn how to produce such good documentation. I assume that the SSA info is the most current, with the latest ideas and designs.. You asked about my concern with suspension noise from the 4.5hz geophone when used as a VBB instrument. As I mentioned previously, the Brownian noise is only one of many noise sources; the circular suspension leaf springs and the fine-wire signal output leads are significant contributors that raise the noise level by as much as 100 to 1000 times the theoretical calculation of the Brownian noise. We have to properly understand the value that is obtained (in both Riedesel and Melton: references below for the curious reader) for the PSD (Power Spectral Density) of the Brownian noise. The equation simply describes the ideal thermal noise imparted to an isolated mass levitated in a standard atmosphere by a suspension that controls the period and where motion is limited by a dissipative damping system. Note that it says nothing about the noise caused by the physical components of the geophone. The mass of a seismometer is always in motion, even under the quietest conditions. This causes the suspension members to flex, and when non-linearities of the suspension forces are of the order of the forces of earth accelerations applied to the mass, noise results. For example, if the microseism background causes an acceleration of one nano-g (10^-9), which is applied to a mass of 0.023kg, (in the 4.5 hz geophone), F=M*A, and a force of 2.3 x 10^-11 Newtons is applied to the suspension. This is very small compared with the force supporting the mass (F=0.023kg*g= 0.225N), but the suspension still has to flex in a linear fashion to produce an undistorted velocity output. But simple suspensions, such as the etched leaf springs of a geophone, are never intended to be linear at these force levels, so micro-bending and warping, along with hysteresis and edge contact effects, result in fairly broadband noise. Obvously, a larger mass will overcome these effects proportionately. This is why very compact but very high quality flexures are used for low noise sensors. A straight flat flexure clearly has a simple and well defined bending pattern compared to the etched spiral leaf spring of a geophone. Its support or contact points are very well constrained, compared to the circularly clamping rings of a geophone. A linear hinge results in linear mass motion, compared to the small rotation caused by the circular leaf spring. THe epitome of compact self-contained rotational flexures are the pricy "Bendix" devices. The other noise source is the fine wire leads for the signal, calibration, and displacement data. In a common geophone, these are fine coils or "pig-tails" run from the moving coil to terminals on the case. In some geophones, the mass, which is usually a brass ring that the coils are wound on, is split by an epoxy ring, and the leaf-spring suspensions at each end carry the signal to insulated shims that anchor the case ends of the springs. I have found that if the coils are long enough so that they touch themselves, the broadband noise is over 20x of when the coils are stretched so that even successive loops don't touch. And having a calibration coil doubles the number of "pig-tails" making noise, but I need one to verify the response, which I have done with the 4.5hz-VBB. In sensors with a capacitive displacement transducer, the lead layout from the moving plate is critical and details are a carefully guarded secret in the commercial sensors. (an advantage of the LVDT or VRDT is that the moving sensing element is passive). I have yet to see a mechanical model of a seismometer or geophone that comes up with actual self-noise figures. For the most part, experiments are the main source of noise determination, often done by side-by-side coherence studies as outlined by Holcomb (reference below) as you have done. As I mentioned previously, I have been evaluating many feedback options for various sensors, including lately a re-visit of the 4.5hz HS-1 to again try to reduce its mechanical self noise. In the data from the Mw 7.1 Monday May 10 in New Britain, P.N.G., the 4-second p-wave was about 4x the noise level at about 20 microns/second, but the 20-second surface waves were less than 2x the noise. A plot of the the PSD of the noise of the sensor shows a relatively flat level of about -130db to -140db from 3 to about 20 seconds where the flat response rolls off; I don't have any higher frequency data. Of course, this is all the mid-day noise of the sensor in the basement 10m from the street, including thermal and barometric noise. However, this level is comparable to your data on instrumental self noise determined by coherence (your SSA figure 11) from 10 seconds to 1 second of a NSD of 10^-7 to 10^-8; where NSD=g/sqrt(hz). (I am unsure how valid the 10^-5 figure (PSD = -80db) at 100 seconds is? It is probably due to the rapidly dropping sensitivity at that period.) For the reader: NSD in g/sqrt(hz) is converted to PSD in m^2/sec^4/hz by substituting 9.8m/sec^2 for g, (effectively multiplying the NSD value by 10), and squaring the result. THe value is usually plotted in db, which is the result x10. So in Aarons' plots of the USGS NLNM (figure 20), the NSD of the 6-second microseism peak is 10^-8; 10x = 10^-7; this squared is 10^-14, the usual PSD figure, which is multiplied by 10 for -140db. Unfortunately, I don't have a multi-channel digitizer here (yet) to do coherence noise studies. I am quite confident that the electronics is not contributing at this level, since I can interchange the 4.5hz phone cable with the STM-8 cable, switch the integrator period and Cf, and the noise is 30 to 40 db less from the 90-second instrument. THe VRDT displacement transducer noise is about 1 nano-meter P-P. It may be possible to further reduce the suspension noise: some modification of the leaf spring clamping rings might better control the contact area. Other problems are with the thermal sensitivity of the mass position (about 4 microns/degree C, dropping with increasing temperature as expected) and suspension resonances within the high-frequency portion of the VBB passband (possibly the unexplained peaks in your data). The mass position change with temperature is a "don't care" for a velocity sensor, but it causes problems with a displacement output of 250 millivolts/micron, even with reasonable VBB loop gains. I use a precision potentiometer to re-balance the sensing bridge over a range of 30 microns (about 600 microns with the feedback on), but this pot adds noise. Regards, Sean-Thomas ______________________ Footnote: A digression for those unfamiliar with the expression: Brownian noise: PSD = (8*pi*k*T)/(M*P*Q) where T is the temperature in Kelvins, M is the mass in kg, P is the period in seconds, and Q is the inverse of the damping (lambda) For example, for the L-4C, M = 1 kg, P = 1 second, and Q is set to 1 ,; T = 300 (room temperature) and k = 1.38*10^-23. Cranking out the numbers gives a PSD for the L4-C of 10^-19. If we substitute the values for the 4.5hz phone, M = 0.023 and P = 0.222, the ratio is 198, so the noise is about 2*10*-17 Some assorted references regarding seismometers and noise: "Limits of Sensitivity of Inertial Seismometers with Velocity Transducers and Electronic Amplifiers"; by Mark A Riedesel, R.D.Moore, and J.A.Orcutt; Bulletin of the Seismological Society of America, Vol. 80, No. 6, December 1990. "The Sensitivity and Dynamic Range of Inertial Seismographs"; by Ben S. Melton; Reviews of Geophysics and Space Physics, Vol 14, No. 1; February 1976; C. American Geophysical Union. "The Design of Miniature Wideband Seismometers" by M.J.Usher, C. Guralp, and R.F. Bursch; Geophysical Journal of the Royal Astronomical Society, vol 55; 1978. "Observations and Modeling of Seismic Background Noise", by Jon Peterson; USGS open file report 93-322, Albuquerque, NM, 1993. A Direct Method for Calculating Instrument Noise Levels in Side-by-Side Seismometer Evaluations", by L. Gary Holcomb, USGS open-file report 89-214, Albuquerque, NM, 1989 A Numerical Study of Some Potential Sources of Error in Side-by-Side Seismometer Evaluations, by L. Gary Holcomb, USGS open-file report #90-preprint, Albuquerque, NM, 1990. Wielandt, E. and G. Streckeisen, "The Leaf-Spring Seismometer: Design and Performance", Bull. Seism. Soc. Am., 72, 2349-2367, December 1982 _______________ PS: sorry if this is too long and technical, but .... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: aaron barzilai Subject: Re: 4.5hz-VBB: self noise^[ Date: Wed, 12 May 1999 17:17:50 -0700 (PDT) Sean-Thomas, Once again, thanks for the note and please give me a couple days to digest. It's quite thorough and I ant to make sure I get it all. Thanks, Aaron _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: Info on your kc1 Date: Fri, 14 May 1999 15:58:55 -0600 Jim- I spent two weeks in San Jose, CA, in April working with Russel Sell and Dave Carver to deploy 40 K2 strong motion seismometers in the neighborhood. Russ told me that he thought you were in contact with the PSN and asked me to send you his regards. Russ was a steadying presence in this door-to-door seismo-salesman campaign, and a great person to work with. -Edward jim E O'Donnell wrote: > Hi Karl, > > By way of introduction I am a retired geophysicist living near Las Vegas > and am interested in your kc1 sensor. > Your 990407a.kc1record is very nice! ML=4.1 @ 78 km's........... > What type of FB did you build? > Also your site seems very quiet... > What is the smallest local Eq., Mag., (say from 10 to 100 km's away) can > you record? Best guess answer... > > I am in the process of converting UNLV's, E-W, 20 year old analog Lehman > to a digital with Larry's boards which are on order, but I want to record > local Eq's and feel a FB is the way to go and will eventually need a > vertical to see Rayleigh waves. > > Appreciate any info you or others can give me, the STM-8 may be the way > to go but looks tough to build. I have a standing offer to the > engineering students at UNLV that I will supply all the pieces and Sean's > schematic, if they want to get some research units and have some fun. No > takers yet! Has any one built a STM-8 yet, besides Sean? I have two > colleagues, both academic types, Tom McEvily, UCB,and Fred Followill, > LLNL, who profess to and marvel at Sean's knowledge and ability in > seismometry. > > Best Regards, > > Jim O'Donnell > 661 Del Prado Dr. > Boulder City, NV 89005 > > 702 293-5664 > jimo17@........ > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: jimo17@........ Subject: Re: K2 deployment Date: Fri, 14 May 1999 19:34:43 -0700 Edward- Glad to hear your keeping Russ busy, Russ and I worked together in 1962-64, when I was a grad student at UCBerkeley. He was always their to bail me out. Could you tell us more about your strong motion program? What's a K2? What are you using for a data logger? I talked to John Anderson, UNRSL, a very good earthquake engineer, and he would like to install strong motion sensors in LV as he thinks we could record small local shakes as well as be ready for the big one. DOE has 30 years of data here, 1963-93, from the Blume Strong Motion Network. We had sensors on every rooftop of buildings, 7 stories and taller, yep over 150, 3 component FBA-11's. This was a DOE Seismic Safety program for the NTS, UNE's, megaton shots = M=6.2, 150 km's from LV. Jim _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Large event at Mammoth Lake Date: Sat, 15 May 1999 06:50:07 -0700 All, Mammoth Lake just had a large event. This is from the Berkeley finger server: 99/05/15 13:22:10 37.53N 118.82W 5.8 5.7Mw B* 19 km SE of Mammoth Lakes, CA -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Ray Gallagher" Subject: Re: Large event at Mammoth Lake Date: Sat, 15 May 1999 06:54:33 -0700 Felt the quake pretty good here in Bakersfield. Ray ----- Original Message ----- From: Larry Cochrane To: Sent: Saturday, May 15, 1999 6:50 AM Subject: Large event at Mammoth Lake > All, > > Mammoth Lake just had a large event. This is from the Berkeley finger server: > > 99/05/15 13:22:10 37.53N 118.82W 5.8 5.7Mw B* 19 km SE of Mammoth > Lakes, CA > > -Larry Cochrane > Redwood City, PSN > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Norman Davis WB6SHI Subject: Re: Large event at Mammoth Lake Date: Sat, 15 May 1999 06:56:08 -0700 Felt it hear in Shingle Springs and a ratteler At 06:50 AM 5/15/99 -0700, you wrote: >All, > >Mammoth Lake just had a large event. This is from the Berkeley finger server: > >99/05/15 13:22:10 37.53N 118.82W 5.8 5.7Mw B* 19 km SE of Mammoth >Lakes, CA > >-Larry Cochrane >Redwood City, PSN > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > Norman M. Davis WB6SHI Shingle springs, CA mailto:normd@............. http://www.directcon.net/normd/index.htm ICQ: 7192318 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: Large event at Mammoth Lake Date: Sat, 15 May 1999 07:52:17 -0700 Now that was interesting :) I'll upload 4 slightly cliped events Barry Larry Cochrane wrote: > All, > > Mammoth Lake just had a large event. This is from the Berkeley finger server: > > 99/05/15 13:22:10 37.53N 118.82W 5.8 5.7Mw B* 19 km SE of Mammoth > Lakes, CA > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: aaron barzilai Subject: Re: 4.5hz-VBB: self noise Date: Sat, 15 May 1999 09:25:02 -0700 (PDT) Sean-Thomas and everyone, I got a chance to respond to your earlier email Sean-Thomas. I hope it answers some of your questions. I have a few for you, too. I included from your orginal email the sections I respond to. Enjoy! Thanks, Aaron -------------------------------------------------------------------------- > > > Aaron, > > I finally got a look at your posters and papers. They are very nicely > done. I wish that I had the time to learn how to produce such good > documentation. I assume that the SSA info is the most current, with the > latest ideas and designs.. Thanks, I think good documentation is pretty important. I would say it's not so hard to do, with the right tools. Indeed, the SSA'99 info is the most current. > > > You asked about my concern with suspension noise from the 4.5hz > geophone when used as a VBB instrument. As I mentioned previously, > the Brownian noise is only one of many noise sources; the circular > suspension leaf springs and the fine-wire signal output leads are > significant contributors that raise the noise level by as much as > 100 to 1000 times the theoretical calculation of the Brownian noise. > In what frequency range? > We have to properly understand the value that is obtained (in both > Riedesel and Melton: references below for the curious reader) for > the PSD (Power Spectral Density) of the Brownian noise. The equation > simply describes the ideal thermal noise imparted to an isolated mass > levitated in a standard atmosphere by a suspension that controls the > period and where motion is limited by a dissipative damping system. > Another note for the reader. This thermal noise is purely the result of the dissipation. If there were no damping, there would be no thermal noise > This is very small compared with the force > supporting the mass (F=0.023kg*g= 0.225N), but the suspension still > has to flex in a linear fashion to produce an undistorted velocity > output. But simple suspensions, such as the etched leaf springs of a > geophone, are never intended to be linear at these force levels, so > micro-bending and warping, along with hysteresis and edge contact effects, > result in fairly broadband noise. Obvously, a larger mass will overcome > these effects proportionately. . . . > I have yet to see a mechanical model of a seismometer or geophone that > comes up with actual self-noise figures. For the most part, experiments > are the main source of noise determination, often done by side-by-side > coherence studies as outlined by Holcomb (reference below) as you have > done. . . . > As I mentioned previously, I have been evaluating many feedback options > for various sensors, including lately a re-visit of the 4.5hz HS-1 to again > try to reduce its mechanical self noise. In the data from the Mw 7.1 Monday > May 10 in New Britain, P.N.G., the 4-second p-wave was about 4x the noise > level at about 20 microns/second, but the 20-second surface waves were less > than 2x the noise. A plot of the the PSD of the noise of the sensor shows a > relatively flat level of about -130db to -140db from 3 to about 20 seconds > where the flat response rolls off; I don't have any higher frequency data. > Of course, this is all the mid-day noise of the sensor in the basement > 10m from the street, including thermal and barometric noise. However, this > level is comparable to your data on instrumental self noise determined > by coherence (your SSA figure 11) from 10 seconds to 1 second of a NSD > of 10^-7 to 10^-8; where NSD=g/sqrt(hz). (I am unsure how valid the > 10^-5 figure (PSD = -80db) at 100 seconds is? It is probably due to the > rapidly dropping sensitivity at that period.) I'm not so sure I agree with your statements in this section, particularly about how the sensors won't work well with small displacements. Of course, I have much less experience in this field than you do. But, as you pointed out, I have measured the instrumental noise of a geophone(4.5 Hz GS-11D in what you called Figure 11, but I think you mean page of 11 of my SSA'99 poster). In case it wasn't clear, I want to emphasize that the thick red line on page 11 is a prediction based on thermal noise, op-amp voltage and current noise, etc. This prediction is teh value at 100 sec S-T mentions. The thin black line is measured data and goes to periods as long as 10 seconds, but not out to 100 sec. This measurement was done using a side-by-side coherence technique, as the measured outputs were about 2 orders of magnitude above the instrumental noise plotted. It is important to note that the dominant effects are the op-amp(an OP-470 in this case) noise. You say "I have yet to see a mechanical model that comes up with actual self-noise figures." I think you are trying to say, "I've never seen anyone measure the noise of a seismometer and find they see the predicited thermal noise." Clearly, I have not done that either, but I have a model(not sure what you mean by mechanical), it does produce predictions of self-noise, and they have been validated experimentally. So I think what I(and others) have done meets your stated requirements, but not what you were driving at. Is this correct? I will point out that at the resonance, I have measured the noise to be within a factor of 2(roughly) of the predicted thermal noise, so I don't see 100 to 1000 times increase there. I can't make many comments about what's happening at 10 seconds, because you can't really look at it with conventional geophones. With my capacitive geophones, I see at most 50 ng/rootHz noise there. I believe this is limited by my instrumentation, and hope to take some better data this week. So I hope to have data illustrating that the noise is about 1 ng/rootHz there in a week or so. This would still be about a factor of 5 over thermal noise, but again I believe it will be limited by op-amp noise, not excess motion. > > Unfortunately, I don't have a multi-channel digitizer here (yet) to do > coherence noise studies. I am quite confident that the electronics is not > contributing at this level, since I can interchange the 4.5hz phone > cable with the STM-8 cable, switch the integrator period and Cf, and > the noise is 30 to 40 db less from the 90-second instrument. THe VRDT > displacement transducer noise is about 1 nano-meter P-P. > If you're not doing a coherence measurement, aren't you just seeing the ambient seismic signal, not the instrumental noise? Are you locking the mass or something? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: New event Date: Sat, 15 May 1999 11:01:45 -0700 Another one coming in @ ~ 17:56:00 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: meredith lamb Subject: Busy day in California.... Date: Sat, 15 May 1999 12:11:03 -0600 Barry, Just got your msg and noted one just coming in, about 19:00 UT. Location? See Larry is busying making event files ....... busy, busy, busy. Ha. Good day to stay home and check the "graph". Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: Busy day in California.... Date: Sat, 15 May 1999 11:24:36 -0700 Meredith It looks like a 5.3 @ 17:54:08 UTC @ Mammoth again. I got three more event files but I'll hold off posting so as to not load up the list regards Barry meredith lamb wrote: > Barry, > > Just got your msg and noted one just coming in, about 19:00 > UT. Location? > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Steve Hammond Subject: Re: Busy day in California.... Date: Sat, 15 May 1999 20:40:39 -0700 Hi Barry, boy-- I don't know about you, but I'm gettung some really great records from Tom's Place here in the bay area. I moved to Campbell, CA, 6m west of the old Falon Station in San Jose, last October and this is the first major series I've recorded at this location. I'm on deeper bay area sedimentary formations then I was and I was not too sure what to expect in the way of recording quality. I'm just running the HS10 geophones at this point and that last event at 17:54:08 was well on-scale and my clock was only about .05 seconds off so I was able to pin it at 302km from here. I also recorded two more around 13:25 and it looks like 4.0 is about the max I'll trigger on at that distance. The odd part is Stephanie's dogs are also here and the German Shepard must be hearing something because he has wacked-out a few times last night and today. Did you look at Berkley/USGS WEB site. Tome's place - Mammoth Lakes is really rock'en. >50 events in the last few hours. Regards, Steve Hammond PSN San Jose, CA barry lotz wrote: > > Meredith > It looks like a 5.3 @ 17:54:08 UTC @ Mammoth again. I got three more > event files but I'll hold off posting so as to not load up the list > regards > Barry > > meredith lamb wrote: > > > Barry, > > > > Just got your msg and noted one just coming in, about 19:00 > > UT. Location? > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: Busy day in California.... Date: Sat, 15 May 1999 14:03:10 -0700 Hi Steve It is good to have a check on ones experiments. I wish I had some rail to rail, dual opamps right now. I could get a little more amplitude. I also wish I had a color monitor so I could run SDR. Emon is great but I have a 4.5 geophone and I would like to run the same sensor at different frequency filtering. Larrys A/D board will take six inputs which would do. To all- What might be a good dual, low power, precision, rail to rail opamp? I am thinking of using MAX407's. Karl - the FB seems to work at this distance. Regards Barry Steve Hammond wrote: > Hi Barry, boy-- I don't know about you, but I'm gettung some really > great records from Tom's Place here in the bay area. I moved to > Campbell, CA, 6m west of the old Falon Station in San Jose, last October > and this is the first major series I've recorded at this location. I'm > on deeper bay area sedimentary formations then I was and I was not too > sure what to expect in the way of recording quality. I'm just running > the HS10 geophones at this point and that last event at 17:54:08 was > well on-scale and my clock was only about .05 seconds off so I was able > to pin it at 302km from here. I also recorded two more around 13:25 and > it looks like 4.0 is about the max I'll trigger on at that distance. The > odd part is Stephanie's dogs are also here and the German Shepard must > be hearing something because he has wacked-out a few times last night > and today. > > Did you look at Berkley/USGS WEB site. Tome's place - Mammoth Lakes is > really rock'en. >50 events in the last few hours. > > Regards, Steve Hammond PSN San Jose, CA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: The Lahrs Subject: PSN/CoPEPP Meeting - May 21, 1999 Date: Sun, 16 May 1999 07:54:58 -0600 PSN/CoPEPP Meeting - May 21, 1999 Plans are shaping up for the meeting of the PSN, with, I hope, some participants of the Colorado Princeton Earth Physics Project (CoPEPP). The meeting will begin at 3 PM with a tour of the USGS facilities, including the NEIC earthquake operations area, conducted by Waverly Person, and continuing with John McMillan showing us the electronics area and some interesting seismic instruments. We will then spend some time getting to know each other in the entry level meeting room. I'll set up a few of my hands-on seismic-education demonstrations there. When hunger strikes, we'll send out for some pizza. At around 7 pm or so we'll make the short drive over to my house to see my fledgling seismic system and have some coffee and dessert. I put a map here http://lahr.org/john-jan/psn/gldn_psn.html that shows where the USGS (1711 Illinois St.) and my house (1925 Foothills Rd.) are located. Parking: Park behind the building (on the east side) either in the USGS lot right next to the USGS building or in the lower lot a bit farther east. If you come after 4 PM the doors will be locked. I'll rig up a door bell so that you will be able to get someone's attention to get in. Anyone with an interest in seismology and seismology education is welcome to attend. Please send me an Email (john@......... if you plan to do so. * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * AOL version of homepage: * * http://lahr.org/john-jan/homepage.html * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: The Lahrs Subject: map correction: PSN Meeting Date: Sun, 16 May 1999 08:18:09 -0600 I gave the wrong URL for the map to the USGS. It is: http://lahr.org/john-jan/psn/usgsmap.jpg and the USGS is on the corner of Illinois and 18th street. John * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * AOL version of homepage: * * http://lahr.org/john-jan/homepage.html * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "dave nelson" Subject: Re: PSN/CoPEPP Meeting - May 21, 1999 Date: Sun, 16 May 1999 07:10:09 PDT John, thanks for ur wonderful efforts. so looking forward to meeting u all. my host terry wilkinson is a definate starter for the tour etc and his partner debbie is keen too. i said there were to be anopther couple of lady's there so she wouldnt feel out of place. I leave LA this morning sunday 16th may 10am, by bus getting to denver monday morning similar time. take care all see ya soon. Dave _______________________________________________________________ Get Free Email and Do More On The Web. Visit http://www.msn.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Bob Fryer Subject: Menlo Park to Mammoth?? Date: Mon, 17 May 1999 00:45:39 -0700 Hi gang, Can someone suggest the best route from Menlo Park to Mammoth Lakes, for this time of year? Thanks much, Bob F -- Beaverton, OR ----- earthquake WARNING research ----- --- animals, people, scientific evidence --- --- http://www.teleport.com/~bfryer --- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Steve Hammond Subject: Re: Menlo Park to Mammoth?? Date: Mon, 17 May 1999 08:34:20 -0700 Check with the CHP to see if 50 is open to Tahoe and head south on 89/395 to Mono and then John's Place. You will want to make a reservation in Mammoth if you are going to stay overnight in that area. When it is open, 4 from Angels Camp to Markleeville is a great way to see the very top of the range. But give yourself lots of time if you take that road because you will want to stop and look around. Regards, Steve Hammond PSN San Jose. Bob Fryer wrote: > > Hi gang, > > Can someone suggest the best route from Menlo Park to Mammoth Lakes, for > this time of year? > > Thanks much, > Bob F -- Beaverton, OR > > ----- earthquake WARNING research ----- > --- animals, people, scientific evidence --- > --- http://www.teleport.com/~bfryer --- > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: wizard@......... (Rick Jerome) Subject: Re: Menlo Park to Mammoth?? Date: Mon, 17 May 1999 06:24:46 -0700 Sonora Pass opened this weekend. When I lived in the Bay area and Tioga Pass was closed Sonora Pass was the best route. Take the highway to Manteca cutoff. Head towards Manteca and take the highway 108/120 exit, (Sonora). Stay on highway 108 through Sonora and continue east over Sonora Pass to Bridgeport. Take highway 395 South to Mammoth. TAKE TIRE CHAINS!.. Have a nice trip. -----Original Message----- From: Bob Fryer To: PSN-L Mailing List Date: Monday, May 17, 1999 1:03 AM Subject: Menlo Park to Mammoth?? > >Hi gang, > >Can someone suggest the best route from Menlo Park to Mammoth Lakes, for >this time of year? > >Thanks much, >Bob F -- Beaverton, OR > >----- earthquake WARNING research ----- >--- animals, people, scientific evidence --- >--- http://www.teleport.com/~bfryer --- > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Tom Lambert Subject: DIRECTIONS Date: Mon, 17 May 1999 10:10:08 -0500 GREAT DIRECTIONS STEVE! Steve Hammond wrote: > Check with the CHP to see if 50 is open to Tahoe and head south on > 89/395 to Mono and then John's Place. You will want to make a > reservation in Mammoth if you are going to stay overnight in that area. > When it is open, 4 from Angels Camp to Markleeville is a great way to > see the very top of the range. But give yourself lots of time if you > take that road because you will want to stop and look around. > > Regards, Steve Hammond PSN San Jose. > > Bob Fryer wrote: > > > > Hi gang, > > > > Can someone suggest the best route from Menlo Park to Mammoth Lakes, for > > this time of year? > > > > Thanks much, > > Bob F -- Beaverton, OR > > > > ----- earthquake WARNING research ----- > > --- animals, people, scientific evidence --- > > --- http://www.teleport.com/~bfryer --- > > > > _____________________________________________________________________ > > > > Public Seismic Network Mailing List (PSN-L) > > > > To leave this list email listserver@.............. with the body of the > > message: leave PSN-L > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: [Fwd: Induced seismicity [Fwd: White Pine flooding]] Date: Mon, 17 May 1999 13:48:25 -0600 Wayne- I guess that until something starts shaking at a perceptible level we would not have the resources available to address the issue. Tony Crone and Randy Updike are the Assistant CS and Chief Scientist respectively of the Central Geohazards Team and are in charge of the USGS response to seismic hazards in Central & Eastern US. I have also forwarded your email to several other people such as Nano at Lamont. Perhaps if something begins to happen, some local talent such as the Public Seismic Network might be interested in monitoring . -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". Hi Ed, I briefly discussed Wayne Pennington's request with Randy, and as I surmised, we don't see any obvious way that we can unilaterally support this proposed monitoring effort. You know as well as anyone, that we don't have surplus instruments available to deploy for this monitoring, especially considering that this entire process could encompass many months to years. Secondly, we don't have the luxury of having extra staff members and resources that we can allocate to establish the deployment, assure that the instruments are collecting and transmitting data properly, and coordinating with local scientists to continue operations (under some seasonally tough conditions). If there is an onset of seismic activity, we would certainly want to discuss the possibility of a short-term deployment, depending on the size of the events and the logistic complexities of a temporary deployment (including the season of the year). As you well know, many factors go into deciding whether to deploy stations in response to seismic activity, and we'd have to consider and discuss these factors as part of the decision-making process. In short, it does not seem likely that we've got the resources or staff to install stations in advance of any notable seismicity, but if some induced seismicity does occur, we would consider responding, depending on many variables. Tony =============================================== > Tue, 11 May 1999 17:54:44 -0400 (EDT) >From: "Wayne D. Pennington" >Received: (from wayne@localhost) > by dimspot.geo.mtu.edu (8.8.8/8.8.8/mtuclient-1.0) id RAA03910; > Tue, 11 May 1999 17:54:45 -0400 (EDT) >Date: Tue, 11 May 1999 17:54:45 -0400 (EDT) >Message-Id: <199905112154.RAA03910@...................> >To: "Edward Cranswick, Lakewood, CO " >Subject: White Pine flooding >Cc: "David B Westjohn, Hydrologist, Lansing, MI >" > >(a note to Ed Cranswick of USGS, Golden CO, with cc: to >David Westjohn, USGS, Lansing MI, with some details missing >from my phone message to Ed. Dave: I knew Ed back in our >mutual days at Lamont... time flies, but it's still a small world)) > >Hi Ed: > >The White Pine copper mine is an underground room-and-pillar mine >that has excavated 13 square miles of rock, averaging 20 ft high, >from an area covering 24 square miles, along a plane starting at >the surface and extending to a depth of 2800 ft. It is huge. >And it is now filling with a very nasty formation brine, which may >ultimately leak into nearby Lake Superior. In an effort to halt >the rise of brine, the owners have proposed filling the mine with >fresh water very quickly, resulting in a natural stratification that >will keep the brine down deep in the mine for a couple of centuries. > >This filling is proposed to start soon (summer?); the people involved >had not thought of the likelihood of induced seismicity, but >immediately recognized the problem once it was brought to their >attention (by me a couple of weeks ago, talking with David Westjohn). >The state would now like to see that some monitoring takes place, >and would like Copper Range (the company abandoning the mine) pay >for at least a significant fraction of the study. We are looking >for two things -- equipment and time. We may or may not get much >money from Copper Range or the state to do the job right, but would >like to have as inexpensive a proposal as practical to present to >them. The induced seismicity could be a concern, of course, for >the shaking it produces; but it also could indicate fracturing >toward Lake Superior (only a few hundred yards from the surface >opening of the mine), which would be a no-no. Lake Superior is >seriously protected, and spilling heavy metals into it is a big >problem. We are also concerned about the possibility of seiches >within the (huge) mine caused by seismic activity or collapses. > >(By the way, White Pine has had a couple of major collapses in the >past, and some large underground explosions were used by Los Alamos >to study contained chemical detonations for comparison with nuclear >blasts, etc...) > >White Pine is about a two-hour drive from Houghton, where I currently >work at Michigan Technological University. Terrain is moderate >topography; line-of-sight for telemetry would be feasible. A central >station could have electricity and phone lines, easily. Access to >remote sites by jeep and snowmobile. Winters here are really tough -- >expect 10 feet of snow on the ground, so any telemetry will have to >take that into account. Should be easy and fun to establish a 5- or >6-station network; we live in a wilderness here, and bears are a major >road hazard. > >So... we wonder if the USGS has either or both: >1) equipment: at least one station with MEQ's ready to deploy if >activity spotted; preferably several stations in an array. We may or >may not have much activity, but I'm betting it will be active. >2) personnel: of course, I could manage quite a bit of the operation, >but I'm real busy and I would cost real dollars. We are hoping that >the USGS has some contingency support to provide their own personnel >when the cause warrants it. There are many variations on this theme -- >the USGS could install and initially operate the network, then turn >over daily operations and maintenance to us, with continued oversight >and involvement; they could mail us equipment and manuals, and wish >us luck; they could do the whole thing, and I'd watch from the sidelines; >and so on. I'd love to participate; my real interest is always induced >seismicity, even when I'm working on oil and gas exploration.... > >Well, maybe that's enough introduction.. enough to permit you to >ask around the office and see what can be done. Any other details, >just call or e-mail. Good to hear from you again! > >wayne >++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >Wayne D. Pennington e-mail: wayne@....... >Dept of Geological Engineering and Sciences phone: (906) 487-3573 >Michigan Technological University fax: (906) 487-3371 >1400 Townsend Drive; Houghton, MI 49931 USA >+++++++++++++++++++++++++++++++++++++++in the beautiful Upper Peninsula+ ************************************ Anthony J. Crone Geologic Hazards Team Research Geologist U.S. Geological Survey MS 966, Box 25046 Denver, Colorado 80225-0046 U.S.A. ------------------------------------ /\ phone: (303) 273-8591 /\ /\/^^\/\ FAX: (303) 273-8600 /^^\/ /^^^/^^\/\ e-mail: crone@................... / / /^^^/^^^/ \ ************************************* From: aaron barzilai Subject: Re: Busy day in California.... Date: Mon, 17 May 1999 13:26:29 -0700 (PDT) I use OP-270's. A little pricey, but they work great. Aaron _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ken Navarre Subject: Re: Busy day in California.... Date: Mon, 17 May 1999 14:26:09 -0700 (PDT) On Sat, 15 May 1999, Steve Hammond wrote: [snip] > it looks like 4.0 is about the max I'll trigger on at that distance. The > odd part is Stephanie's dogs are also here and the German Shepard must > be hearing something because he has wacked-out a few times last night > and today. I wasn't going to mention this because... well, you know... We got another new puppy a few weeks ago. Every morning its my task to let him out and reward him for going potty.. Just before the 6.0 event I let him out early because he was going nuts in his kennel. Barking, crying, and banging around. When I let him out he wasn't interested in going potty. Kind'a unusual since he hadn't gone all night and hadn't wet his kennel. When he went outside he laid down on the grass and began crying and pawing at his ears. I was really concerned that he may have gotten a foxtail in his ear. then... I heard the alarm go off from the USGS telemetry from Mt. Hamilton. A few seconds later the puppy was fine. No more concern. No more pawing at his ears... I went inside and watched the telemetry bounce around and my LC-4 saturate for the next 45 seconds... Back in the 70's I participated in a project with SRI to evaluate animal responses before and during earthquakes. Never did see anything like what we saw before the Mammoth 6.0 on saturday morning. Started me thinking... It was really wierd! Ken _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ted Blank Subject: Cheap air fares to Denver? Date: Mon, 17 May 1999 15:37:13 -0700 (PDT) My son and I would love to come to the Denver meeting but the airlines are not cooperating with my pricing proposals...anyone know of a cheap source for tickets? We could fly from San Jose, SFO or Oakland. I've tried the web sites but they are still about $500 each r/t. Ted Blank San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: Busy day in California.... Date: Mon, 17 May 1999 16:03:54 -0700 (MST) On Mon, 17 May 1999, Ken Navarre wrote: > On Sat, 15 May 1999, Steve Hammond wrote: > > it looks like 4.0 is about the max I'll trigger on at that distance. The > > odd part is Stephanie's dogs are also here and the German Shepard must > > be hearing something because he has wacked-out a few times last night > > and today. > I wasn't going to mention this because... well, you know... > We got another new puppy a few weeks ago. Every morning its my task to > let him out and reward him for going potty.. Just before the 6.0 event I > let him out early because he was going nuts in his kennel. Barking, > crying, and banging around. When I let him out he wasn't interested in > going potty. Kind'a unusual since he hadn't gone all night and hadn't > wet his kennel. > When he went outside he laid down on the grass and began crying and > pawing at his ears. I was really concerned that he may have gotten a > foxtail in his ear. then... I heard the alarm go off from the USGS > telemetry from Mt. Hamilton. A few seconds later the puppy was fine. No > more concern. No more pawing at his ears... This is a great story Ken! How long before the P-wave arrival was he behaving in this manner? John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: more 4.5hz-VBB self noise Date: Mon, 17 May 1999 20:09:03 -0500 (CDT) Aaron, Thanks for your comments. The 6.0 and aftershocks in the CA/NV border region should have given everyone some nice data. THe S-TM here, recording on the drum, shows a very nicely dispersed surface wave with periods starting at about 40 seconds. THe later 7.0 at P.N.G. showed several hours of surface waves. The experimental VBB geophone showed the 20-second surface waves, but only at about 4x the noise of 3,5 microns/second. The concurrent pre-event microseisms from the 90-second S-TM were running about 0.24 microns/second, showing clean sine waves with the noise below the least count of my digitizer of 0.1 millivolt, which at 4200 V/m/sec, is about 24 nanometers/second. I do not think that a VBB instrument is worth considering unless it clearly shows the 6-second microseism background. Regarding the mechanical self noise question of the small geophone. As I mentioned, this is the essentially broadband noise, of interest here in the range from 100 seconds to 100 hz, that is caused by the earths' background noise, mostly the 6-second microseisms, (but also from random motion caused by the Brownian thermal noise), moving the suspension and wiring components of the seismometer and causing non-linear motion of the mechanical suspensions. If we dunked the seis in liquid helium to kill the thermal noise, or evacuated it, and/or made a quartz fiber suspension so the Q would be 1000 (damping = zilch), this noise would still be present. The great art of sensor design has focussed on how to allow the mass to move within the frame without the springs, hinges, and wires producing nonlinear forces that are position dependent. Successful designs are very simple, with minimal surface contacts, relatively small hinges or flexures, etc, all of which make them quite fragile. A geophone, however, is mostly the opposite, with the design focussed on robustness and high intrinsic damping (of .3 to .6) that limits the mass excursions in handling. As you have shown in your figure on page 11 of your SSA poster paper, when the noise of an instrument is plotted, it is corrected for the output sensitivity of the sensor at each frequency or period. THis means that if the noise level is constant across the frequencies of interest, and is divided by a strongly peaked response of a sensor, the noise curve will look like the inverse of the instrument sensitivity, with a minimum where the sensor has the highest output. This narrow-band response is optimized around the mechanical period To of the sensor, and is usually smooth and symmetrical with critical damping. The output is even greater with an underdamped response, or resonant as you call it, ("resonance" is sort of a "dirty word" in this business, since an undamped instrument response makes the response to seismic waves "ringy" and useless for analysis). Under such narrow-band conditions, the relative level of the output noise will be at a minimum at To. But we are particularly interested in obtaining a broadband response from a fedback sensor equipped with a displacement detector, where the sensor output is constant over a wide frequency or period range. THe relative broadband output level can be estimated from the response of the basic non-fedback sensor by drawing a line between the levels at the high and low frequency corners of the expected flat response. In your page 9 graph of "total sensitivity", the graph shows that the output level at about 8 seconds and at 100 hz is about 60 V/g. A line between these two points would be the broadband sensitivity, and does agree with the flat acceleration response you show on page 18. This level is down by a factor of 35 from 2100 V/g at the peak response. If this level is used in place of the peaked narrow-band response to determine the noise level of page 11, the broadband noise will be about 35 times higher (in g/sqrt(hz) at all frequencies. So instead of the narrow-band value of 10^-9 g/sqrt(hz), (PSD = -160db), it will be 3.5 x 10^-8, or a PSD of -129db. This is similar to the value you show on page 20 for the capacitive geophone. It is also about what I see from the VRDT geophone, at about -130db, about 10x the level of the summer mid-continent microseisms of -140db. This difference between -160db and -129db in PSD, which is the preferred way of expressing such signal levels, is the factor of about 1000 times more noise that I had referred to previously. So thermal noise and mechanical noise are not the same, and while a theoretical number can be placed on the Brownian thermal noise, only experimentation can characterize the mechanical noise caused by micropositioning of the moving elements of a seismometer. By the way, I have a problem with the flat velocity response shown on page 19; if the velocity data is obtained by direct integration of a flat acceleration response, shouldn't it have a slope of 1/omega? Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: aaron barzilai Subject: Re: more 4.5hz-VBB self noise Date: Mon, 17 May 1999 18:19:11 -0700 (PDT) I wanted to answer one of your points quickly. There's both a velocity and and acceleration output- note the block diagram. The acceleration is integrated and then output, thus, it is flat to velocity. I'll take a look at the rest of your mail in the next couple of days, as I gotta run. Aaron _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: Cheap air fares to Denver? Date: Mon, 17 May 1999 18:30:02 -0700 Ted, I was thinking the same thing but $500.00 for a one day trip is a bit too much.... -Larry Cochrane Redwood City, PSN At 03:37 PM 5/17/99 -0700, you wrote: >My son and I would love to come to the Denver meeting but the airlines >are not cooperating with my pricing proposals...anyone know of a cheap >source for tickets? We could fly from San Jose, SFO or Oakland. I've >tried the web sites but they are still about $500 each r/t. > > >Ted Blank >San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Stephen Caruso" Subject: Re: Busy day in California.... Date: Mon, 17 May 1999 22:44:27 -0400 Well my cat has been a little unsettled lately.... maybe the Storm coming tonight Stephen Caruso Cols., OH ----- Original Message ----- From: Ken Navarre To: PSN-L Mailing List Sent: Monday, May 17, 1999 5:26 PM Subject: Re: Busy day in California.... > > On Sat, 15 May 1999, Steve Hammond wrote: > [snip] > > it looks like 4.0 is about the max I'll trigger on at that distance. The > > odd part is Stephanie's dogs are also here and the German Shepard must > > be hearing something because he has wacked-out a few times last night > > and today. > > I wasn't going to mention this because... well, you know... > We got another new puppy a few weeks ago. Every morning its my task to > let him out and reward him for going potty.. Just before the 6.0 event I > let him out early because he was going nuts in his kennel. Barking, > crying, and banging around. When I let him out he wasn't interested in > going potty. Kind'a unusual since he hadn't gone all night and hadn't > wet his kennel. > > When he went outside he laid down on the grass and began crying and > pawing at his ears. I was really concerned that he may have gotten a > foxtail in his ear. then... I heard the alarm go off from the USGS > telemetry from Mt. Hamilton. A few seconds later the puppy was fine. No > more concern. No more pawing at his ears... > > I went inside and watched the telemetry bounce around and my LC-4 > saturate for the next 45 seconds... > Back in the 70's I participated in a project with SRI to evaluate animal > responses before and during earthquakes. Never did see anything like > what we saw before the Mammoth 6.0 on saturday morning. Started me > thinking... It was really wierd! > > Ken > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: DGentry509@....... Subject: Re: Cheap air fares to Denver? Date: Mon, 17 May 1999 22:54:48 EDT Try www.iflyswa.com Southwest Airlines. Not sure they go to Denver but Seattle-San Jose-Salty lake City-Seattle with Wenatchee r/t thrown in was less than $600. This is walk up and buy and refundable tickets for one. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: Re: more 4.5hz-VBB self noise Date: Mon, 17 May 1999 23:27:10 -0500 (CDT) Aaron, You say that "the acceleration is integrated, and then output, thus it is flat to velocity". I am looking at the schematic of page 16 and the block diagram of page 17, both of which show an integrator with acceleration as input and velocity as output. As I said, IF the input is a flat response to acceleration, as shown on page 18 with units of Volts/g, the output, with units of Volts/m/sec as shown on page 19, should have a slope of omega. However, IF the velocity response is indeed flat, then the acceleration response must have a slope of 1/omega. Am I missing something? Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "J. D. Cooley" Subject: Re: Cheap air fares to Denver? Date: Tue, 18 May 1999 05:31:55 -0700 At 03:37 PM 5/17/99 -0700, Ted Blank wrote: >My son and I would love to come to the Denver meeting but the airlines >are not cooperating with my pricing proposals...anyone know of a cheap >source for tickets? We could fly from San Jose, SFO or Oakland. I've >tried the web sites but they are still about $500 each r/t. > > >Ted Blank >San Jose, California Try http://www.bestfares.com/ "JD" Always do right. This will gratify some people and astonish the rest. Mark Twain _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: ralvarez@........ (Raul Alvarez) Subject: Re: Cheap air fares to Denver? Date: Tue, 18 May 1999 07:10:30 -0600 (MDT) Hi Ted, try Frontier Air 1-800-432-1359 They fly LA to Denver. Raul >My son and I would love to come to the Denver meeting but the airlines >are not cooperating with my pricing proposals...anyone know of a cheap >source for tickets? We could fly from San Jose, SFO or Oakland. I've >tried the web sites but they are still about $500 each r/t. > > >Ted Blank >San Jose, California > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ "My dreams are the seeds of my reality, nurtured in the womb of my soul" RJA, 1985 Raul J. Alvarez La Estrellita Observatory Bellvue, Colorado, USA e-mail ralvarez@........ homepage www.frii.com/~ralvarez "The Renaissance Experimenter" doing research in: Radio and Optical Astronomy, Seismology, Weather, Computers, Instrumentation and Neat Stuff! ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ken Navarre Subject: Re: Busy day in California.... Date: Tue, 18 May 1999 08:59:03 -0700 (PDT) On Mon, 17 May 1999, John Hernlund asked: Regarding Ken's puppy story... > This is a great story Ken! How long before the P-wave arrival was he behaving > in this manner? He was making enough noise to wake us up early. Once I let him out it was about 30 seconds of massive ear rubbing and whinning before the Pwave triggers sounded. I'd guess that it was a good 5 minutes of being annoying before I got up and investigated why he was being so pushy to go out. I assumed that he was just ready to go potty and had to go really bad. Like, when we're trapped in stopped commute traffic and have consumed 4 cups of coffee, 2 sodas, and a bag of Fritos before our trip... and REALLY have to find a gas station. Legs crossed, whinning... I know exactly what he was going through. The only problem was that once he was let out he wasn't interested in potty, cookies, or attention. He just laid on the grass and whined and pawed at this ears. After the PWave alarm sounded he stopped... then, he peed. I dunno... It was certainly interesting. We're heading over to the Eastern Sierras tomorrow. We were planning to go to Lone Pine for a few days but may divert to Tom's Place to test his (ummm) ability... There's a few nice camp locations near ground zero... Bobbie (my S.O.) has never been right on top of the focus when the rock broke. I'd like for her to experience the wonder of that huge BANG. I had the pleasure during the Big Bear earthquake sequence a few years back. It was awesome! If I have cell phone access from the location I'll log on and let the group know what's shaking... I'll try to pack up my LC-4 and portible unit. There's several telemetry sites that I can access with Larry's demod unit and SDR. Ken _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: aaron barzilai Subject: Re: more 4.5hz-VBB self noise Date: Tue, 18 May 1999 10:06:45 -0700 (PDT) > > Aaron, > You say that "the acceleration is integrated, and then output, > thus it is flat to velocity". > > I am looking at the schematic of page 16 and the block diagram of > page 17, both of which show an integrator with acceleration as input > and velocity as output. As I said, IF the input is a flat response to > acceleration, as shown on page 18 with units of Volts/g, the output, > with units of Volts/m/sec as shown on page 19, should have a slope > of omega. However, IF the velocity response is indeed flat, then the > acceleration response must have a slope of 1/omega. The controller produces an output that is flat to acceleration. This is the acceleration output. This is then integrated. This "velocity output" now has a 1/omega slope with respect to acceleration. However, acceleration is the derivative of velocity, so you need to multiply by omega to consider the output with respect to velocity. Thus, the 1/omega slope created by the integrator is cancelled out by the omega relationship between slope and velocity. Make sense? Put otherwise: The V/g sensitivity is flat. If we integrate it, the V/g sensitivity has a 1/omega term. (This is different than your statement above) Switching to V/m/s takes out this 1/omega slope. Aaron > > Am I missing something? > > Regards, > Sean-Thomas > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "frank murray" Subject: 6.3 in new zealand Date: Tue, 18 May 1999 12:07:34 -0700 anybody picking this one up _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: VBB schematics Date: Wed, 19 May 1999 00:23:19 -0500 (CDT) Rex, Your package of schematics arrived last Friday the 14th along with the parts lists with catalog numbers. These lists of catalogue numbers and prices will certainly be helpful for anyone wanting to build the seismometer. I have some general comments about the set: 1. As far as I can tell, the schematics are a proper copy of what I have drawn, with the added feature that the parts are identified. I will assume that the details are correct; the notations are different from the conventions I am used to, like the op-amps having the + input on top, whereas usually the - input is on top, since the feedback is usually drawn above the amplifier from the output to the - input. Maybe your CAD program does amps with the + on top; my Autosketch draws them as on my schematics. 2. My schematics are of the circuit boards that I am using, which are recycled from the tiltmeter project. So some components are optional for the VBB seis, like the zero adjust and the "zero test" pots and switch. Since the large seis has a mechanical means of centering, an electronic zero is not needed, but can be used in place of a zero motor, but it has to be considered a potential noise source. The "zero test" is left over from being able to measure the net accumulated tilt of a tiltmeter in the ground, so it is more of a designer option that is still useful for checking the system noise. The very high price of these pots ($87) is not necessary; $15 pots will do. The mechanical zeroing motor is only $25. 3. Not all the resistors, like half of them, need to be 1%, which might make a difference to someone digging in their own bins. The ones that need to be 1%, either because of needed precision or thermal stability, should be so marked. 4. All the pots need the precision of 10 or 20 turn control rather than single turn, like the Spectrol "70" series or the Bourns 3005 series, for about $7. These have an overall accuracy of only 10%, but 50ppm stability. 5. I would hope to clearly indicate just what is essential for a VBB sensor. I provided the schematic of the multi-period version more as a source of suggestions and ideas than requirements, so I don't want it to cause confusion. Perhaps both the single-period and the multi-period versions should be shown. I will try to get the marked up set back to you in a week or two. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: Cheap air fares to Denver? Date: Wed, 19 May 1999 13:54:54 -0600 (MDT) Hi Ted, I wish there were a low fare that would allow you and your son to visit us in Colorado. Keep an eye out for a low fare and we'll have a special meeting in your honor. JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: Cheap air fares to Denver? Date: Wed, 19 May 1999 13:59:58 -0600 (MDT) Hi Larry, That offer goes for you too! JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ted Blank Subject: Re: Cheap air fares to Denver? Date: Wed, 19 May 1999 16:33:45 -0700 (PDT) Having this tour on video would be a nice asset for the PSN archives. Would someone who is going mind toting along a camcorder and recording the tour of both USGS and the Lahr "vault"... I'll be happy to pay for the tape and make copies for anyone who wants one. Don't forget to get the PSN folks on tape too! Ted Blank San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: meredith lamb Subject: Re: PSN/CoPEPP Meeting - May 21, 1999 Date: Wed, 19 May 1999 20:17:10 -0600 Ted and whomever, Plan to bring along my digital camera and take alot of still shots. Also plan to get them on my Geocities site a.s.a.p. afterward. Am aiming for about 24 shots on 6 long pages, but if more turn out well, I'll probably put up more. The Geocities site is being rebuilt, and so, there isn't much there at the moment. It will take afew days before they start showing up afterward. Last years meeting was ALOT of fun and exciting. John and Jan Lahr are super hosts, and the guests were most entertaining. Main Web site: http://www.users.uswest.net/~psnseismograph52/Index.html and.... http://www.geocities.com/ResearchTriangle/Facility/1739/ (which is being rebuilt, but, you can check as it progresses) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rex Klopfenstein, Jr." Subject: Re: VBB schematics Date: Thu, 20 May 1999 17:17:35 -0400 S-T Morrissey wrote: > Rex, > 1. As far as I can tell, the schematics are a proper copy of what I > have drawn, with the added feature that the parts are identified. I > will assume that the details are correct; the notations are different > from the conventions I am used to, like the op-amps having the + input > on top, whereas usually the - input is on top, since the feedback > is usually drawn above the amplifier from the output to the - input. > Maybe your CAD program does amps with the + on top; my Autosketch > draws them as on my schematics. I the library program I have. Also, I tend to draw non-inverting a little different than you. > > > 2. My schematics are of the circuit boards that I am using, which are > recycled from the tiltmeter project. So some components are optional > for the VBB seis, like the zero adjust and the "zero test" pots and > switch. Since the large seis has a mechanical means of centering, an > electronic zero is not needed, but can be used in place of a zero motor, > but it has to be considered a potential noise source. The "zero test" > is left over from being able to measure the net accumulated tilt of a > tiltmeter in the ground, so it is more of a designer option that is > still useful for checking the system noise. The very high price of > these pots ($87) is not necessary; $15 pots will do. The mechanical > zeroing motor is only $25. You are answering just the questions I wanted you to answer! I actually wanted to get everything down and then start removing parts not needed. > > > 3. Not all the resistors, like half of them, need to be 1%, which might > make a difference to someone digging in their own bins. The ones that > need to be 1%, either because of needed precision or thermal stability, > should be so marked. I realize that most of the resistors used to set gains on opamps should be 1%, maybe you could mark the resistors that you think should be 1%. Actually I have been using 1% on about everything. I usually end up having to order something and usually have a hard time getting to the $25 minimum to save handling charge. > > > 4. All the pots need the precision of 10 or 20 turn control rather than > single turn, like the Spectrol "70" series or the Bourns 3005 series, > for about $7. These have an overall accuracy of only 10%, but 50ppm stability. No problem!! > > > 5. I would hope to clearly indicate just what is essential for a VBB > sensor. I provided the schematic of the multi-period version more as a > source of suggestions and ideas than requirements, so I don't want it to > cause confusion. Perhaps both the single-period and the multi-period > versions should be shown. Again, I just wanted to everything down! I most likely will only use the 1 and 80 second range with a simple toggle. If I remember the 1 second is necessary for zeroing. -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: NEW JAVA SEISMIC APPLET WEB PAGE Date: Sat, 22 May 1999 15:06:05 +0200 Hi to all. It's now available on our web site, a new page called "SEISMOGRAM = VIEWER" with a experimental Java programm. You can visualize and elaborate interactively on these page the = waveforms of the event recordered by IESN. Phases, picks, integrata = data, zoom etc.; Help on-line. It's need to have a broswer with java capabilities (Explorer or = Netscape, 3.x or higher vers.). See at: http://space.tin.it/scienza/frnucer/English.htm > seismogram = viewer link boutton Regards Francesco Nucera
Hi to all.
It's now available on our web site, = a new page=20 called "SEISMOGRAM VIEWER" with a experimental Java=20 programm.
You can visualize and elaborate = interactively on=20 these page the waveforms of the event recordered by IESN.  Phases, = picks,=20 integrata data, zoom etc.; Help on-line.
 
It's need to have a broswer with = java=20 capabilities (Explorer or Netscape, 3.x or higher vers.).
 
See at:  http://space.tin= ..it/scienza/frnucer/English.htm  =20 > seismogram viewer link boutton
 
Regards
Francesco = Nucera
From: meredith lamb Subject: The 2nd annual Colorado PSN meeting pictures Date: Sat, 22 May 1999 19:12:30 -0600 Hi All, Now have the 5/21/99 PSN meeting pictures up on a web site. http://www.geocities.com/ResearchTriangle/Facility/1739/New010.html This total web site is being rebuilt, but, the above should get you through 11 pages of some 66 pictures. There are some errors therein I'am sure, but if anyone has corrections please let me know. Wow.....that was some meeting, with some 3 speakers in various areas of the NEIC building, with pizza later. John Lahr hosted, but with talks from Waverly Person, John McMillan, Mark Meremonte and unwavering assistance throughout by Edward Cranswick. Dave Nelson also put on a slide show of New Zealand after the pizza break, which was very interesting. Be prepared to spend some time reviewing the pictures, as your download time could vary. If anyone wants a particular copy of a picture/s, please note the particular page (i.e. New015 etc), and denote which one from the top you desire, and drop me a email too: psnseismograph52@.......... All the pictures are jpg variety. You may use them for any purpose of course. Afew didn't turn out too well, but it is the nature of my lack of acquaintance with digital cameras I think. Many thanks to all the USGS NEIC employees and all for a very enjoyable get together. -- Meredith Lamb Main Web site: http://www.users.uswest.net/~psnseismograph52/Index.html and.... http://www.geocities.com/ResearchTriangle/Facility/1739/ (which is being rebuilt, but, you can check as it progresses) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: meredith lamb Subject: The Colorado PSN annual meeting pictures Date: Sat, 22 May 1999 19:45:44 -0600 Hi all, Hmmm, I see the address listed now comes up blank for the pictures...could be geocites or? Anyway, use the bottom address and drop down to the right of the index page and click on the "The 2nd annual Colorado PSN meeting (1999)", that should do it. -- Meredith Lamb Main Web site: http://www.users.uswest.net/~psnseismograph52/Index.html and.... http://www.geocities.com/ResearchTriangle/Facility/1739/ (which is being rebuilt, but, you can check as it progresses) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: ACole65464@....... Subject: Re: The Colorado PSN annual meeting pictures Date: Sat, 22 May 1999 23:52:22 EDT Meredith, Thank you for providing the photos of the past PSN meeting. I have visited NEIC on 2 occasions and each time someone was willing to give me a tour. You need to call ahead to make sure that there will be a person with the time to give a tour though. They are a friendly bunch of folks. For me, it is the number 1 place in Colorado to visit. Allan Coleman Edmonds, Washington _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: The Lahrs Subject: Re: The 2nd annual Colorado PSN meeting pictures Date: Sun, 23 May 1999 09:26:03 -0600 Meredith! Thanks for the great photographic report on the PSN meeting in Golden. You would be a terrific newspaper reporter. I would like to thank again Waverly Person, John McMillan, and Mark Meremonte for their very interesting talks. And, many thanks go to Ed Cranswick, who co-hosted the meeting and provided the delicious pizzas and informative posters. Participants included: Dennis Ambrisco Wesstminster, CO Edward Cranswick Golden, CO John Lahr Golden, CO Lee Ann Lamb Denver, CO Meredith Lamb Denver, CO David Latsch Boulder, CO Margaret McDde Evergreen, CO Mark Meremonte Evergreen, CO Dave Nelson Dunedin, New Zealand Terry Wilkinson Aurora, CO We'll have to do this again in 2000. Cheers, John * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * AOL version of homepage: * * http://lahr.org/john-jan/homepage.html * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: ASCII FORMAT Date: Mon, 24 May 1999 18:10:49 +0200 Someone konws if it's available a conversion program ascii > sac_binary = or other format readeble by WQ (GSE2.0 example)? Thank you for the help. Francesco Nucera
Someone konws if it's available a conversion program ascii > = sac_binary=20 or other format readeble by WQ (GSE2.0  example)?
 
Thank you for the help.
 
Francesco Nucera
From: Karl Cunningham Subject: Re: ASCII FORMAT Date: Mon, 24 May 1999 14:01:12 -0700 Francesco -- I have some C++ source code to convert ascii to Winquake format. It is meant to read in ascii data in spreadsheet form (one line per data point). You may have to modify it for your data format. I'd be happy to send it to you as an email attachment if you would like. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... At 06:10 PM 5/24/99 +0200, you wrote: >>>> Someone konws if it's available a conversion program ascii > sac_binary or other format readeble by WQ (GSE2.0 example)? Thank you for the help. Francesco Nucera <<<<<<<< _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: ASCII FORMAT Date: Mon, 24 May 1999 18:28:09 -0700 Francesco Also Quickbasic has a conversion command. If you are to use a program to make the conversion yourself there is an order to the header info data (Ist 100 bytes if I remember correctly). After the header there is the two byte integer data. What I do is save the data in an integer array(say of dimension 25000) then I "BSAVE" the the array. Barry Francesco wrote: > Someone konws if it's available a conversion program ascii > > sac_binary or other format readeble by WQ (GSE2.0 example)? Thank you > for the help. Francesco Nucera Francesco
    Also Quickbasic has a conversion command. If you are to use a program to make the
conversion yourself there is an order to the header info data (Ist 100 bytes if I remember correctly). After the header there is the two byte integer data. What I do is save the data in an integer array(say of dimension 25000) then I  "BSAVE"  the the array.
Barry

Francesco wrote:

Someone konws if it's available a conversion program ascii > sac_binary or other format readeble by WQ (GSE2.0  example)? Thank you for the help. Francesco Nucera
From: Larry Cochrane Subject: Re: ASCII FORMAT Date: Mon, 24 May 1999 18:55:31 -0700 Francesco, The latest WQ will read in an ASCII event file. Too see what the format looks like save an event file in the ASCII format and look at the file with an editor. There must be a header section before the data that looks like this: ! PSN ASCII Event File Format 1.0 <<---- must be the first line. Start Time: 1999/05/24 01:04:11.0 <<---- must have this field. Number of Samples: 14950 <<---- must have this field. SPS: 50.000000 <<---- must have this field. Comment: Md2.2 49km from Redwood City,Ca, 16 km E of San Jose, CA A/D Converter Bits: Data Minimum: -220.000000 Data Maximum: 220.000000 ! Sensor Information: <<------ should have this info Sensor Location: Redwood City,Ca Sensor Latitude: 37.497000 Sensor Longitude: -122.241000 Sensor Orientation: N ! Event Information: Event Latitude: 37.360000 Event Longitude: -121.719000 Event Time: 1999/05/24 01:05:45.0 Event Magnitude: Md 2.2 Event Depth: 8.2 ! WinQuake Information: Magnitude Correction: 0.0015 Mb Magnitude Correction: 0.001 Ms Period: 20.000000 Mb Period: 1.000000 Md Duration: PS Pick Information: ! SDR Information: Lock Indicator: L Data: 22 19 .... <<----- = my notes and are not part of the data. Not all of the fields need to be in the header, I have marked the ones needed, and they can be in any order. Hope this helps. -Larry Cochrane At 06:10 PM 5/24/99 +0200, you wrote: >>>> Someone konws if it's available a conversion program ascii > sac_binary or other format readeble by WQ (GSE2.0 example)? Thank you for the help. Francesco Nucera <<<<<<<< _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: 2nd Spring Colorado PSN Meeting Date: Tue, 25 May 1999 08:55:08 -0600 (MDT) Somehow I left Raul Alvarez and Dave Wolny off of the participants list! Here's a corrected version. If I missed anyone else, please let me know. John 2nd Spring Colorado PSN Meeting Participants Raul Alvarez Bellvue, Colorado Dennis Ambrisco Wesstminster, CO Edward Cranswick Golden, CO John Lahr Golden, CO Lee Ann Lamb Denver, CO Meredith Lamb Denver, CO David Latsch Boulder, CO Margaret McDde Evergreen, CO Mark Meremonte Evergreen, CO Dave Nelson Dunedin, New Zealand Terry Wilkinson Aurora, CO Dave Wolny Grand Juntion, CO _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: 2nd Spring Colorado PSN Meeting Date: Tue, 25 May 1999 09:02:00 -0600 (MDT) (With some typos corrected) Somehow I left Raul Alvarez and Dave Wolny off of the participants list! Here's a corrected version. If I missed anyone else, please let me know. John 2nd Spring Colorado PSN Meeting Participants Raul Alvarez Bellvue, Colorado Dennis Ambrisco Westminster, CO Edward Cranswick Golden, CO John Lahr Golden, CO Lee Ann Lamb Denver, CO Meredith Lamb Denver, CO David Latsch Boulder, CO Margaret McDde Evergreen, CO Mark Meremonte Evergreen, CO Dave Nelson Dunedin, New Zealand Terry Wilkinson Aurora, CO Dave Wolny Grand Junction, CO _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ted Blank Subject: Re: ASCII FORMAT Date: Tue, 25 May 1999 08:47:48 -0700 (PDT) The original PSN format file had 50207 bytes. 25000 two byte integers took up 50000. 100 two byte integers for the header accounted for 200, and the BSAVE header was another 7 bytes. The original format had some deficiencies (like not storing the max and min for the A/D) so Larry and I developed the "new" format via e-mail when I was in Tokyo. It packed more information into the header by using both bytes of the two-byte integers wherever possible, while leaving the size of the file unchanged. The header formats are documented on the PSN web site. Ted Blank San Jose, California On Mon, 24 May 1999, barry lotz wrote: > Francesco > Also Quickbasic has a conversion command. If you are to use a > program to make the > conversion yourself there is an order to the header info data (Ist 100 > bytes if I remember correctly). After the header there is the two byte > integer data. What I do is save the data in an integer array(say of > dimension 25000) then I "BSAVE" the the array. > Barry > > Francesco wrote: > > > Someone konws if it's available a conversion program ascii > > > sac_binary or other format readeble by WQ (GSE2.0 example)? Thank you > > for the help. Francesco Nucera > Francesco
    Also Quickbasic has a conversion command. If you are to use a program to make the
conversion yourself there is an order to the header info data (Ist 100 bytes if I remember correctly). After the header there is the two byte integer data. What I do is save the data in an integer array(say of dimension 25000) then I  "BSAVE"  the the array.
Barry

Francesco wrote:

Someone konws if it's available a conversion program ascii > sac_binary or other format readeble by WQ (GSE2.0  example)? Thank you for the help. Francesco Nucera
From: Ted Blank Subject: Re: The Colorado PSN annual meeting pictures Date: Tue, 25 May 1999 08:49:43 -0700 (PDT) Meredith, this is a great set of pictures. Thank you for getting the people as well as the equipment - it's nice to be able to put a face with a name (and an e-mail address). Ted Blank San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ted Blank Subject: Re: ASCII FORMAT Date: Tue, 25 May 1999 08:53:15 -0700 (PDT) My previous msg got sent as an attachment - dont' know how that happened. Anyway here it is as text: The original PSN format file had 50207 bytes. 25000 two byte integers took up 50000. 100 two byte integers for the header accounted for 200, and the BSAVE header was another 7 bytes. The original format had some deficiencies (like not storing the max and min for the A/D) so Larry and I developed the "new" format via e-mail when I was in Tokyo. It packed more information into the header by using both bytes of the two-byte integers wherever possible, while leaving the size of the file unchanged. The header formats are documented on the PSN web site. Ted Blank San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: R: ASCII FORMAT Date: Tue, 25 May 1999 18:25:34 +0200 Thany you all, for the help. I tried to convert my ascii file (it's a report by ING, Rome), which = have a strange format (more header strings than our PSN format), editing = the same as such Larry have told me. Not good = results..............because the file (and its data) is a record of a = particular accelerometer...! For curiosity, the header below is the original of the ascii file. I = don't attach the data because its too great. Francesco -------------------------------------------------------------------------= ------- RA01137 ORIGIN TIME : EPICENTRE : Lat. Lon. 42.92 13.01 MAGNITUDE : Ml 4.1 HYPOCENTRAL DEPTH : 8.50 EPICENTRAL MACRO INTENSITY : V ------------------------------ RECORDED NOCERA UMBRA DATE RECORD : 07-09-1997 23 28 07 STATION CODE : NCR COORDINATE : Lat. 43 6 46 Lon. 12 47 7 SITE INSTALLATION : 1 TYPE INSTALLATION : 1 MORFOLOGICAL CHAR. : GEOTECHNICAL CHAR. : 3 GEOTECHNICAL DATA : EPICENTRAL DISTANCE : FAULT DISTANCE : LOCAL MACROSEISMIC INTENSITY : MCS ------------------------------ RECORD. INSTRUMENT : RAKA297 FULL SCALE : 0.500 G SENSIBILITY : 3.548 cm/g NATURAL FREQ. : 19.000 Hz DAMPING : 57.000 % ------------------------------ COMP : NS UNCORRECTED DATA AUTOMATIC DIG. FIX SAMPLING TIME : .00846666 SUBTRACTED MEDIUM VALUE AND POSITIONED FT OR FC SUBTRACTED AMAX : 55.250 CM/SEC**2 TIME (AMAX) : .140 SEC TOTAL DURATION : 22.929 SEC RMS : 4.644 CM/SEC**2 UNITS ARE : SEC CM/SEC**2 POINTS : 4587 =FF=FE<=00!=00D=00O=00C=00T=00Y=00P=00E=00 =00H=00T=00M=00L=00 = =00P=00U=00B=00L=00I=00C=00 = =00"=00-=00/=00/=00W=003=00C=00/=00/=00D=00T=00D=00 =00H=00T=00M=00L=00 = =004=00.=000=00 = =00T=00r=00a=00n=00s=00i=00t=00i=00o=00n=00a=00l=00/=00/=00E=00N=00"=00>=00= =0D=00=0A= =00<=00H=00T=00M=00L=00>=00<=00H=00E=00A=00D=00>=00=0D=00=0A= =00<=00M=00E=00T=00A=00 = =00c=00o=00n=00t=00e=00n=00t=00=3D=00"=00t=00e=00x=00t=00/=00h=00t=00m=00= l=00;=00 = =00c=00h=00a=00r=00s=00e=00t=00=3D=00u=00n=00i=00c=00o=00d=00e=00"=00 = =00h=00t=00t=00p=00-=00e=00q=00u=00i=00v=00=3D=00C=00o=00n=00t=00e=00n=00= t=00-=00T=00y=00p=00e=00>=00=0D=00=0A= =00<=00M=00E=00T=00A=00 = =00c=00o=00n=00t=00e=00n=00t=00=3D=00"=00M=00S=00H=00T=00M=00L=00 = =005=00.=000=000=00.=002=000=001=004=00.=002=001=000=00"=00 = =00n=00a=00m=00e=00=3D=00G=00E=00N=00E=00R=00A=00T=00O=00R=00>=00=0D=00=0A= =00<=00S=00T=00Y=00L=00E=00>=00<=00/=00S=00T=00Y=00L=00E=00>=00=0D=00=0A= =00<=00/=00H=00E=00A=00D=00>=00=0D=00=0A= =00<=00B=00O=00D=00Y=00 = =00b=00g=00C=00o=00l=00o=00r=00=3D=00#=00f=00f=00f=00f=00f=00f=00>=00=0D=00=0A= =00<=00D=00I=00V=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=002=00>=00T=00h=00a=00n=00y=00 =00y=00o=00u=00 = =00a=00l=00l=00,=00 =00f=00o=00r=00 =00t=00h=00e=00 = =00h=00e=00l=00p=00.=00<=00/=00F=00O=00N=00T=00>=00<=00/=00D=00I=00V=00>=00= =0D=00=0A= =00<=00D=00I=00V=00>=00&=00n=00b=00s=00p=00;=00<=00/=00D=00I=00V=00>=00=0D= =00=0A= =00<=00D=00I=00V=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=002=00>=00I=00 =00t=00r=00i=00e=00d=00 = =00t=00o=00 =00c=00o=00n=00v=00e=00r=00t=00 =00m=00y=00 = =00a=00s=00c=00i=00i=00 =00f=00i=00l=00e=00 =00(=00i=00t=00'=00s=00 = =00a=00 =00r=00e=00p=00o=00r=00t=00 =00b=00y=00 =00I=00N=00G=00,=00 = =00R=00o=00m=00e=00)=00,=00 =00=0D=00=0A= =00w=00h=00i=00c=00h=00 =00h=00a=00v=00e=00 =00a=00 = =00s=00t=00r=00a=00n=00g=00e=00 =00f=00o=00r=00m=00a=00t=00 = =00(=00m=00o=00r=00e=00 =00h=00e=00a=00d=00e=00r=00 = =00s=00t=00r=00i=00n=00g=00s=00 =00t=00h=00a=00n=00 =00o=00u=00r=00 = =00P=00S=00N=00 =00f=00o=00r=00m=00a=00t=00)=00,=00 = =00e=00d=00i=00t=00i=00n=00g=00 =00=0D=00=0A= =00t=00h=00e=00 =00s=00a=00m=00e=00 =00a=00s=00 =00s=00u=00c=00h=00 = =00L=00a=00r=00r=00y=00 =00h=00a=00v=00e=00 =00t=00o=00l=00d=00 = =00m=00e=00.=00 =00N=00o=00t=00 =00g=00o=00o=00d=00 = =00r=00e=00s=00u=00l=00t=00s=00.=00.=00.=00.=00.=00.=00.=00.=00.=00.=00.=00= ..=00.=00.=00b=00e=00c=00a=00u=00s=00e=00 =00t=00h=00e=00 =00=0D=00=0A= =00f=00i=00l=00e=00 =00(=00a=00n=00d=00 =00i=00t=00s=00 = =00d=00a=00t=00a=00)=00 =00i=00s=00 =00a=00 =00r=00e=00c=00o=00r=00d=00 = =00o=00f=00 =00a=00 =00p=00a=00r=00t=00i=00c=00u=00l=00a=00r=00 = =00a=00c=00c=00e=00l=00e=00r=00o=00m=00e=00t=00e=00r=00.=00.=00.=00!=00<=00= /=00F=00O=00N=00T=00>=00<=00/=00D=00I=00V=00>=00=0D=00=0A= =00<=00D=00I=00V=00>=00&=00n=00b=00s=00p=00;=00<=00/=00D=00I=00V=00>=00=0D= =00=0A= =00<=00D=00I=00V=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=002=00>=00F=00o=00r=00 = =00c=00u=00r=00i=00o=00s=00i=00t=00y=00,=00 =00t=00h=00e=00 = =00h=00e=00a=00d=00e=00r=00 =00b=00e=00l=00o=00w=00 =00i=00s=00 = =00t=00h=00e=00 =00o=00r=00i=00g=00i=00n=00a=00l=00 =00o=00f=00 = =00t=00h=00e=00 =00a=00s=00c=00i=00i=00 =00=0D=00=0A= =00f=00i=00l=00e=00.=00 =00I=00 =00d=00o=00n=00'=00t=00 = =00a=00t=00t=00a=00c=00h=00 =00t=00h=00e=00 =00d=00a=00t=00a=00 = =00b=00e=00c=00a=00u=00s=00e=00 =00i=00t=00s=00 =00t=00o=00o=00 = =00g=00r=00e=00a=00t=00.=00<=00/=00F=00O=00N=00T=00>=00<=00/=00D=00I=00V=00= >=00=0D=00=0A= =00<=00D=00I=00V=00>=00&=00n=00b=00s=00p=00;=00<=00/=00D=00I=00V=00>=00=0D= =00=0A= =00<=00D=00I=00V=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=002=00>=00F=00r=00a=00n=00c=00e=00s=00c=00o=00<=00= /=00F=00O=00N=00T=00>=00<=00/=00D=00I=00V=00>=00=0D=00=0A= =00<=00D=00I=00V=00>=00=0D=00=0A= =00<=00H=00R=00>=00=0D=00=0A= =00<=00/=00D=00I=00V=00>=00=0D=00=0A= =00<=00D=00I=00V=00>=00&=00n=00b=00s=00p=00;=00<=00/=00D=00I=00V=00>=00=0D= =00=0A= =00<=00D=00I=00V=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00R=00A=000=001=001=003=007=00<=00/=00F=00= O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00O=00R=00I=00G=00I=00N=00 = =00T=00I=00M=00E=00 = =00:=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00E=00P=00I=00C=00E=00N=00T=00R=00E=00 = =00:=00 =00L=00a=00t=00.=00 =00L=00o=00n=00.=00 = =004=002=00.=009=002=00&=00n=00b=00s=00p=00;=00 = =001=003=00.=000=001=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00M=00A=00G=00N=00I=00T=00U=00D=00E=00 = =00:=00 =00M=00l=00 = =004=00.=001=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00H=00Y=00P=00O=00C=00E=00N=00T=00R=00A=00= L=00 =00D=00E=00P=00T=00H=00 =00:=00 = =008=00.=005=000=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00E=00P=00I=00C=00E=00N=00T=00R=00A=00L=00= =00M=00A=00C=00R=00O=00 =00I=00N=00T=00E=00N=00S=00I=00T=00Y=00 =00:=00 = =00V=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00= -=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-= =00-=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00R=00E=00C=00O=00R=00D=00E=00D=00 = =00N=00O=00C=00E=00R=00A=00 =00U=00M=00B=00R=00A=00 =00D=00A=00T=00E=00 = =00R=00E=00C=00O=00R=00D=00 =00:=00 = =000=007=00-=000=009=00-=001=009=009=007=00 =002=003=00 =002=008=00 = =00=0D=00=0A= =000=007=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00S=00T=00A=00T=00I=00O=00N=00 = =00C=00O=00D=00E=00 =00:=00 =00N=00C=00R=00 = =00C=00O=00O=00R=00D=00I=00N=00A=00T=00E=00 =00:=00 =00L=00a=00t=00.=00 = =004=003=00 =006=00 =004=006=00 =00L=00o=00n=00.=00 =001=002=00 = =004=007=00 =00=0D=00=0A= =007=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00S=00I=00T=00E=00 = =00I=00N=00S=00T=00A=00L=00L=00A=00T=00I=00O=00N=00 =00:=00 = =001=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00T=00Y=00P=00E=00 = =00I=00N=00S=00T=00A=00L=00L=00A=00T=00I=00O=00N=00 =00:=00 = =001=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00M=00O=00R=00F=00O=00L=00O=00G=00I=00C=00= A=00L=00 =00C=00H=00A=00R=00.=00 = =00:=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00G=00E=00O=00T=00E=00C=00H=00N=00I=00C=00= A=00L=00 =00C=00H=00A=00R=00.=00 =00:=00 = =003=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00G=00E=00O=00T=00E=00C=00H=00N=00I=00C=00= A=00L=00 =00D=00A=00T=00A=00 = =00:=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00E=00P=00I=00C=00E=00N=00T=00R=00A=00L=00= =00D=00I=00S=00T=00A=00N=00C=00E=00 =00:=00 =00F=00A=00U=00L=00T=00 = =00D=00I=00S=00T=00A=00N=00C=00E=00 = =00:=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00L=00O=00C=00A=00L=00 = =00M=00A=00C=00R=00O=00S=00E=00I=00S=00M=00I=00C=00 = =00I=00N=00T=00E=00N=00S=00I=00T=00Y=00 =00:=00 = =00M=00C=00S=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00= -=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-= =00-=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00R=00E=00C=00O=00R=00D=00.=00 = =00I=00N=00S=00T=00R=00U=00M=00E=00N=00T=00 =00:=00 = =00R=00A=00K=00A=002=009=007=00 =00F=00U=00L=00L=00 = =00S=00C=00A=00L=00E=00 =00:=00 =000=00.=005=000=000=00 = =00G=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00S=00E=00N=00S=00I=00B=00I=00L=00I=00T=00= Y=00 =00:=00 =003=00.=005=004=008=00 =00c=00m=00/=00g=00 = =00N=00A=00T=00U=00R=00A=00L=00 =00F=00R=00E=00Q=00.=00 =00:=00 = =001=009=00.=000=000=000=00 =00H=00z=00 =00D=00A=00M=00P=00I=00N=00G=00 = =00:=00 =00=0D=00=0A= =005=007=00.=000=000=000=00 = =00%=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00= -=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-=00-= =00-=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00C=00O=00M=00P=00 =00:=00 =00N=00S=00 = =00U=00N=00C=00O=00R=00R=00E=00C=00T=00E=00D=00 = =00D=00A=00T=00A=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00A=00U=00T=00O=00M=00A=00T=00I=00C=00 = =00D=00I=00G=00.=00 =00F=00I=00X=00 =00S=00A=00M=00P=00L=00I=00N=00G=00 = =00T=00I=00M=00E=00 =00:=00 = =00.=000=000=008=004=006=006=006=006=00<=00/=00F=00O=00N=00T=00>=00<=00/=00= P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00S=00U=00B=00T=00R=00A=00C=00T=00E=00D=00= =00M=00E=00D=00I=00U=00M=00 =00V=00A=00L=00U=00E=00 =00A=00N=00D=00 = =00P=00O=00S=00I=00T=00I=00O=00N=00E=00D=00<=00/=00F=00O=00N=00T=00>=00<=00= /=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00F=00T=00 =00O=00R=00 =00F=00C=00 = =00S=00U=00B=00T=00R=00A=00C=00T=00E=00D=00<=00/=00F=00O=00N=00T=00>=00<=00= /=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00A=00M=00A=00X=00 =00:=00 = =005=005=00.=002=005=000=00 =00C=00M=00/=00S=00E=00C=00*=00*=002=00 = =00T=00I=00M=00E=00 =00(=00A=00M=00A=00X=00)=00 =00:=00 = =00.=001=004=000=00 = =00S=00E=00C=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00T=00O=00T=00A=00L=00 = =00D=00U=00R=00A=00T=00I=00O=00N=00 =00:=00 =002=002=00.=009=002=009=00 = =00S=00E=00C=00 =00R=00M=00S=00 =00:=00 =004=00.=006=004=004=00 = =00C=00M=00/=00S=00E=00C=00*=00*=002=00<=00/=00F=00O=00N=00T=00>=00<=00/=00= P=00>=00=0D=00=0A= =00<=00P=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=001=00>=00U=00N=00I=00T=00S=00 =00A=00R=00E=00 = =00:=00 =00S=00E=00C=00 =00C=00M=00/=00S=00E=00C=00*=00*=002=00 = =00P=00O=00I=00N=00T=00S=00 =00:=00 =00=0D=00=0A= =004=005=008=007=00<=00/=00F=00O=00N=00T=00>=00<=00/=00P=00>=00<=00/=00D=00= I=00V=00>=00<=00/=00B=00O=00D=00Y=00>=00<=00/=00H=00T=00M=00L=00>=00=0D=00=0A= =00 From: Ted Blank Subject: Re: The Colorado PSN annual meeting pictures Date: Tue, 25 May 1999 16:16:11 -0700 (PDT) Hmm, doesn't look like my previous note got through...it was to thank Meredith for putting the great pictures on the web, and for also snapping pictures of the people as well as the sensors! Ted Blank San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: Re: The Colorado PSN annual meeting pictures Date: Tue, 25 May 1999 20:01:33 -0500 (CDT) I also want to thank Meredith for all the fine photos of the instruments and of the people at the meeting. It is nice to see some of the details of John Lahr's instrument. I wonder if the signal cable comming off the boom at the lower pivot is flexible enough though. It looks pretty substantial; we ususally use a coiled pigtail of small ( like #36) wire for each of the four connections across the hinge. Heavy leads will make noise. By way of footnote about the Seismoscope: I had one in place at Adak in the Aleutians at the time of the M 7.7 in May of 1986, and it recorded most of the ground motion quite well with its static magnification of 2. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: meredith lamb Subject: Re: The Colorado PSN annual meeting pictures Date: Tue, 25 May 1999 23:50:37 -0600 Ted, John, Sean-Thomas and all, Thanks for the compliments on the web photo pages. The real heros were those who made it all come about, and which shared generiously of their un-relenting support in the "meeting". I was more like a kid at Christmas there and I'am sure all my photo flashes made some people alittle uncomfortable...ha. The Geocities web site uses a very simple "Geo-Builder" web site program, which made the whole "show" very easy to do. It is a free web page program, and, with some 11meg of space, its easier than my other USWest Netscape program, and, with the 2meg limitation on USWest...the choice is with Geocities. Of course, if I change my local ISP service from USWest, to another some time, I won't lose the Geocities contact from it. I found the whole thing very exciting and worthwhile for anyone interested in amateur seismology. I would recommend it too anyone that can make the trip....presuming of course....that next years meeting is held, and, at the same place. USGS, and the NEIC environment is really the ultimate place to visit. Even though its been afew days since the web site has been up, I'am finding more words, corrections, and photo changes and blow-ups, to make almost daily changes. Hopefully soon it will settle down permanently. Some of the clickable references have not been making contact occasionally, but sooner or later they all seem too. Not being much of a photographic person, I do wonder about what kind of equipment, brand, accessories might make adequate closeups of subjects? The HP Photo Smart C20, that I used just doesn't cut it for small details, nor, is there any accessories along that line. Any reasonable priced digital camera ideas that focus within 6 inches? It would have been nice to get the juicy seismometer/s mechanical details for more understanding....... Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Fred Subject: REMOVE Date: Wed, 26 May 1999 00:18:29 -0700 REMOVE -- War does not determine who is right. War determines who is left. \ | / ( oo ) ---------000o---(_)---o000------------ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: The Colorado PSN annual meeting pictures Date: Wed, 26 May 1999 10:03:40 -0600 Meredith- > Even though its been afew days since the web site has been up, > I'am finding more words, corrections, and photo changes and > blow-ups, to make almost daily changes. I was very impressed not only by what a great job you have done of documenting the PSN meeting but also by how rapidly you got it on the Web. Congratulations!!! and regards to Lee Ann for her patience as an innocent bystander with all of us. -Edward PS. while you're making these changes, could you please make me look a little thinner in those pictures. -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: The Colorado PSN annual meeting pictures Date: Wed, 26 May 1999 10:17:07 -0600 (MDT) Sean, Good point about the leads across the hinge. I do need to use some finer wire. I've switched to a higher resistance coil (22 ohms) so I won't have to worry about an ohm or two in the hinge wires. I've replaced the speaker magnet with a pair of strong neodymium magnets. The arrangement is not of coaxial cylinders, as it was with the speaker coil and magnet, but it was easy to set up and gives a stronger signal than the original speaker coil/magnet setup. I'll have to see how it does on the next good teleseism. JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: meredith lamb Subject: Re: The Colorado PSN annual meeting pictures Date: Wed, 26 May 1999 11:26:44 -0600 John Lahr wrote: > Sean, > > Good point about the leads across the hinge. I do need to use > some finer wire. I've switched to a higher resistance coil > (22 ohms) so I won't have to worry about an ohm or two in the > hinge wires. I've replaced the speaker magnet with a pair > of strong neodymium magnets. The arrangement is not of > coaxial cylinders, as it was with the speaker coil and > magnet, but it was easy to set up and gives a stronger signal > than the original speaker coil/magnet setup. > > I'll have to see how it does on the next good teleseism. > > JCLahr > John, It would be interesting to see your neodymium magnet and coil arrangement sometime via the web site or whatever. I've been a somewhat ardent neo fan....particularily since the market for magnets seems to numerically have much abundance of them on the surplus scene, that the older Alnico variety..... but they do present mechanical problems of course... Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: meredith lamb Subject: Re: The Colorado PSN annual meeting pictures Date: Wed, 26 May 1999 11:37:10 -0600 Edward Cranswick wrote: > Meredith- > > > Even though its been afew days since the web site has been up, > > I'am finding more words, corrections, and photo changes and > > blow-ups, to make almost daily changes. > > I was very impressed not only by what a great job you have done of > documenting the PSN meeting but also by how rapidly you got it on the Web. > Congratulations!!! > and regards to Lee Ann for her patience as an innocent bystander with > all of us. > -Edward > PS. while you're making these changes, could you please make me look a > little thinner in those pictures. > > -- > Edward Cranswick Tel: 303-273-8609 > US Geological Survey, MS 966 Fax: 303-273-8600 > PO Box 25046, Federal Center cranswick@........ > Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". > Ed, Thanks for the nice words. But thanks very much for your extensive support and help throughout the "meeting". I'am not sure whether Lee Ann got the opportunity to bug you somewhere in the meeting, as I was often running around like crazy....but, you probably deserved the "harrassment"-ha. She enjoyed the meeting very much. Hmmm.....I would bet most of us would gladly "instantly", trade our physiques for yours anytime.....ha. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: coils, boom pigtails Date: Wed, 26 May 1999 14:10:48 -0500 (CDT) John, As you have correctly surmised, the speaker coil and magnet is not an optimal transducer for a velocity sensor, where the latter needs a strong magnetic field but is not especially concerned about its shape, and needs all the turns of the coil that will fit in the gap, since the output increases as the square root of the coil resistance (everything else being equal). The low resistance and high G constant and linearity is mostly needed for a VBB fedback configuration. I suspect that you have decreased the strength of your speaker magnet by enlarging the gap, which I have also attempted (without, however, dismantling the magnet), although I would like to use a gaussmeter to study the amount of the change . If you are concerned about the resistance of the fine leads across the boom hinge affecting the ability to damp a low resistance coil, the damping resistance can be installed on the boom at the coil. The amplifier input resistance is high enough (100k ohms) that little current is involved, so the fine leads across the hinges are not a problem. I make the fine coiled pigtails with a very large darning needle; I start the fine wire in the eye, then twirl the needle between my fingers to tightly wind about a hundred turns along its length. The coil slides off easily, and when stretched to 2x to 4x, makes a nice pigtail. Use the "Beldsol" insulated wire that has insulation that melts when you solder it (I can mail you some). A pigtail made with a 4cm long winding of #36 wire on a 5cm darning needle has a resistance of 1.6 ohms. It can be stretched to make two 5 cm pigtails. Regarding the NEXT Colorado PSN meeting, perhaps a few months of notice could be arranged so that some of us foreigners (I am actually a "NATIVE", being raised in Lakewood) might fine a way to wrangle, coerce, finagle, etc., a way to get to it. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: =?US-ASCII?Q?Re:_coils,_boom_pigtails=1B?= Date: Wed, 26 May 1999 14:00:27 -0600 (MDT) Hi Sean-Thomas, I agree that next year we should plan the meeting a bit farther in advance! The timing of this one was driven by the opportunity to have Dave Nelson meet with a few of us while he was in town. I'll take apart the windings from a small tape recorder transformer to get some very fine wire for the hinge. Don't you think that should work? Thanks for the description of the use of a darning needle to make the pigtails. At some point I'll try to get a picture of my current coil/magnet system on the web. Cheers, JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: meredith lamb Subject: The island of Hawaii Date: Wed, 26 May 1999 18:13:01 -0600 Tony, What is the Puu o'o exactly, per your event reference? A town or landmark? I presume the swarm continues as we speak....I know its near that volcano that keeps emitting lava but.....? -- Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Bonnie Schafer" Subject: Re: Busy day in California.... Date: Wed, 26 May 1999 19:03:11 -0700 Hi, I believe that animals can sense an approaching quake. When we had a quake in Alhambra, several months ago, my 'til about drove me nuts all day. I notice when there is quake activity around he gets really noisy and screechy. I used to have a little parrot that could predict quakes better than any animal I have seen since. In the '80's we had quakelette swarms in Palm Springs. My little parrot was a catty bird but about ten seconds before a shock he would get just as still as could be. Then, the shock would hit and he would start chattering again. I always new when one was coming because of him. Wish I still had him. I haven't exactly figured out any pattern that these birds exhibit before quakes but am trying. Bonnie the crafty crafter _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: Busy day in California.... Date: Wed, 26 May 1999 21:15:23 -0700 (MST) On Wed, 26 May 1999, Bonnie Schafer wrote: > Hi, I believe that animals can sense an approaching quake. When we had a > quake in Alhambra, several months ago, my 'til about drove me nuts all day. > I notice when there is quake activity around he gets really noisy and > screechy. I used to have a little parrot that could predict quakes better > than any animal I have seen since. In the '80's we had quakelette swarms > in Palm Springs. My little parrot was a catty bird but about ten seconds > before a shock he would get just as still as could be. Then, the shock > would hit and he would start chattering again. I always new when one was > coming because of him. Wish I still had him. I haven't exactly figured out > any pattern that these birds exhibit before quakes but am trying. Bonnie, I was always suspicious about animals "predicting" quakes on the order of seconds before the shock hit an area. This is because the first arrivals (P-waves, etc.) can be (and usually are) much less intense than some of the later waves (e.g. surface waves especially). If you combine this with the fact that animals (especially birds) are very sensitive to motion and balance then it should be the case that they would be alerted at the small amplitude first arrivals that we humans could not feel, and then the larger waves come rolling in that we can feel. This leaves the impression that the animal predicted the quake, when it was really only reacting to its sensitive feel for these things that we do not have the ability to detect... This does not, however, reduce the usefulness of having them around to tell us that more damaging waves are on their way and will hit in a matter of seconds (time to jump for cover). Of course, if we reacted like this to every odd noise or behavior of an animal we would probably appear like total paranoid freaks to an outside observer and would probably not be correct much of the time. When the odd behavior is sufficiently strange and occurs a significant amount of time before a quake hits (more than several minutes) and is mostly reliable then I would be willing to call it a prediction. However, I have never seen a case (but I would love to see it) where these minimum requirements are fulfilled. Perhaps better resolving animal behavior could help make this possible... John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: peaches@............ (Donna Whitaker) Subject: Re: The island of Hawaii Date: Wed, 26 May 1999 19:02:44 GMT Meredith, Puu O'O is the name of the erupting cinder cone in the Volcanoes National Park. Its located about 12 miles SE of the summit of Kilauea volcano. It is the site of our long lasting eruption, over 16 years now, and is used as a locator point by the HVO. It is in a remote part of the park and is accessable only by air or by foot (about a 20 mile hike in and out) which I hiked with a friend about 3 years ago. The cone itself is about 200 feet high. For more info, current update, and pictures of Kilauea and our other volcanoes, go to HVO's website at: http://hvo.wr.usgs.gov/ I couldnt get a hold of anyone at the park observatory today to ask what is going on with this swarm. Guess they were very buisy. The last entry on the Tako list was at 1:40 HST (23:40 UTC) today. That was about 5 hours ago. They only list mag 2.0 and above so I'm pretty sure they have had more events sence then. I count 15 events over 2.0 that have been listed as of 06:01 HST. BTW, thanks for the great pictures of the USGS meeting in Colorado. Wish I could have been there. Tony >Tony, > >What is the Puu o'o exactly, per your event reference? A town >or landmark? I presume the swarm continues as we speak....I >know its near that volcano that keeps emitting lava but.....? > >-- >Meredith Lamb > > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Bob Fryer Subject: Re: Busy day in California.... Date: Thu, 27 May 1999 13:23:38 -0700 John, Thank you for the detailed explanation of ONE aspect of earthquake sensitivity in animals. However, having gathered a great many reports about the 'predictive ability' of animals from their owners over more than three years, I have developed another hypothesis which applies primarily to house pets: House pets, exhibiting unusual behavior for many minutes and hours, are often reacting to the emotions and behavior of their owners who, in turn, are reacting to subtle signals from stressed rocks along faults. The owners themselves are generally experiencing a trauma-based "allergic reaction" to the environmental cues. Note that low frequency (brainwave range) acoustical and electromagnetic signals travel great distances with little attenuation. It is difficult to study the related behavior in a laboratory because of the considerable shielding required for isolation, and the lack of adequate measuring instruments. Also, animals have no 'need' to react to signals from a distance. Unfortunately, geophysicists have little basis for comprehending the complex nature of the growing field of psychoneuroimmunology -- the study of interactions between the mind and body. Take care, Bob F On Wed, 26 May 1999, John Hernlund wrote: >Bonnie, > I was always suspicious about animals "predicting" quakes on the order of >seconds before the shock hit an area. This is because the first arrivals >(P-waves, etc.) can be (and usually are) much less intense than some of the >later waves (e.g. surface waves especially). If you combine this with the >fact that animals (especially birds) are very sensitive to motion and balance >then it should be the case that they would be alerted at the small amplitude >first arrivals that we humans could not feel, and then the larger waves come >rolling in that we can feel. This leaves the impression that the animal >predicted the quake, when it was really only reacting to its sensitive feel >for these things that we do not have the ability to detect... > This does not, however, reduce the usefulness of having them around to tell >us that more damaging waves are on their way and will hit in a matter of >seconds (time to jump for cover). Of course, if we reacted like this to every >odd noise or behavior of an animal we would probably appear like total >paranoid freaks to an outside observer and would probably not be correct much >of the time. > When the odd behavior is sufficiently strange and occurs a significant >amount of time before a quake hits (more than several minutes) and is >mostly reliable then I would be willing to call it a prediction. However, I >have never seen a case (but I would love to see it) where these minimum >requirements are fulfilled. Perhaps better resolving animal behavior could >help make this possible... > >John Hernlund >E-mail: hernlund@....... >WWW: http://www.public.asu.edu/~hernlund/ ----- earthquake WARNING research ----- --- animals, people, scientific evidence --- --- http://www.teleport.com/~bfryer --- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: meredith lamb Subject: Re: The island of Hawaii Date: Thu, 27 May 1999 17:21:51 -0600 Donna Whitaker wrote: > Meredith, > > Puu O'O is the name of the erupting cinder cone in the Volcanoes > National Park. Its located about 12 miles SE of the summit of > Kilauea volcano. It is the site of our long lasting eruption, > over 16 years now, and is used as a locator point by the HVO. > It is in a remote part of the park and is accessable only by air > or by foot (about a 20 mile hike in and out) which I hiked with a > friend about 3 years ago. The cone itself is about 200 feet high. > For more info, current update, and pictures of Kilauea and our > other volcanoes, go to HVO's website at: > > http://hvo.wr.usgs.gov/ > > I couldnt get a hold of anyone at the park observatory today to > ask what is going on with this swarm. Guess they were very buisy. > The last entry on the Tako list was at 1:40 HST (23:40 UTC) today. > That was about 5 hours ago. They only list mag 2.0 and above so > I'm pretty sure they have had more events sence then. I count 15 > events over 2.0 that have been listed as of 06:01 HST. > BTW, thanks for the great pictures of the USGS meeting in Colorado. > Wish I could have been there. > > Tony Tony, Went to your reference site, and eventually came into a bunch of gorgeous pictures in and around Pu'u "O'o cinder cone area which alot of the recent swarm of earthquakes have occurred. Some of them are fantastic pic's. The Hawaiian Volcano Observatory should really make a separate location on their web site for them; instead of having to go via Kileaua to find them normally. Anyway....for anyone interested, go to that site, go about 1/2 way down the first page,and click on the cinder cone, which is an alternate route, but most of the photo gallery pics can be double clicked to blow them up, and even download if one is so inclined. Its nice to see pictures of a area where alot of recent quakes have occurred. I envy your living area, but, thats the way life goes....ha. Thanks for the photo compliment on the PSN meeting. It was a very exciting local area event. If I could, I'd go to them all wherever they occur, but, we can't really afford it of course. I guess the Golden meeting went on about 7 hours; but it really wasn't enough time to really get into everything.....kind of overwhelming, to put it rather mildly....TOO MUCH....but alot of fun and excitement. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Phil Giannini Subject: FREE IS GOOD Date: Fri, 28 May 1999 09:07:19 -0700 Hi Guys, FYI.... I received a packet of bingo cards the other day and while looking through them I found a couple that were right up our alley. Both have web sites that should be visited, and the best part is, there are some FREE goodies too. Here are the web sites, check them out, and go for the goodies. The first is info on Analog Devices ADXL202 Accelerometer. I don't know if this is the one that Larry was experimenting with or not: http://www.analog.com/iMEMS The second is Dataq Instruments data acquisition starter kit FREEBIE offer at: http://dataq.com/023.htm Hey, free is good! Regards, Phil SFN & Z _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Re: FREE IS GOOD Date: Fri, 28 May 1999 09:17:42 -0700 Phil Giannini wrote: > some FREE goodies too. Here are the web sites, check them out, and go > for the goodies. Thanks for the good tips Phil. I thought it was spam until I saw the message headers (webtronics/PSN). ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: VBB driver circuit Date: Fri, 28 May 1999 12:29:05 -0400 To all VBB designers, Just finished the second iteration of some mods to the current VBB circuit design, aimed at reducing the effects of spring creep and other slowly-applied forces. Also allows for using smaller (non electrolytic) capacitors. Available for download as "driver2.pdf" - 42k At http://members.home.net/nordgren/public/ All comments appreciated and encouraged. Hope you find it helpful, Brett _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Phil Giannini Subject: re: free is good Date: Fri, 28 May 1999 12:37:32 -0700 Hi again gang, Sorry, I made a little typo on the address for Dataq Instruments, forgot the w's: http://www.dataq.com/023.htm. Freebie is a little A to D card that plugs into the serial port with 4 channels on board, software to make one of the 4 channels go, some docs, and more. Mine is on its way. Hey, a guy's gotta play. Right? Phil _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: meredith lamb Subject: Re: FREE IS GOOD Date: Fri, 28 May 1999 13:55:04 -0600 Phil Giannini wrote: > Hi Guys, > FYI.... I received a packet of bingo cards the other day and while > looking through them I found a couple that were right up our alley. Both > have web sites that should be visited, and the best part is, there are > some FREE goodies too. Here are the web sites, check them out, and go > for the goodies. > The first is info on Analog Devices ADXL202 Accelerometer. I don't > know if this is the one that Larry was experimenting with or not: > > http://www.analog.com/iMEMS > > The second is Dataq Instruments data acquisition starter kit FREEBIE > offer at: > > http://dataq.com/023.htm > > Hey, free is good! > > Regards, Phil > > SFN & Z Phil and all, Went to both sites. Both are really business orientated and you can probably expect salemen calls or email, if you go the full route. I did fill out the Dataq form (also business orientated). The device they could send (if they accept me, which I question?), is a 4 input device, BUT, if you wish to activate more than one channel, you have to pay about $50.00 to have it unlocked so to speak. 4 to 6 week delivery so they say. Still......if I do get it, it would be interesting to explore the thing.....we'll see... Just a brief note..... Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ted Blank Subject: Re: FREE IS GOOD Date: Fri, 28 May 1999 15:40:47 -0700 (PDT) Also on the ADI site is the following: "Analog Devices Inc. announced today that it will supply its new micromachined accelerometer to Kinemetrics (www.kinemetrics.com), a leading supplier of seismic instrumentation. Utilizing Analog Devices' new ADXL202 iMEMS. motion sensor, Kinemetrics' MitiGator generates control signals at the onset of earthquakes for the automated shutdown of elevators, industrial machinery, transportation equipment etc." You can read the entire article at http://www.analog.com/publications/press/products/ADXL202_120898.html Ted Blank San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ken Navarre Subject: Field trip to Rock Creek (Tom's Place) Date: Sat, 29 May 1999 21:21:47 -0700 (PDT) On Thu, 27 May 1999, Bob Fryer wrote: > Thank you for the detailed explanation of ONE aspect of earthquake > sensitivity in animals. So Bob, did you ever take your trip to Mammoth last week??? Bobbie & I took a few days off work and made our way along the Eastern Sierras last week. Since Tioga Pass thru Yosemite was still closed we took the long way around... thru Mojave. We spent a few days laying in the sun in the Owens Valley to swim and watch the jet fighters and listen to the pilots as they tried to blast one another out of the sky in dog fight training. Quite fun... Later we headed north to Rock Creek - about 4 miles west of Tom's Place (12 miles south of Mammoth Mtn.). If you look at the USGS data for the Eastern Sierra you will see that this about 3 miles east of "ground zero" for most of the recent EQ activity in this area. We spent 2 days there prowling around and relaxing. While we were there the largest event was a 2.8 but it was "feelable". We had several telemetry receivers tracking the USGS sensors until a lightning strike took 3 of them off the air... At least I assume that was what made them "go away". A bright flash in the sky, loud thunder, then nada on the receivers... This is a nice area to camp, fish, and seismo surf! If you feel the need to check it out I can recommend a few good sites in the East Fork Campground. Drop me an e-mail and I'll elaborate... We were planning to do some direction finding to find the sensor sites but ran short of time. The weather was fine and the telemetry gave us the opportunity to get real quiet and feel the ground shake whenever the alarms sounded. Without the benefit of the alerts we would have never noticed the events that were less than mag 3.0. As it was the 2.8 could easily have been confused with road traffic or a very brief sense of vertigo. the campgound where we stayed just opened that week. None of the campground managers or campers were in the area for the mag 5.6 (6.0) two saturdays ago. Now that tioga Pass is open this area is an easy 7.5 hours from the Bay Area. I'm thinking I'll build an easily transportable system for a quick response when there is another "biggie" in the area. Hey Larry, how's the work coming on a PCMCIA a/d interface? :) Regards; Ken Navarre _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Stephen & Kathy Subject: Re: Field trip to Rock Creek (Tom's Place) Date: Sat, 29 May 1999 23:00:41 -0700 Ken Navarre wrote: > > We were planning to do some direction finding to find the sensor sites > but ran short of time. The weather was fine and the telemetry gave us > the opportunity to get real quiet and feel the ground shake whenever the > alarms sounded. Without the benefit of the alerts we would have never > noticed the events that were less than mag 3.0. As it was the 2.8 could > easily have been confused with road traffic or a very brief sense of > vertigo. > Regards; > Ken Navarre > Would you mind elaborating a little on your telemetry and alarm system????? Thanks in advance. Stephen Mortensen about 150 mi N W of Mammoth lakes PSN # 55 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Norman Davis WB6SHI Subject: Re: Field trip to Rock Creek (Tom's Place) Date: Sun, 30 May 1999 06:49:54 -0700 >Hey Larry, how's the work coming on a PCMCIA a/d interface? :) > >Regards; >Ken Navarre Ken Don't know if you have tried the FFTDSP program. I use it for listening to those sensors and Meteor scatter. I have a link to it on my web page under the meteor subject. It uses the sound card input from your notebook. Works pritty good but doesn't like anything else running withit. Norman M. Davis WB6SHI Shingle springs, CA mailto:normd@............. http://www.directcon.net/normd/index.htm ICQ: 7192318 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Seisguy@....... Subject: L.A. gets jolted awake Date: Sun, 30 May 1999 10:33:13 EDT From the Tri-Net homepage, Mike/San Diego ************************************** 06:37 PDT, Sunday, May 30 A M3.4 quake was widely felt in the Los Angeles are at 5:15 am this morning. The epicenter was located 2 miles southwest of East Los Angeles. As of 6:30 am, there have been three aftershocks in the M2 range: a M2.9 at 5:20 am, a M2.1 at 5:21 am, and a M2.6 at 5:29 am. The M3.4 is not an aftershock of any recent larger quakes. As with any quake in California, there is only a small chance (about one out of twenty) that the quake could be a foreshock to a larger earthquake. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Seisguy@....... Subject: Re: Animals Sensitivity(slightly off topic) Date: Sun, 30 May 1999 10:57:01 EDT Belgrade zoo animals provide early bombing warning By Colin McIntyre BELGRADE, May 30 (Reuters) - The noise starts around half an hour before the bombs fall as the animals in Belgrade zoo pick up the sound of approaching planes and missiles, director Vuk Bojovic said. ``It's one of the strangest and most disturbing concerts you can hear anywhere,'' he said in an interview. ``It builds up in intensity as the planes approach -- only they can hear them, we can't -- and when the bombs start falling it's like a choir of the insane. Peacocks screaming, wolves howling, dogs barking, chimpanzees rattling their cages.'' ``I have made a record every hour of each day of when the animals start acting up. One day, when this craziness is over, I'd like to check it with reliable data on when the planes were flying.'' ``Someone could make a scientific study out of it.'' Bojovic said the zoo had been hard hit by NATO's air strikes campaign aimed at forcing Belgrade to accept an autonomy deal for Kosovo, particularly when the alliance attacked Belgrade's power system, and indirectly the water supply. ``I had 1,000 eggs of rare and endangered species incubating, some of them ready to hatch in a couple of days. They were all ruined. That's 1,000 lives lost.'' Meat in the zoo's freezer defrosted and went off, making it suitable only to scavengers like hyenas and vultures. Belgrade people donated meat out of their home freezers when the power went down, ``but most of it wasn't even fit for animals.'' The lack of water meant that some animals, particularly the hippos, were literally swimming in their excrement, he said. ``We had to give dirty drinking water to a lot of pretty delicate animals. We won't know the effects of that for two or three months,'' Bojovic said. While the zoo overlooks the confluence of two major rivers, the Danube and the Sava, both are heavily polluted by chemical and industrial waste. The nightly air strikes, with their accompaniment of heavy anti-aircraft fire lighting up the sky, has had other, possibly longer-lasting effects on many of the animals, the director said. Many of them aborted their young in the latter stages of pregnancy. Many birds abandoned their nests, leaving eggs to grow cold. ``If they ever lay again, I just wonder what they will do with them,'' he said. Even a snake aborted some 40 foetuses, apparently reacting to the heavy vibration shaking the ground as missiles hit targets nearby. The worst night the zoo can remember was when NATO hit an army headquarters only 600 metres (yards) away, with a huge detonation. ``The next day we found that some of the animals had killed their young,'' the director said. ``A female tiger killed two of her four three-day-old cubs, and the other two were so badly injured we couldn't save them.'' ``She had been a terrific mother until then, raising several litters without any problems. I can't say whether it was the detonation or the awful smell that accompanied the bombing. I personally think it was the detonation,'' he added. On the same night, an eagle owl killed all of its five young, and ate the smallest of them. ``It wasn't because she was hungry. I can only think it was fear.'' The most disturbing case was of the huge Bengal tiger, who began to chew his own paws. ``He was practically raised in my office. He trusted humans.'' Looking up into the sky, Bojovic said the constant stream of NATO war-planes, with their trails of polluting gases, threatened to disturb the migration of several species of birds that pass over the area every year. Some were heading north just as NATO's bombardment began. ``They have always used these corridors. I wonder whether they will ever do so again. I think fauna right across Europe and beyond will feel the affects of this war for a long time to come.'' The grimmest spinoff of the war, now in its third month, is the sight of armed guards patrolling the zoo. ``They're not there to keep people from harming or stealing the animals,'' Bojovic said. ``Their job is to shoot the animals if the zoo gets bombed and some of them try and break out.'' 06:03 05-30-99 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: KACAMACHO@....... Subject: Re: Animals Sensitivity(slightly off topic) Date: Sun, 30 May 1999 16:34:53 EDT My heart bleeds for the crimes against nature that has occurred. In both animal and man alike. The worst possible scenarios have played out, and yet the politicians do nothing. They are bombing away a country, the culture and historical sites. They are erasing a way of life that will never be able to recover. Sure you can put back the buildings and the cars, but not the one of a kind treasures that can only be found in that region. Traumatizing the weak and vulnerable and victimizing lives of innocent beings that have the misfortune to be in harms way, with no way out. Make a study? We all know what that means. After all this is over, subject more innocent lives to tests and trauma. These people and animals have had enough, and who cares anyway, we all know animals are sensitive to the shock waves. Even some people. I am so sick of all this war and death. Politicians hold this region in their hands and they are so power thirsty. SHAME ON THEM. This is not meant as an attack, merely a vent and observation. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Bonnie Schafer" Subject: Re: L.A. gets jolted awake Date: Sun, 30 May 1999 19:19:27 -0700 Hi, well I didn't feel the 3.4 quake but my birds sure did and they got me out of bed--flipping all over their cages. I had to turn on the light and talk to them to calm them down. This brings up a question that I have and I know it is a really dumb one but a going to ask anyway. Do foreshocks have aftershock sequences of their own? For example, I know that there was a foreshock to the quake that occurred in 1933 on the Englewood Newport fault. Did this foreshock have aftershocks that decayed in a normal sequence as aftershocks would after any quake? Thanks for bearing with me in all of this. I really appreciate it. Bonnie the crafty crafter _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Tom Lambert Subject: Re: L.A. gets jolted awake Date: Mon, 31 May 1999 10:20:58 -0500 THANKS FOR THE INFO!---TOM LAMBERT. Seisguy@....... wrote: > >From the Tri-Net homepage, > > Mike/San Diego > ************************************** > 06:37 PDT, Sunday, May 30 > A M3.4 quake was widely felt in the Los Angeles are at 5:15 am this morning. > The epicenter was located 2 miles southwest of East Los Angeles. As of 6:30 > am, there have been three aftershocks in the M2 range: a M2.9 at 5:20 am, a > M2.1 at 5:21 am, and a M2.6 at 5:29 am. The M3.4 is not an aftershock of any > recent larger quakes. As with any quake in California, there is only a small > chance (about one out of twenty) that the quake could be a foreshock to a > larger earthquake. > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rex Klopfenstein, Jr." Subject: WINQUAKE PROBLEMS!! Date: Mon, 31 May 1999 14:13:47 -0400 I am have a little problem with Winquake. Here is my set up. I have two SG's connected to SDR on an old 486 running DOS (WIN95). This computer is connected to a WIN98 machine that is on my workbench in my basement via ethernet. I store all my data on a second hard drive on the WIN98 machine. I also have another WIN98 machine located in my office on the second story of my house. This too is connected to my network. I now can look at data without creating my own siesmic events in the basement. Everything seem to work fine. I have even created event files from my office. The first problem I have is that WinQuake (2.6.1) does not find the event files over the network. When I change the directory, I can't find the shared drive on my basement WIN98. I do find it when I view the Network Neighborhood. By the way, after I view with Network Neighborhood, the shared drive does appear on the WinQuake Directory dialog box. However, even with the proper directory listed in the Open File dialog box, the files still can't be opened! The second problem I have is that I get an error from my printer when I try to print a WinQuake plot. The printer gives an "out of memory" error and prints about 1/2 the page. I have a HP LaserJet 4L printer. I have never gotten this error before on any other document being printed. -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: Re: VBB driver circuit Date: Mon, 31 May 1999 16:28:39 -0500 (CDT) Brett, I finally had a chance to review your suggestions for modifications to the VBB seis feedback circuit with the additional amplifiers. I still haven't been able to get a complete copy of the .pdf text; the Netscape reader substitutes the font and trashes half the lines when I try to print it. (Suggestions?) It seems to me that you are trying to solve a problem with the long period response that is not a problem as long as the transfer function is determining the response as designed. I don't think you can solve the thermo-mechanical problems of the mechanism by modifying the basic response of the instrument to ground accelerations. The passive triple feedback is as ideal as can be for stability, no noise, and high dynamic range. THe major concern here, even if other problems didn't exist, is that having current amplifiers within the feedback limits the dynamic range to about 90 db, whereas it is greater than 160 db with the passive feedback. This is one of the primary virtues of a VBB seismometer. If you want to record the M 3.0 at 50 km without clipping while recording a M =5.0 at 30 degrees distance above the instrument noise, 140 db is needed (assuming that your digitizer is up to it). So I see no need to try to change the response at long periods. The transfer function shows a linear decrease in the velocity output that has a slope of omega^2. This means that for a 90 second instrument, the signal at the 12-hour earth tide (43000 seconds) is down by about 1000 from the flat output level. But it is still a real signal, and is recorded as an ULP signal by broadband digitizers that have a wide dynamic range. What you seem to be proposing to do is to make the slope of the low frequence response even steeper to reduce the effect of thermo-mechanical drift, earth tides etc.. I don't think that the current amplifier will actually accomplish this, so I don't see that it would gain anything. Although the transfer function can show a flat response with 100x Gn and 0.01x Cp (with other adjustments), it does not account for the nonlinearity (due to the non-zero output impedance) and phase shift of the added amplifiers and the inductance and back EMF of the coil that become part of the amplified feedback. The low feedback coil resistance Rf is not a problem as long as its generator constant is reasonable, like a Gn from 10 to 50 N/A. The output signal level (the constant k = M/(Cp*Gn)) is directly proportional to the Mass M and inversely proportinal to the feedback capacitor Cp and the coil constant Gn. If Gn is made too large, (in a tradeoff since with Cp constant it controls the high frequency response), the output is decreased, requiring additional amplification that reduces the dynamic range. But Rf controls the fourth order term, so if it is much more than 100 ohms, the short period response is unstable. I have previously (June 30 1998) discussed the subject of adding an amplifier between the junction of the triple feedback and the feedback coil input, and will repeat it below, with some editing. But first I have some related comments. Regarding the large capacitors, I have also previously discussed these to the point that electrolytics cannot and are not used for either the proportional feedback or the integrator C. Polypropolyne capacitors are used, and a 10 uf, 100 Volt unit costs about $3 in quantity from Mouser. Rex K. shows them in his drawings and parts lists of my latest schematics (which I have not had time to scan and post). Individually measured and used in parallel they provide the values needed, up to 40uf for a 320 second design. These are quite stable, noise free, passive elements of the circuit. I have had no problem with using them in parallel for large values. Regarding the high value resistances (eg 1608 megohms): 1000 megohms is pretty unreal: it is about the resistance of a 1mm square rod of pyrex glass 7 cm long. The highest commonly available resistance value is 22 megohms. However, since seismometers like to lurk in cold, dark, damp locations, where leakage can be a problem even with desiccation, circuit values of much greater than 2 megohms require careful implementation, like cleaning components with alcohol swabs after handling and the teflon sockets and ceramic standoff insulators that are used in commercial VBB systems. And a circuit with such a high resistance design value for feedback and to control the integration timing means that the capacitors and amplifiers involved must have at least 100 times higher resistance or input impedance. Most low noise amps (eg. OP-97) have 50 to 100 megohms differential input resistance; a FET input would be needed, with its associated problems, or a three-amp instrumentation configuration. I have no problem with a single 308A amp used as a non-inverting integrator with 2 megohms and 10 to 40 microfarads. The non-inverting integrator is stable and avoids the need to add an inverter to the differential/proportional side of the feedback. I don't see any problem with heating of the feedback coil; even at maximum output of the feedback resistor (15 volts into 500k, or 30 microamps, for example) the power is only 7.2 nanowatts. Regarding the amplifiers within the feedback: I must again emphasize that in the triple feedback VBB configuration the CURRENTS that flow through the force coil are controlled by the actual reactances of the three feedback elements, whose input is either the displacement voltage or the integral of it. These passive elements actually convert the mass displacement voltage into the characteristic current that shapes the acceleration response of their respective portion of the response curve. There can be no amplifier or other device between the summing junction of Rp, Cp, and RI and the force coil, since this would prevent these currents from flowing properly and in phase. Some experiments with a Norton, OTA (operational transconductance amplifier) or similar current amplifiers have been done, but the response is not linear (as expected from the transfer function), and has serious stability problems, possibly because of the non-linear low frequency phase response of the current amplifier. The transfer function actually describes an assembly of equations of accelerations that are produced by each characteristic feedback path. Another important point to notice is that the VBB output voltage is obtained from the displacement transducer output, which BECOMES the VBB output WHEN and ONLY when the triple feedback is functioning. This is a unique feature of this VBB circuit. Turn off the feedback, as when the boom needs to be recentered, and the output is that of an undamped mechanical sensor swinging freely at To. Re-connect the feedback, and the seismometer output immediately recovers as a VBB sensor with a period of Tn . Thus the output is not a function of the currents driving the feedback coil, but of the response of the mass to these accelerations as measured by the displacement detector. Also notice that the output always contains the DC displacement information, although at a much reduced level as mentioned above. The integrator output is actually the mass displacement value. I monitor it here, and use it when recentering with the centering motor, which is less than monthly even without the bi-metallic thermal compensator. Other force balance feedback configurations obtain a voltage function of acceleration across the force coil, and usually use an amplifier within the feedback loop, with the problem of limited dynamic range. This is not the case with this triple feedback configuration. As far as I know, none of the commercial VBB sensors have any amplifier within the feedback loop. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: RLLaney@....... Subject: 2nd Annual Colorado PSN meeting Date: Mon, 31 May 1999 18:18:39 EDT Meredith--I looked at your pictures of the PSN meeting on the web site this weekend. I found the pictures and text very interesting. Even picked up a couple of URL's to add to the collection. Many thanks for making it available to all. Bob Laney Herndon, VA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Steve Hammond Subject: Re: L.A. gets jolted awake Date: Tue, 01 Jun 1999 01:31:36 -0700 Hi Bonnie, This is a good question kuz I asked this one myself to one of the folks at the USGS. <<>> USGS Answer: Yes,foreshocks can have aftershocks. But to be a foreshock there must be a bigger event within the same rupture zone within some degree of time. My thoughts: Let's say that a 3.4 event takes place and then there are 12 aftershocks then nothing for 8 months and then a 7.5 hits the same spot-- At that point some bright grad student seismologist might write in the record, "the 7.5 was preceded by a 3.4 8-months earlier." No mention of the aftershocks need be made but they could be counted in the total number of foreshocks to the 7.5... This actually was the case in Loma Prieta. There was a 4.5 and it had a few aftershocks in the Los Gatos area 6 months or so before the main Loma Prieta event. Later, the event was cited as being a foreshock becasue it had taken place within the rupture zone. The question remains, how much time must past before an event becomes a foreshock to another larger event. Because of the time scale that events happen on (hundreds of years), applying the rule, a 6.5 in San Francisco could be a foreshock to an 8.5 5-10 years later if they both take place in the same rupture zone. Regards, Steve Hammond PSN San Jose Bonnie Schafer wrote: > Do foreshocks have aftershock sequences of their > own? For example, I know that there was a foreshock to the quake that > occurred in 1933 on the Englewood Newport fault. Did this foreshock have > aftershocks that decayed in a normal sequence as aftershocks would after any > quake? > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Bonnie Schafer" Subject: email problems Date: Mon, 31 May 1999 21:54:29 -0700 Hi, if anyone has sent me a message within the last couple of days would you please resend? I am having some email problems and am using two different programs to get my email and it is a little confusing at times. Thanks so much for doing this and am sorry to bother the list with this. Bonnie the crafty crafter _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Tom Lambert Subject: E-MAIL PROBLEMS Date: Tue, 01 Jun 1999 10:02:28 -0500 HI BONNIE, I HAVE PROBLEMS WITH MINE TOO , mine are definately program. TOM LAMBERTB > Hi, if anyone has sent me a message within the last couple of days would you > please resend? I am having some email problems and am using two different > programs to get my email and it is a little confusing at times. > > Thanks so much for doing this and am sorry to bother the list with this. > > Bonnie the crafty crafter > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rex Klopfenstein, Jr." Subject: WinQuake Problem: Printer Date: Tue, 01 Jun 1999 12:34:58 -0400 Larry: I finally got some time and did some playing. As I noted in my other post, I have an HP LaserJet 3L and I get printer error (out of memory). The printer is in the portrait mode as default. If I change to the landscape mode, the plot prints without errors. Possibly there is something wrong in the the printer interface routines in windows (the OnPrinter() or something like that if your using MFC & Visual C++). I have not had that problem with any other software, the image just gets scaled down and printed in portrait mode. I hope this helps!! Still haven't had time to do some serious playing with the network/shared drive access problem yet -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Re: VBB driver circuit Date: Tue, 01 Jun 1999 13:27:12 -0400 Sean-Thomas, At 04:28 PM 5/31/99 -0500, you wrote: >Brett, > >I finally had a chance to review your suggestions for modifications >to the VBB seis feedback circuit with the additional amplifiers. >I still haven't been able to get a complete copy of the .pdf text; >the Netscape reader substitutes the font and trashes half the lines >when I try to print it. (Suggestions?) When my Netscape won't display something properly, I can sometimes save it to a file, then close Netscape and then open the file with the appropriate program (the .PDF reader, in this case), and it will work OK. If you're still having problems, I'd be happy to send the file (40k+) directly to wherever you'd like. Will need a little more time to review the rest of your comments. Thanks for looking over my stuff. More later. Regards, Brett _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rex Klopfenstein, Jr." Subject: Siesm Questions?? Date: Tue, 01 Jun 1999 19:00:45 -0400 I finally have my two S-G siesmometer running and what appears to be adjusted and scaled. I have been trying to see how my system is working. I have just downloaded information on quakes from the NEIC webpage and using that information to 'request' an event file via SDR. I have just printed out the WinQuake plots and going to look at my results to see if I can see anything. I used the 'predicated' travel time to get me in the ballpark for request time period. Am I on the right track? I do have one question, I assume that the P-wave Shadow zone is the areas where the p waves are shadowed by internal structures in the Earth. I this right? -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "dave nelson" Subject: Re: Siesm Questions?? Date: Tue, 01 Jun 1999 17:17:14 PDT >I do have one question, I assume that the P-wave Shadow zone is the >areas where the p waves are shadowed by internal structures in the >Earth. I this right? >Rex Klopfenstein, Jr. Yes thats correct Rex, my book isnt handy bit from memory the shadow zone is between 103 and 130 (approx) degrees from the event some one is sure to correct me all my textbooks are back in new zealand Dave _______________________________________________________________ Get Free Email and Do More On The Web. Visit http://www.msn.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Bonnie Schafer" Subject: Re: E-MAIL PROBLEMS Date: Tue, 1 Jun 1999 20:24:39 -0700 Hi Tom, My problems seem to stem from the fact that AOL upgraded and Outlook and Outlook Express don't recognize these new codes. I guess steps are being taken to fix this problem but it is a real headache for me. Bonnie the crafty crafter _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Finke, John E." Subject: RE: Siesm Questions?? Date: Wed, 2 Jun 1999 09:45:38 -0400 I was under the impression that a shadow zone (region where no rays arrive) results as the ray (seismic wave path) can no longer "bottom out" and turn upward to travel through the earth eventually to be recorded on the earth's surface. In terms of Snell's Law and some calculus, this phenomena may written as the rate of change of the incidence angle (i) with respect to the change in path distance, r. The calculus enters as we look for values of maxima and minima; or by comparing the above relationship, the first derivative, to zero. Values of delta(i)/delta(r) > 0 imply that the ray has "bottomed" and is turning upward. Values of delta(i)/delta(r) < 0 imply that no maxima or minima has been reached and that the ray will not bottom out. There will be a range of the angle for which this is true and, of course, the angle of incidence and ray travel distance, hence the velocity will depend on the material properties ( bulk modulus and rigidity) encountered throughout the depths of the earth. John Finke, P.E., S.E. finke@........... St. Louis, MO > -----Original Message----- > From: dave nelson [SMTP:davenelson39@............ > Sent: Tuesday, June 01, 1999 7:17 PM > To: psn-l@.............. > Subject: Re: Siesm Questions?? > > > >I do have one question, I assume that the P-wave Shadow zone is the > >areas where the p waves are shadowed by internal structures in the > >Earth. I this right? > >Rex Klopfenstein, Jr. > > > Yes thats correct Rex, my book isnt handy bit from memory the shadow > zone > is between 103 and 130 (approx) degrees from the event > some one is sure to correct me all my textbooks are back in new > zealand > > Dave > > > _______________________________________________________________ > Get Free Email and Do More On The Web. Visit http://www.msn.com > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: RE: Siesm Questions?? Date: Wed, 02 Jun 1999 08:04:31 -0700 (MST) On Wed, 2 Jun 1999, Finke, John E. wrote: > I was under the impression that a shadow zone (region where no rays arrive) > results as the ray (seismic wave path) can no longer "bottom out" and turn > upward to travel through the earth eventually to be recorded on the earth's > surface. In terms of Snell's Law and some calculus, this phenomena may > written as the rate of change of the incidence angle (i) with respect to the > change in path distance, r. The calculus enters as we look for values of > maxima and minima; or by comparing the above relationship, the first > derivative, to zero. Values of delta(i)/delta(r) > 0 imply that the ray has > "bottomed" and is turning upward. Values of delta(i)/delta(r) < 0 imply > that no maxima or minima has been reached and that the ray will not bottom > out. There will be a range of the angle for which this is true and, of > course, the angle of incidence and ray travel distance, hence the velocity > will depend on the material properties ( bulk modulus and rigidity) > encountered throughout the depths of the earth. An even simpler way to look at it is that the outer core has a much slower velocity compared to the lower mantle and inner core between which it is sandwiched which is due to the loss of the shear strength. Then use the idea that a direct wave (like a P-wave) will always travel the path that takes it the least amount of time (called Fermat's Principle in optics). Since the path through the outer core is not a least time path, then these waves are diffracted away from it and their energy goes either more straight through the inner core or are diffracted around the core-mantle boundary. These latter waves (called Pdiff) are still detectable and are very important to people studying the liquid outer core transition to a solid mantle; a zone called D". In this way, the shadow zone is not a true complete shadow, but makes the waves more hazy and their arrivals are slightly delayed from closer arrival trends. The change in P-wave velocity across this boundary is around 6 km/sec, which is a huge difference. The lower mantle P-waves reach velocities of up to 14.3 km/sec, the highest in the entire earth. This also makes this discontinuity easy to see in reflections (PcP, PcS, ScS, etc.), because the amount of reflected energy is related to the change in velocity. This is termed the acoustic "impedance" of the boundary. Anyways, that is probably more than I needed to say... John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: RLLaney@....... Subject: RE: Seism Questions?? Date: Wed, 2 Jun 1999 11:28:02 EDT This series of email messages have reminded me of a question I had shortly after the recent WinQuake update. I notice that if an event is closer than 11,896 km, WinQuake defaults to the teleseismic travel-time table and P and S wave arrival times can be calculated. If the event is more than 11,896 km away, WinQuake defaults to the IASP91 travel-time table and P and S arrival times can be calculated as well. How can true P and S arrivals be calculated using the IASP91 tables beyond 11,896 km?? I thought that if the event is farther away than 11,896 km the arrivals will be affected by the earth's core (refraction, reflection, etc.) and arrivals will be some modification of the P and S waves. Is the answer in the definition (labeling) of what the first and following arrivals really are using the IASP91 tables? Can anyone help me out here? Thanks. Bob Laney Herndon, VA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Re: VBB driver circuit Date: Wed, 02 Jun 1999 15:36:25 -0400 Sean-Thomas, Thanks for taking the time to look over my circuit. Your comments were quite helpful in allowing me to clarify some of my thinking on this. Please let me know if you're still having problems viewing the "driver2.pdf" file. If you are, I'm sure I can figure out some other way to get it to you. As you had noted, I am attempting to emulate the response of the original, published circuit. Cd=24.1 Rp=581k, Ri=107k, etc., etc., though the parameters can easily be adjusted to match any other PID design. At 04:28 PM 5/31/99 -0500, you wrote: >Brett, > >It seems to me that you are trying to solve a problem with the long >period response that is not a problem as long as the transfer function >is determining the response as designed. I don't think you can solve >the thermo-mechanical problems of the mechanism by modifying the basic >response of the instrument to ground accelerations. The passive triple >feedback is as ideal as can be for stability, no noise, and high dynamic >range. > >THe major concern here, even if other problems didn't exist, is that >having current amplifiers within the feedback limits the dynamic range >to about 90 db, whereas it is greater than 160 db with the passive feedback. Is your concern here that the current amp circuit would limit the max input velocity or that it would add noise to the low amplitude end? Either could affect the dynamic range. The proposed circuit slightly increases the max allowable velocity input at frequencies above about 8 Hz so, at least that, is in the direction which improves dynamic range. >So I see no need to try to change the response at long periods. The >transfer function shows a linear decrease in the velocity output that >has a slope of omega^2. This means that for a 90 second instrument, the >signal at the 12-hour earth tide (43000 seconds) is down by about 1000 >from the flat output level. Looking at your numbers, that's a frequency ratio of about 478:1, so I'd expect the velocity response, to be down by about 478^2 at 12hours or about 1/228,000. If it *did* have that omega^2 slope, I wouldn't have considered changing the integrator. My analysis says that (not counting the output hi-pass filter) the velocity response changes to omega^1 slope below about 0.0017 Hz. That implies that the 12hour velocity response would be down roughly to 1/1,900 of the mid-band value. More interesting to me, is when you look at that in terms of the acceleration/force response: At 0.011 Hz (90 sec) the response is about 25,500 V/N, whereas from DC to 0.0017Hz it is relatively flat at about 6,400 V/N. So at 1/43,000 Hz the force response is only down by a factor of about 4. I'd like to see a force response that approaches *zero* at DC. Another way of looking at what I was trying to do, was to incorporate a portion of the effect of the velocity-output hi-pass filter into the feedback loop (into the integrator). That way instead of just masking the effects of very slow forces on the mass, the loop would be actively resisting those forces, resisting them from moving the mass beyond the active range of the feedback circuit.. That, in turn would make it much less necessary to rebalance those slow force changes such as those caused by spring creep. >But it is still a real signal, and is recorded >as an ULP signal by broadband digitizers that have a wide dynamic range. > I don't think I want an ULP sensor. Everything I've seen says that the environmental control required for good results is well beyond anything I'd want to try for. Was afraid there would be too much to worry about in the way of frequent mechanical adjustments and running out of DC range. >What you seem to be proposing to do is to make the slope of the low >frequence response even steeper to reduce the effect of thermo-mechanical >drift, earth tides etc.. But--at the same time I was also planning to remove all or part of the output hi-pass filter. >I don't think that the current amplifier will >actually accomplish this, so I don't see that it would gain anything. >Although the transfer function can show a flat response with 100x Gn and >0.01x Cp (with other adjustments), it does not account for the nonlinearity >(due to the non-zero output impedance) and phase shift of the added amplifiers >and the inductance and back EMF of the coil that become part of the amplified >feedback. All of those effects, should be kept satisfactorily low by the design. If I have missed something, I'd be happy to look at any specific area that doesn't seem right. With regard to the current driver circuit, it provides exactly the instantaneous voltage needed to force the coil current to be 100x the input current, regardless of any back EMF's. > >The low feedback coil resistance Rf is not a problem as long as its generator >constant is reasonable, like a Gn from 10 to 50 N/A. The output signal >level (the constant k = M/(Cp*Gn)) is directly proportional to the Mass M >and inversely proportinal to the feedback capacitor Cp and the coil constant >Gn. If Gn is made too large, (in a tradeoff since with Cp constant it controls >the high frequency response), the output is decreased, requiring additional >amplification that reduces the dynamic range. But Rf controls the fourth >order term, so if it is much more than 100 ohms, the short period response >is unstable. Completely agree. Increasing Rf will tend to decrease loop feedback stability. Even 8 ohms is significant, though (obviously) not enough, by itself, to cause oscillation. When you sum the PID branches at a "zero" impedance point, such as the current driver input, Rf disappears from the equation. Other high freq. poles will then be less able to push the circuit over the edge into oscillation. i.e. the loop phase margin will be a little better. I think the present value of Gn is fine. If someone wanted to increase it, they'd then also have to reduce the gain of other parts of the loop to avoid undesirable changes. >I have previously (June 30 1998) discussed the subject of adding an amplifier >between the junction of the triple feedback and the feedback coil input, >and will repeat it below, with some editing. But first I have some related >comments. > >Regarding the large capacitors, I have also previously discussed these to the >point that electrolytics cannot and are not used for either the proportional >feedback or the integrator C. Polypropolyne capacitors are used, and >a 10 uf, 100 Volt unit costs about $3 in quantity from Mouser. Rex K. shows >them in his drawings and parts lists of my latest schematics (which I have >not had time to scan and post). Individually measured and used in parallel >they provide the values needed, up to 40uf for a 320 second design. >These are quite stable, noise free, passive elements of the circuit. >I have had no problem with using them in parallel for large values. > >Regarding the high value resistances (eg 1608 megohms): 1000 megohms >is pretty unreal: it is about the resistance of a 1mm square rod of >pyrex glass 7 cm long. My book says that should be about 5 x 10^7 megohms, and I think they use better materials than Pyrex for the cores of high value resistors. >The highest commonly available resistance value >is 22 megohms. Those are carbon comp., and I wouldn't suggest using them for any precision application, as their tempco, drift and noise are likely going to be a problem. A number of manufacturers make very high value Ruthenium Oxide film resistors which are much more stable. Their best standard tempco is about 100ppm/deg C, though on special order you could possibly do even better. I plan to look into what's involved in ordering small quantities. >However, since seismometers like to lurk in cold, dark, >damp locations, where leakage can be a problem even with desiccation, >circuit values of much greater than 2 megohms require careful implementation, >like cleaning components with alcohol swabs after handling and the teflon >sockets and ceramic standoff insulators that are used in commercial VBB >systems. I agree that you do have to handle and clean them carefully, but very simple techniques like guard rings can enormously improve their tolerance to contamination and humidity. And once the enclosure is closed up, they shouldn't be getting all that dirty. >And a circuit with such a high resistance design value for feedback and to >control the integration timing means that the capacitors and amplifiers >involved must have at least 100 times higher resistance or input impedance. And the capacitors are 100 times smaller capacitance. That was the tradeoff I wanted to make. >Most low noise amps (eg. OP-97) have 50 to 100 megohms differential input >resistance; a FET input would be needed, with its associated problems, The LM6041 that I was suggesting has a minimum spec of 10^7 meghoms input resistance, with correspondingly low input bias current (2fA) and current noise (0.2fA/sqrt Hz). >or a three-amp instrumentation configuration. I have no problem with >a single 308A amp used as a non-inverting integrator with 2 megohms and >10 to 40 microfarads. The non-inverting integrator is stable and avoids >the need to add an inverter to the differential/proportional side of the >feedback. No argument at all. It's just that then its pole would still be at 0.008 - 0.002 Hz rather than at zero, which was one of my main goals for the modified design. > >I don't see any problem with heating of the feedback coil; even at maximum >output of the feedback resistor (15 volts into 500k, or 30 microamps, >for example) the power is only 7.2 nanowatts. > I agree, though I'd like to raise that to 800 microwatts, by providing up to 10 mA drive current. Still shouldn't be a problem, even then. >Regarding the amplifiers within the feedback: >I must again emphasize that in the triple feedback VBB configuration >the CURRENTS that flow through the force coil are controlled by >the actual reactances of the three feedback elements, whose input >is either the displacement voltage or the integral of it. These >passive elements actually convert the mass displacement voltage into >the characteristic current that shapes the acceleration response of >their respective portion of the response curve. There can be no >amplifier or other device between the summing junction of Rp, Cp, >and RI and the force coil, since this would prevent these currents >from flowing properly and in phase. I believe that the circuit I've proposed has no adverse effect on the proper flowing of those currents. >Some experiments with a Norton, >OTA (operational transconductance amplifier) or similar current amplifiers >have been done, but the response is not linear (as expected from the >transfer function), and has serious stability problems, possibly because >of the non-linear low frequency phase response of the current amplifier. > >The transfer function actually describes an assembly of equations of >accelerations that are produced by each characteristic feedback path. >Another important point to notice is that the VBB output voltage is >obtained from the displacement transducer output, which BECOMES the >VBB output WHEN and ONLY when the triple feedback is functioning. >This is a unique feature of this VBB circuit. Turn off the feedback, >as when the boom needs to be recentered, and the output is that >of an undamped mechanical sensor swinging freely at To. Re-connect >the feedback, and the seismometer output immediately recovers as a >VBB sensor with a period of Tn . Thus the output is not a function >of the currents driving the feedback coil, but of the response of the >mass to these accelerations as measured by the displacement detector. > >Also notice that the output always contains the DC displacement >information, although at a much reduced level as mentioned above. >The integrator output is actually the mass displacement value. I monitor >it here, and use it when recentering with the centering motor, which >is less than monthly even without the bi-metallic thermal compensator. In the circuit I'd proposed, for re-balancing purposes, you would want look at the DC output of the integrator op-amp, which is a measure of the DC balancing force being applied to the mass (in the original circuit, at low frequencies, displacement was proportional to force). That voltage might occasionally need to be re-balanced to zero, though it would require about 0.1N of steady imbalance to put it out of range. With the proposed circuit, the DC mass position variation from center would always be extremely small. As a practical matter, you might never need to re-balance. In any case, I'd think you would want to do the balancing with the loop active. > >Other force balance feedback configurations obtain a voltage function >of acceleration across the force coil, and usually use an amplifier >within the feedback loop, with the problem of limited dynamic range. >This is not the case with this triple feedback configuration. As far >as I know, none of the commercial VBB sensors have any amplifier >within the feedback loop. > Doesn't the feedback loop include the mass position sensor, all its demodulation and amplification, and any amplifiers driving the triple feedback branches? Not sure I understand what is particularly special about just that segment of the loop which contains those three elements. Also, I'm pretty sure that any commercial sensor which spec's a velocity response having "two poles at zero", as many do, has to be getting one of them from an active integrator. Thanks for hearing me out. Brett _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: JIm Hannon Subject: Re: VBB driver circuit Date: Wed, 02 Jun 1999 17:53:02 -0500 Brett Nordgren wrote: > > >Regarding the high value resistances (eg 1608 megohms): 1000 megohms > >is pretty unreal: it is about the resistance of a 1mm square rod of > >pyrex glass 7 cm long. > > My book says that should be about 5 x 10^7 megohms, and I think they use > better materials than Pyrex for the cores of high value resistors. > > >The highest commonly available resistance value > >is 22 megohms. > > Those are carbon comp., and I wouldn't suggest using them for any precision > application, as their tempco, drift and noise are likely going to be a > problem. A number of manufacturers make very high value Ruthenium Oxide > film resistors which are much more stable. Their best standard tempco is > about 100ppm/deg C, though on special order you could possibly do even > better. I plan to look into what's involved in ordering small quantities. > > >However, since seismometers like to lurk in cold, dark, > >damp locations, where leakage can be a problem even with desiccation, > >circuit values of much greater than 2 megohms require careful implementation, > >like cleaning components with alcohol swabs after handling and the teflon > >sockets and ceramic standoff insulators that are used in commercial VBB > >systems. > > I agree that you do have to handle and clean them carefully, but very > simple techniques like guard rings can enormously improve their tolerance > to contamination and humidity. And once the enclosure is closed up, they > shouldn't be getting all that dirty. I would not attempt to use any resistance much higher than 100 Meg Ohms. There are some 1000 Meg resistors in my junk box. They are hermetically sealed in glass tubes about 2 inches long to provide a long enough leakage path. I also found some 300 Meg 2% resistors at the company junk store today. They are made by Vishay. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Re: VBB driver circuit Date: Wed, 02 Jun 1999 20:22:52 -0400 At 05:53 PM 6/2/99 -0500, you wrote: > >I would not attempt to use any resistance much higher than 100 Meg Ohms. >There are >some 1000 Meg resistors in my junk box. They are hermetically sealed in glass >tubes about 2 inches long to provide a long enough leakage path. I also found >some 300 Meg 2% resistors at the company junk store today. They are made by >Vishay. >-- >Jim Hannon >http://soli.inav.net/~jmhannon/ >42,11.90N 91,39.26W >WB0TXL Jim, Why not? As I recall, we used to use up to 10,000 Meg resistors in ionization chamber work and never had any particular problems, although you certainly did want to keep your finger prints off them. One of my jobs was to clean the insulators after replacing the 1mil tungsten wire electrodes (which were always breaking). Used 100% ethyl alcohol, though I recently saw anhydrous isopropyl alcohol being sold for the same purpose. The former required a special permit, or else you had to pay liquor tax on it. Guarding virtually eliminates surface leakage (the main problem) as an issue. If guarding is not a familiar concept, I'd be happy to go into some more detail. The manufacturers I have found so far for high value (> 22 Meg) resistors are: Caddock EBG Hi Meg IRC K & M Ohmcraft Ohmite RFE Victoreen Vishay Not all the manufacturers make parts with the right specs, (resistance value, low tempco, 1% tolerance, low noise, reasonable size, reasonable? price) but several appear to. Victoreen looks like they may have the most suitable parts, and it appears that some values might be kept in stock. It is possible to get away with lower resistor values by replacing the single resistor with a 3-resistor "T" circuit. The only problem with that is that the effects of input voltage drift in the integrator op amp are magnified, though that may not turn out to be large enough to be a significant issue. Regards, Brett _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Another test... Date: Sat, 05 Jun 1999 23:57:03 -0700 Sorry another test. -Larry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: Network / Printer Problems Date: Sun, 06 Jun 1999 12:34:50 -0700 HI Rex -- Here's my configuration of SDR / WinQuake: I have three computers, and I'll call them SDR, Desktop, and Laptop. The SDR computer resides in the garage and the other two in the house, all connected by a network cable. Winquake resides on the desktop and can be run from either the desktop or the laptop. On the desktop computer are the following subdirectories: c:\wq32 c:\wq32\sdr c:\wq32\request c:\wq32\archives There are others under WQ32, but I don't think they are important here. The SDR computer logs on to the desktop computer and maps the desktop's drive C as its own drive E with the NET USE command. In SDR, the Local Event File Directory (under F5) is E:\WQ32\SDR, and the Request Control File Directory is E:\WQ32\REQUEST. The Winquake.exe file is loaded only on the desktop computer, in the c:\wq32 directory. On the laptop is a c:\wq32 subdirectory which contains the following files: city.dat email.dat magcorr.dat network.dat phases.dat replay.dat report.dat station.dat C:\wq32 on the laptop also contains a subdirectory called EQ Reports On the laptop, the file winquake.ini resides in the windows subdirectory. Windows 95 on the laptop is set to map the C drive on the desktop computer as drive F. Reconnect at logon is checked. The laptop has a shortcut to winquake on the desktop computer: f:\Wq32\winqk32.exe. Double-clicking this shortcut will run winquake on the laptop. When winquake is run from the laptop, the following configuration options are set: 1. Under File|Replay settings..., the Winquake Request Directory is set to F:\wq32\request, for each channel. The SDR mapped drive is set to E. 2. Under File|Local Data Directory, the Local Data File Directory is set to c:\wq32\EQ Reports. Downloaded reports from the Internet are put into this subdirectory. With this configuration, Winquake runs on the laptop but Winquake.exe resides on the desktop. Replay requests from Winquake on the laptop put the request file on the desktop computer, and SDR responds by putting the event file on the desktop, where is is read by Winquake and displayed on the laptop screen. Event archives are stored on the desktop under subdirectory f:\wq32\archives, as seen on the laptop, which is really drive c: on the desktop. Clear as mud, eh? It's all a bit confusing. Please ask for more clarification if you need it. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: Network / Printer Problems Date: Sun, 06 Jun 1999 14:50:11 -0700 Hi Karl I was thinking of putting my SDR computer in the garage to minimize analog noise. What hardware and software are you using for the networking? Larry mentioned a setup but I accidently deleted the email. The SDR computer is set up for DOS only , which is ok for SDR. It's also a 386 for what it's worth. Regards Barry Karl Cunningham wrote: > HI Rex -- > > Here's my configuration of SDR / WinQuake: > > I have three computers, and I'll call them SDR, Desktop, and Laptop. The > SDR computer resides in the garage and the other two in the house, all > connected by a network cable. Winquake resides on the desktop and can be > run from either the desktop or the laptop. > snip--- > > Karl Cunningham > La Mesa, CA. > PSN Station #40 > karlc@....... > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: Network / Printer Problems Date: Sun, 06 Jun 1999 17:46:57 -0700 Hi Barry -- The SDR computer is a 486DX/2-66 running Windows 95 in "boot to dos" mode. The desktop computer is a pentium machine running Windows NT4. The network software is only that which comes with the operating systems. I think it is necessary to load on at least Windows 3.11 (if not Win95) to be able to do the networking from the dos prompt. I think the 386 should work ok. The network hardware are cheap ethernet cards that are <$15 at computer discout stores. I use a combination of 10base2 (RG-58 coax) and 10baseT (twisted-pair) cabling, but either will work just fine. The coax is easier to use because you don't need a hub to connect a number of computers together, but if any part of the network becomes interrupted, the whole thing doesn't work. Hubs are in the $25 range at discounters too, so the twisted pair cable is not bad either. (Actually, if you are just connecting two computers together, you can usually use 10baseT cable without a hub.) Make sure the cards you get support whichever cable you plan to use. The main challenge is to get the computers to talk to each other aside from SDR and Winquake. There are a lot of little details and doing it the first time can be a bit tricky. There are MANY resources on the web giving instructions, and I am glad to help where I can. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... At 02:50 PM 6/6/99 -0700, you wrote: >Hi Karl > I was thinking of putting my SDR computer in the garage to minimize analog >noise. What hardware and software are you using for the networking? Larry >mentioned a setup but I accidently deleted the email. The SDR computer is set >up for DOS only , which is ok for SDR. It's also a 386 for what it's worth. >Regards _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: Network / Printer Problems Date: Sun, 06 Jun 1999 19:18:18 -0700 I would suggest loading Win95 or Win98. Somewhere on the Microsoft web site is a networking package that will allow you to use DOS 6.?, but, I think you will find it easier to get it working with Win95/98. For network cards I use Novel NE2000 compatible boards. -Larry Cochrane Redwood City, PSN At 05:46 PM 6/6/99 -0700, you wrote: >Hi Barry -- > >The SDR computer is a 486DX/2-66 running Windows 95 in "boot to dos" mode. >The desktop computer is a pentium machine running Windows NT4. The network >software is only that which comes with the operating systems. I think it >is necessary to load on at least Windows 3.11 (if not Win95) to be able to >do the networking from the dos prompt. I think the 386 should work ok. > >The network hardware are cheap ethernet cards that are <$15 at computer >discout stores. I use a combination of 10base2 (RG-58 coax) and 10baseT >(twisted-pair) cabling, but either will work just fine. The coax is easier >to use because you don't need a hub to connect a number of computers >together, but if any part of the network becomes interrupted, the whole >thing doesn't work. Hubs are in the $25 range at discounters too, so the >twisted pair cable is not bad either. (Actually, if you are just >connecting two computers together, you can usually use 10baseT cable >without a hub.) Make sure the cards you get support whichever cable you >plan to use. > >The main challenge is to get the computers to talk to each other aside from >SDR and Winquake. There are a lot of little details and doing it the first >time can be a bit tricky. There are MANY resources on the web giving >instructions, and I am glad to help where I can. > >Karl Cunningham >La Mesa, CA. >PSN Station #40 >karlc@....... > > >At 02:50 PM 6/6/99 -0700, you wrote: >>Hi Karl >> I was thinking of putting my SDR computer in the garage to minimize >analog >>noise. What hardware and software are you using for the networking? Larry >>mentioned a setup but I accidently deleted the email. The SDR computer is >set >>up for DOS only , which is ok for SDR. It's also a 386 for what it's worth. >>Regards > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: bigquake email Date: Sun, 6 Jun 1999 21:59:28 -0500 (CDT) Rex, A way to get current info from the USGS on larger (greater than M = 5) quakes is to subcribe to the bigquake mail list. Send mail to: (I think this is current) majordomo@................... and put "subscribe bigquake" in the body of the message; leave the subject line blank. Usually within two or three hours of an event, (even on weekends), you will get a notice of anything larger than a 5, with time and location info, as well as a list of arrivals at stations worldwide. This latter is handy if you can learn the names of stations near you so you know where to look in your data. For example, WCI is located in southern Indiana, BLA is in Virginia, and HVD is in Mass. Check the USGS web site for a station map. For example, todays' M = 5.8 in Guatemela occurred at 07:08Z, which is 02:08 AM CDT, and was reported by NEIS at 08:30 Z, and emailed at 05:10 AM CDT. THe report listed arrivals at 120 stations. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Re: Network / Printer Problems Date: Sun, 06 Jun 1999 21:58:22 -0700 Karl Cunningham wrote: > The SDR computer is a 486DX/2-66 running Windows 95 in "boot to dos" mode. > The desktop computer is a pentium machine running Windows NT4. The network > software is only that which comes with the operating systems. I think it > is necessary to load on at least Windows 3.11 (if not Win95) to be able to > do the networking from the dos prompt. I think the 386 should work ok. DOS doesn't come with any built in networking. The network from a DOS prompt has some limitation that it only works with either IPX/SPX or Netbeui? I can't remember which. Any way I know that it doesn't work with pure TCP/IP from experience. Windows for Workgroups comes with some network software, but you have to download TCP/IP from the MS website. I know I'm obsessed with TCP/IP. It's only going to be a bigger problem when we all try to switch over to IPv6 (Linux already can :)). If your SDR computer or any other computer has PCI you can get Netgear FA-310 TX network cards for <$30 from CDW. They have a lifetime warranty and they work with everything from 10baseT half duplex to 100baseT full duplex (you need a fast ethernet switch). They used to work under Linux with the DEC Tulip driver, but now they have to use a clone chip (Digital was bought by Compaq which also make network cards) so you have to use Netgear's included driver. I have a NE2000 clone also. The NE2000 clone is much slower over the same wire with a higher CPU load. How far can I pull the topic away from PSN and still remain somewhat relevant? ;) ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: Network / Printer Problems Date: Sun, 06 Jun 1999 22:42:12 -0700 At 09:58 PM 6/6/99 -0700,Greg wrote: > >DOS doesn't come with any built in networking. The network from a DOS >prompt has some limitation that it only works with either IPX/SPX or >Netbeui? I can't remember which. Any way I know that it doesn't work >with pure TCP/IP from experience. Windows for Workgroups comes with some >network software, but you have to download TCP/IP from the MS website. I >know I'm obsessed with TCP/IP. It's only going to be a bigger problem >when we all try to switch over to IPv6 (Linux already can :)). The networking between SDR and a Windows system uses Netbeui for drive mapping and not TCP/IP, so the DOS networking from Microsoft should work.... > >If your SDR computer or any other computer has PCI you can get Netgear >FA-310 TX network cards for <$30 from CDW. They have a lifetime warranty >and they work with everything from 10baseT half duplex to 100baseT full >duplex (you need a fast ethernet switch). They used to work under Linux >with the DEC Tulip driver, but now they have to use a clone chip >(Digital was bought by Compaq which also make network cards) so you have >to use Netgear's included driver. I have a NE2000 clone also. The NE2000 >clone is much slower over the same wire with a higher CPU load. Since only event files, usually under 100kbytes, are being transferred over the network a 100base T network is a little of an overkill... I recommend NE2000 type boards because I know they will work in the DOS mode networking with SDR. They may be slower but the board / driver does not interfere with the 1 ms interrupt from the A/D card needed for time keeping. -Larry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: angel rodriguez Subject: Re[2]: Network / Printer Problems Date: Mon, 7 Jun 1999 09:42:54 -0500 Hello Karl, I use a DOS only network Client which is free form Microsoft called MS Client and it works well and is easy to install. It uses NetBeui only but int ntegrates well with the W98 machine. I Best regards, Angel mailto:angel@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rex Klopfenstein, Jr." Subject: SDR Problem Date: Mon, 07 Jun 1999 12:36:14 -0400 Maybe someone out there can give me a clue of what I am doing wrong!! For the last three or four nights SDR has been hanging just after rolling over midnight and opening a new set of CHAN1,2,3,4 files. The files are created and last time stamp is 12:08AM. These files are 19KB. Once I restart the SDR computer, everything goes great until the next midnight rollover. My SDR computer is a 486/66 running WIN95 in DOS. This computer is linked with a WIN98 machine via network. I am running SDR 2.62. I have had the DEBUG MODE turned off, I just turned on to see if I get any messages. Any help would be greatly appreciated -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Re: Network / Printer Problems Date: Mon, 07 Jun 1999 11:27:56 -0700 Larry Cochrane wrote: > Since only event files, usually under 100kbytes, are being transferred over > the network a 100base T network is a little of an overkill... I recommend You can use 10 base T then. The cards automatically negotiate the highest speed the network is capable of. One thing I should pass on is that Windows 95 doesn't support fast ethernet over crossover cables. I just found that out. The same computer running Linux does. Why pay about the same money for something that may need replacing really soon? It's like buying a 386DX33 for $20 instead of buying a Pentium 133 for $35. Now that 10/100 hubs and switches have come down in price, it's not so critical. The difference was a lot more just a couple of years ago. Buy whatever you want. I like to think about the future too much. I guess I'm a hardware nut. You can't get ahold of the company that made MY NE2000 clone card. There's no mailing address, no company name, no phone number, no email address... Netgear has email and telephone support. Netgear is at http://netgear.baynetworks.com/ > NE2000 type boards because I know they will work in the DOS mode networking > with SDR. They may be slower but the board / driver does not interfere with > the 1 ms interrupt from the A/D card needed for time keeping. Well if the CPU load is less with the Netgear cards, I'd think that they would be less likely to interfere. That's just a guess though. I'll test my network with SDR and then we'll know for sure. This is going to be messy. The setup will be like this: P166 running Windows 95 in DOS mode (SDR computer) PII350 running Windows 95 in GUI mode (file server) Both computers have a Netgear card with a 10 base T hub in between. I'll report to the list with my sucess/failure. ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Nick & Sophie Caporossi Subject: Pc anywhere? And Y2K? Date: Mon, 07 Jun 1999 14:59:13 -0400 To the group: Thanks to those that have helped me in setting up the stations. The system is working very well. Is anyone using Pc anywhere? Am starting to set up some remote seismic sites using "pcANNYWHERE", I am using it on remote sites as "DOS Remote Hosts". It works quite well. A dedicated phone line is assigned to a computer that has SDR installed on it. The sensors are close by. It can also be used in Windows. The read me files and the Online support are easy to follow. Updating the Autoexec.bat took a little doing to get it be call waiting and having SDR running at the same time. If anyone wants a copy of the "Autoexec.bat" will be glad to post it to the PSN-L group. Using the transfer file command is all that is needed to upload a days data or an event. The gold is to install the software on the family's computers so that I will be but a phone call away. I think the subject of Y2K and how it will effect Sdr has been brought up once before but I don't recall what answer was. Will we have to reinstall SDR? Thanks again Nick (NAC,NC2) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: R: Pc anywhere? And Y2K? Date: Mon, 7 Jun 1999 22:21:03 +0200 Please, Nick send me your autoexec.bat. I use pcAnywhere from many times and it's seems to work very well until = now. Regards Francesco frnucer@......... =FF=FE<=00!=00D=00O=00C=00T=00Y=00P=00E=00 =00H=00T=00M=00L=00 = =00P=00U=00B=00L=00I=00C=00 = =00"=00-=00/=00/=00W=003=00C=00/=00/=00D=00T=00D=00 =00H=00T=00M=00L=00 = =004=00.=000=00 = =00T=00r=00a=00n=00s=00i=00t=00i=00o=00n=00a=00l=00/=00/=00E=00N=00"=00>=00= =0D=00=0A= =00<=00H=00T=00M=00L=00>=00<=00H=00E=00A=00D=00>=00=0D=00=0A= =00<=00M=00E=00T=00A=00 = =00c=00o=00n=00t=00e=00n=00t=00=3D=00"=00t=00e=00x=00t=00/=00h=00t=00m=00= l=00;=00 = =00c=00h=00a=00r=00s=00e=00t=00=3D=00u=00n=00i=00c=00o=00d=00e=00"=00 = =00h=00t=00t=00p=00-=00e=00q=00u=00i=00v=00=3D=00C=00o=00n=00t=00e=00n=00= t=00-=00T=00y=00p=00e=00>=00=0D=00=0A= =00<=00M=00E=00T=00A=00 = =00c=00o=00n=00t=00e=00n=00t=00=3D=00"=00M=00S=00H=00T=00M=00L=00 = =005=00.=000=000=00.=002=000=001=004=00.=002=001=000=00"=00 = =00n=00a=00m=00e=00=3D=00G=00E=00N=00E=00R=00A=00T=00O=00R=00>=00=0D=00=0A= =00<=00S=00T=00Y=00L=00E=00>=00<=00/=00S=00T=00Y=00L=00E=00>=00=0D=00=0A= =00<=00/=00H=00E=00A=00D=00>=00=0D=00=0A= =00<=00B=00O=00D=00Y=00 = =00b=00g=00C=00o=00l=00o=00r=00=3D=00#=00f=00f=00f=00f=00f=00f=00>=00=0D=00=0A= =00<=00D=00I=00V=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=002=00>=00P=00l=00e=00a=00s=00e=00,=00 = =00N=00i=00c=00k=00<=00/=00F=00O=00N=00T=00>=00<=00/=00D=00I=00V=00>=00=0D= =00=0A= =00<=00D=00I=00V=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=002=00>=00s=00e=00n=00d=00 =00m=00e=00 = =00y=00o=00u=00r=00 = =00a=00u=00t=00o=00e=00x=00e=00c=00.=00b=00a=00t=00.=00<=00/=00F=00O=00N=00= T=00>=00<=00/=00D=00I=00V=00>=00=0D=00=0A= =00<=00D=00I=00V=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=002=00>=00I=00 =00u=00s=00e=00 = =00p=00c=00A=00n=00y=00w=00h=00e=00r=00e=00 =00f=00r=00o=00m=00 = =00m=00a=00n=00y=00 =00t=00i=00m=00e=00s=00 =00a=00n=00d=00 = =00i=00t=00'=00s=00 =00s=00e=00e=00m=00s=00 =00t=00o=00 = =00w=00o=00r=00k=00 =00v=00e=00r=00y=00 =00=0D=00=0A= =00w=00e=00l=00l=00 =00u=00n=00t=00i=00l=00 = =00n=00o=00w=00.=00<=00/=00F=00O=00N=00T=00>=00<=00/=00D=00I=00V=00>=00=0D= =00=0A= =00<=00D=00I=00V=00>=00&=00n=00b=00s=00p=00;=00<=00/=00D=00I=00V=00>=00=0D= =00=0A= =00<=00D=00I=00V=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=002=00>=00R=00e=00g=00a=00r=00d=00s=00<=00/=00F=00= O=00N=00T=00>=00<=00/=00D=00I=00V=00>=00=0D=00=0A= =00<=00D=00I=00V=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=002=00>=00F=00r=00a=00n=00c=00e=00s=00c=00o=00<=00= /=00F=00O=00N=00T=00>=00<=00/=00D=00I=00V=00>=00=0D=00=0A= =00<=00D=00I=00V=00>=00&=00n=00b=00s=00p=00;=00<=00/=00D=00I=00V=00>=00=0D= =00=0A= =00<=00D=00I=00V=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=002=00>=00<=00A=00 = =00h=00r=00e=00f=00=3D=00"=00m=00a=00i=00l=00t=00o=00:=00f=00r=00n=00u=00= c=00e=00r=00@..........................."=00>=00f=00r=00n=00u=00c=00e=00r= =00@...........................<=00/=00A=00>=00 =00=0D=00=0A= =00<=00/=00F=00O=00N=00T=00>=00<=00/=00D=00I=00V=00>=00<=00/=00B=00O=00D=00= Y=00>=00<=00/=00H=00T=00M=00L=00>=00=0D=00=0A= =00 From: "Francesco" Subject: MS CLIENT Date: Mon, 7 Jun 1999 22:23:11 +0200 Where I can download the MS CLIENT for dos network? Which is the Microsoft web page? Francesco
Where I can download the MS CLIENT  for dos network?
Which is the Microsoft web page?
 
Francesco
From: angel rodriguez Subject: Re: MS CLIENT Date: Mon, 7 Jun 1999 16:48:25 -0500 Hello Francesco, Monday, June 07, 1999, 3:23:11 PM, you wrote: F> Where I can download the MS CLIENT for dos network? F> Which is the Microsoft web page? F> Francesco Hi, Here is a place to get MSClient in Italy. http://it.samba.org/samba/download.html There are also may other places in the world that have samba pages, just put Samba in a search engine. If I remember correctly what you get is the images of two disk which will install networking on DOS 3.3 and up. Best regards, Angel mailto:angel@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Wayne Abraham J73WA Subject: Moderate quake on Dominica Date: Tue, 08 Jun 1999 08:28:27 -0400 Hi all A moderat quake was felt here on Dominica. Preliminary reports from both amateur radio and the local radio stations indicate that it was felt over the entire island. My alarms went off and as soon as this thing stops recording, I will have the file posted on to Larry's server. I will post the BBL telemetered station first and will post the DM* station later this afternoon or this evening. Wayne -- Wayne Abraham 1430 Rodney Street Portsmouth, Dominica abrahamw@........ http://www.freeyellow.com/members6/dominicapsn/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: Moderate quake on Dominica Date: Tue, 08 Jun 1999 12:25:47 -0600 Wayne- I am very interested in seeing your .DMk records of this event. -Edward Wayne Abraham J73WA wrote: > Hi all > > A moderat quake was felt here on Dominica. Preliminary reports from both > amateur radio and the local radio stations indicate that it was felt > over the entire island. My alarms went off and as soon as this thing > stops recording, I will have the file posted on to Larry's server. I > will post the BBL telemetered station first and will post the DM* > station later this afternoon or this evening. > > Wayne > > -- > Wayne Abraham > 1430 Rodney Street > Portsmouth, Dominica > > abrahamw@........ > http://www.freeyellow.com/members6/dominicapsn/ > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Andre Charles (J73AC)" Subject: Re: Moderate quake on Dominica Date: Tue, 8 Jun 1999 20:17:31 -0400 Wayne I guess Ed will enjoy this one with much relish.And you will take this one in slices,so as not to choke on it!Ha ha ha Bon Appetit. -----Original Message----- From: Wayne Abraham J73WA To: PSN-L Mailing List Date: Tuesday, June 08, 1999 9:17 AM Subject: Moderate quake on Dominica >Hi all > >A moderat quake was felt here on Dominica. Preliminary reports from both >amateur radio and the local radio stations indicate that it was felt >over the entire island. My alarms went off and as soon as this thing >stops recording, I will have the file posted on to Larry's server. I >will post the BBL telemetered station first and will post the DM* >station later this afternoon or this evening. > >Wayne > >-- >Wayne Abraham >1430 Rodney Street >Portsmouth, Dominica > >abrahamw@........ >http://www.freeyellow.com/members6/dominicapsn/ > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Andre Charles (J73AC)" Subject: Re: Moderate quake on Dominica Date: Tue, 8 Jun 1999 20:23:07 -0400 Hi Ed I've fowarded the files to Wayne and they'll be with you in a while. Love to Jody and yourself,from Joyce the girls and I Andre' -----Original Message----- From: Edward Cranswick To: PSN-L Mailing List Date: Tuesday, June 08, 1999 3:27 PM Subject: Re: Moderate quake on Dominica >Wayne- > I am very interested in seeing your .DMk records of this event. >-Edward > >Wayne Abraham J73WA wrote: > >> Hi all >> >> A moderat quake was felt here on Dominica. Preliminary reports from both >> amateur radio and the local radio stations indicate that it was felt >> over the entire island. My alarms went off and as soon as this thing >> stops recording, I will have the file posted on to Larry's server. I >> will post the BBL telemetered station first and will post the DM* >> station later this afternoon or this evening. >> >> Wayne >> >> -- >> Wayne Abraham >> 1430 Rodney Street >> Portsmouth, Dominica >> >> abrahamw@........ >> http://www.freeyellow.com/members6/dominicapsn/ >> >> _____________________________________________________________________ >> >> Public Seismic Network Mailing List (PSN-L) >> >> To leave this list email listserver@.............. with the body of the >> message: leave PSN-L > >-- >Edward Cranswick Tel: 303-273-8609 >US Geological Survey, MS 966 Fax: 303-273-8600 >PO Box 25046, Federal Center cranswick@........ >Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". > > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: Pc anywhere? And Y2K? Date: Wed, 09 Jun 1999 01:43:42 -0700 At 02:59 PM 6/7/99 -0400, Nick Caporossi wrote: >Is anyone using Pc anywhere? >Am starting to set up some remote seismic sites using "pcANNYWHERE", I am >using it on remote sites as "DOS Remote Hosts". >It works quite well. A dedicated phone line is assigned to a computer that >has SDR installed on it. The sensors are close by. > It can also be used in Windows. The read me files and the Online support >are easy to follow. Updating the Autoexec.bat took a little doing to get it >be call waiting and having SDR running at the same time. If anyone wants a >copy of the "Autoexec.bat" will be glad to post it to the PSN-L group. >Using the transfer file command is all that is needed to upload a days data >or an event. > >The gold is to install the software on the family's computers so that I >will be but a phone call away. Great, let us know how it works out. It turns out that if you have the CD-ROM for PcAnywhere version 8 you also get the DOS version. I only discovered this a few days ago. I tried getting it to work on one of my test SDR systems using NetBIos. Unfortunately I was unable to get it working... I use the 32 bit version a lot. Its a great program. I use it to maintain several NT systems on the Internet. > >I think the subject of Y2K and how it will effect Sdr has been brought up >once before but I don't recall what answer was. Will we have to reinstall >SDR? Karl Cunningham did some Y2K testing last year on WinQuake and SDR. He found a few problems that I fixed, so current versions of both programs should work. If SDR is running on an older system you should check to make sure that the motherboard is Y2K compliant. This is a simple test. Set the time at the DOS prompt to Dec. 31 1999 23:58:00 and shutdown the system. Wait 5 minutes to make sure that the time as changed to Jan. 1 2000 and then power up system. At the DOS prompt check the time. A lot of older motherboards will show an incorrect time. The two SDR systems I have online are NOT Y2K ready. Today I bought a Y2K card that should fix the problem. Its a card that plugs into one of the ISA slots and it replaces the motherboards time functions. I haven't tested it yet, so I'm not sure if it works. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rex Klopfenstein, Jr." Subject: SDR Problems - Solved? Date: Wed, 09 Jun 1999 12:19:12 -0400 Larry- As you suggested, I reinstalled WIN95 on my 486/66 SDR machine with about 500MB boot partition and a second partition of about 1.6GB (drive is about 2.1GB). SDR made it through the night!! My original setup had three directories on the shared drive located on my WIN98 machine. One directory is for requests to create event files, one directory is for the created event files, and the third was for storing CHANx.jjj files. My SDR DOS machine was connected to the WIN98 (and shared drives) via a network connection. When I reconfigured my SDR machine as above, I moved the CHANx.jjj pointer to second partition on my SDR machine (from the shared network drive). If things seem stable, I will move the CHANx.jjj pointer back to my shared drive on my WIN98 machine, it makes it easy to check if SDR is running from my office. I also solve my WinQuake problem. WinQuake doesn't recognize the //Server notation, all worked fine when I mapped a network drive. I haven't really investigated my printer problem, but all works fine if I set to landscape mode. I have an older HP LaserJet 4L with only the memory it was shipped with. I tried to print some very large plot files (20 minutes with 50 SPS) in the portrait mode and received an 'out-of-memory' error from printer. You might want to add a note to your network setup notes for those who are not familiar with workings of Windows95. If using a plug-and-play network card, use the SYSTEM tab under the CONTROL PANEL to verify that the proper interrupt number and address is selected. I had to change my address and interrupt to match the IRQ=11,12, or 15 and ADDR of 300(hex). Make sure that the changes don't have a conflict. As you stated, the DOS mode driver for the network card will not work if these values are not adhered to. One final question, does SDR 2.62 have the GPS modification to accept the 1 pps signal in via DCD line of the RS232 interface. What is the actual pin # you designated for this input on the receptacle (DA9) on the rear of the computer? Thanks in advance -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: Used vertical sensor? Date: Wed, 9 Jun 1999 23:32:59 +0200 Hi, to all. I have found 4 good used geophones 4.5 hertz, thanks to Jim Croix, at Mitchum Ind. in Houston. Now I would like to find an used vertical 1 hertz seismograph, with a good price . Can someone help me? Francesco _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rex Klopfenstein, Jr." Subject: PSN-Want to Buy: RG316 Cable Date: Wed, 09 Jun 1999 19:24:02 -0400 I am building a GPS time source for my SDR system. I need about a foot of RG316 cable to connect my ONCORE card (via a MCX plug) to the chassis MCX connector I am incorporating into the enclosure. I have checked most of my sources and all they sell is 100' spools. Can anybody sell me a short piece of this wire? -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: RLLaney@....... Subject: Re: Reading Seismograms Date: Wed, 9 Jun 1999 20:01:43 EDT To all interested in this subject: Earlier this year Sean-Thomas Morrissey (March 12, 1999) and John Hernlund=20 (March 15, 1999) pointed out 4 publications on interpreting seismograms. I=20 don't recall follow-up description or discussion of these publications or ho= w=20 that they might be useful to amateurs interested in intrepreting seismograms= .. This afternoon I spent a few hours in the USGS library in Reston, VA=20 examining these publications, which are: 1) Anatomy of Seismograms by Ota Kulhanek Elsevier Science Publishing Company Inc., 1990 655, Avenue of the Americas New York, NY 10010 ISBN 0-444-88375-4 $142 at amazon.com 2) Principles Underlying the Interpretation of Seismograms by Frank Neumann U.S. Department of Commerce Special Publication 254, 1951 (out of print, but=20 a 1966 revision may be available according to the email from Sean Thomas) 3) Earthquake Interpretations-A Manual for Reading Seismograms by Ruth B.=20 Simon William Kaufmann, Inc., 1981 Los Altos, CA ISBN 0-913232-81-5 Out of print, but one could do a used book search on amazon.com or other=20 companies. 4) Broad Band Seismic Data Analysis by J.A. Carter Office of Nuclear Regulatory Research, U.S. Neclear Regulatory Commission,=20 1987 Series NUREG/CR; 4822 Not sure about availability. I did not read these publications from cover to cover, but I spent a good=20 part of the afternoon looking at tables of content, reading the purposes of=20 the publications and flipping through the pages looking at illustrations. =20 Therefore, my comments that follow are not "book reviews," but rather are=20 observations of an amateur interested in learning more about interpretation=20 of those squiggly lines we see on our event records, and which of the=20 publications I might like to have in my library. ANATOMY OF SEISMOGRAMS BY OTA KULHANEK Of the four publications this was the "pick of the litter." It was written=20 for the IASPEI/Unesco Working Group on the Manual of Seismogram=20 Interpretation (I looked in appropriate places in the publication and IASPEI=20 was never defined). The purpose of the report is to "=85.present a=20 comprehensive and tutorial manual for deciphering available seismograms=85..= " =20 The report is aimed at students in seismology, amateurs as well as more=20 experienced persons. It has virtually no mathematics, is easy to read, has=20 attractive illustrations and many examples of seismograms with phases=20 identified. The introductory text consists of Earthquakes Why and Where The= y=20 Occur, Structure of the Earth's Interior, Seismic Waves, Travel Times, and=20 Seismographs and Seismological Observatories. The remainder of the report=20 consists of interpretation of 55 plates showing various types events with=20 phases identified. If I were to pick one of the four, this would be the one= ..=20 The only problem with this one is the cost--$142.=20 PRINCIPLES UNDERLYING THE INTERPRETATION OF SEISMOGRAMS BY FRANK NEUMANN This report is designed for the interpretation of earthquake seismograms =20 "=85.to satisfy the requirements of a seismograph station director, the stud= ent=20 who is beginning his career as seismologist, or the amateur seismologist." =20 The report has good information in it, but its appearance comes across as a=20 dry 1950ish text book as compared to Anatomy of Seismograms, which by=20 comparison is "brighter" and easier to read. The report covers the necessar= y=20 background to understand seismographs and has 17 figures containing=20 seismograms. A number of the figures are fold-out type or in a pocket in=20 back. If this report were still in print, it would be good have in one's=20 library. EARTHQUAKE INTERPRETATIONS-A MANUAL FOR READING SEISMOGRAMS The author's purpose in this report is "=85.to help students interpret=20 seismograms, knowing that every wiggle on the records can eventually be=20 understood and explained." Of the report's 150 pages, 19 pages are=20 introductory information and procedures for beginners to interpret=20 seismograms. The remaining pages contain 45 seismograms, with phases=20 identified, and seismographs tables. Like the second report, this would be=20 good to have in the library. BROAD BAND SEISMIC DATA ANALYSIS This report describes the 3-component broad band digital seismic station SRN= Y=20 in Stone Ridge, New York. This is more an analysis of station performance=20 than a helpful guide to seismograph interpretation. But, it does have a=20 number of interpreted seismograms from the station. This one probably woul= d=20 not be on my buy list. I am under no illusion that just reading these reports would automatically=20 make anyone an expert seismic interpreter. But my casual review of the=20 reports makes me want to go back and read them in more detail to get a bette= r=20 understanding of "what the wiggles mean." I would appreciate hearing from anyone who has read and used these reports. =20 And are there other good sources of information to help interpret seismogram= s. Bob Laney Herndon, VA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Donald Sieber Subject: Re: Used vertical sensor? Date: Wed, 9 Jun 1999 23:16:09 -0700 At 11:32 PM 6/9/99 +0200, you wrote: >Hi, to all. >I have found 4 good used geophones 4.5 hertz, thanks to Jim Croix, at >Mitchum Ind. in Houston. >Now I would like to find an used vertical 1 hertz seismograph, with a good >price . >Can someone help me? > >Francesco > ------------------------------------------------------------------------- Francesco, I purchased one of these units several years ago and I recently sent in an order for another. However the order was delayed till the end of June because the supplier for the units is out of the country. Sincerely, Don Sieber -------------------------------------------------------------------------- From: rtclark@................ (R. T. Clark) Subject: Re: seismograph purchase Dear Don, Yes, we can provide you with another unit for the same price. L-4C, 1HTZ $ 375.00 NO CABLE, PLUS SHIPPING I CAN'T QUITE REMEMBER I THINK THE FREIGHT IS ABOUT $ 10.00 Please advise if we can provide you with any additional information. Kindest regards, CHRIS A. MILLER, VICE PRESIDENT THE R.T. CLARK COMPANIES, INC. P.O. BOX 20957 OKLAHOMA CITY, OK 73156 USA TELEPHONE: 405-751-9696 FAX: 405-751-6711 EMAIL: _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Giovanni Rotta" Subject: R: Used vertical sensor? Date: Thu, 10 Jun 1999 07:45:04 +0200 Te lo costruisco io per 50 mila lire !! Gio ---------- > Da: Francesco > A: PSN-L Mailing List > Oggetto: Used vertical sensor? > Data: mercoled=EC 9 giugno 1999 23.32 >=20 > Hi, to all. > I have found 4 good used geophones 4.5 hertz, thanks to Jim Croix, at > Mitchum Ind. in Houston. > Now I would like to find an used vertical 1 hertz seismograph, with a good > price . > Can someone help me? >=20 > Francesco >=20 >=20 > _____________________________________________________________________ >=20 > Public Seismic Network Mailing List (PSN-L) >=20 > To leave this list email listserver@.............. with the body of the= =20 > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: franuc@...... Subject: Re: Used vertical sensor? Date: Thu, 10 Jun 1999 14:35:11 +0200 Donald, tell me some information about this sensor. Type, price....etc. Thank you Francesco > At 11:32 PM 6/9/99 +0200, you wrote: > >Hi, to all. > >I have found 4 good used geophones 4.5 hertz, thanks to Jim Croix, at > >Mitchum Ind. in Houston. > >Now I would like to find an used vertical 1 hertz seismograph, with a go= od > >price . > >Can someone help me? > > > >Francesco > > > ------------------------------------------------------------------------- > Francesco, >=20 > I purchased one of these units several years ago and I recently > sent in an order for another. However the order was delayed till the > end of June because the supplier for the units is out of the country. >=20 > Sincerely, > Don Sieber > -------------------------------------------------------------------------- > From: rtclark@................ (R. T. Clark) > Subject: Re: seismograph purchase >=20 > Dear Don, >=20 > Yes, we can provide you with another unit for the same price. >=20 > L-4C, 1HTZ $ 375.00 > NO CABLE, PLUS SHIPPING >=20 > I CAN'T QUITE REMEMBER I THINK THE FREIGHT IS ABOUT $ 10.00 >=20 > Please advise if we can provide you with any additional information. >=20 > Kindest regards, > CHRIS A. MILLER, VICE PRESIDENT > THE R.T. CLARK COMPANIES, INC. > P.O. BOX 20957 > OKLAHOMA CITY, OK 73156 > USA > TELEPHONE: 405-751-9696 > FAX: 405-751-6711 > EMAIL: >=20 >=20 >=20 > _____________________________________________________________________ >=20 > Public Seismic Network Mailing List (PSN-L) >=20 > To leave this list email listserver@.............. with the body of the= =20 > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: Reading Seismograms Date: Thu, 10 Jun 1999 08:31:20 -0700 (MST) On Wed, 9 Jun 1999 RLLaney@....... wrote: > I would appreciate hearing from anyone who has read and used these reports. I encountered the first book at a library and read through it. It is a really nice introduction and does a great job helping someone to visualize wave ray paths and how they work in the earth. I think anyone who masters this book may be able to satisfy their thirst for skill in interpreting seismograms. > And are there other good sources of information to help interpret > seismograms. I think one of the more difficult things to introduce people to is how waves and other types of "signal processes" work and how their analysis can be simplified by a number of numerical tools. This kind of topic is not covered in the seismogram interpretation literature, but it is really important if somebody wants to gain more than just a qualitative understanding of the waves. The trick, however, is finding a good introduction into this stuff without encountering books packed with partial differential equations and tougher math concepts. Sean-Thomas may be able to recommend some good literature on this subject from the electrical engineering side of things (they use the same tools). The best introductory literature I have found on this kind of thing (data analysis and manipulation) are a series of books written by Jon Claerbout, one of the gurus of reflection seismology. What is really fantastic about his work is that it is also free on his web site! The address is: http://sepwww.stanford.edu/sep/prof/index.html This is a little more mathematical, but most of the material is just algebra and trigonometry (with complex numbers). I think his books give a great description of things like the FFT which everyone is probably curious about if they have been using it with Larry's Winquake software. Thanks for the "reviews" Bob! John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: Reading Seismograms Date: Thu, 10 Jun 1999 16:59:32 -0700 Thanks Bob for the great reviews. I added your email message to the Seismology Bibliography and Book Review web page at http://www.seismicnet.com/bibliography.html -Larry Cochrane Redwood City, PSN At 08:01 PM 6/9/99 EDT, you wrote: >To all interested in this subject: > >Earlier this year Sean-Thomas Morrissey (March 12, 1999) and John Hernlund >(March 15, 1999) pointed out 4 publications on interpreting seismograms. I >don't recall follow-up description or discussion of these publications or how >that they might be useful to amateurs interested in intrepreting seismograms. [snip] _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: More on Y2K and SDR Date: Thu, 10 Jun 1999 18:16:53 -0700 SDR User, This is from Karl about his Y2K testing last year. One thing I can do is place a year test in the function that deletes old files. The test would check the year supplied by the system and not delete any record files if it finds a date below say 1998. -Larry Cochrane Redwood City, PSN >Date: Wed, 09 Jun 1999 09:59:10 -0700 >To: cochrane@.............. >From: Karl Cunningham >Subject: Y2K > >Hi Larry -- >I remember during Y2K testing, my SDR computer wasn't Y2K compliant and >when it rolled over past 12/31/1999, SDR erased all the data it had saved >on the hard disk. I don't remember too well but I think the computer went >back to 1/1/1980 and SDR figured the data files were way out of date and >erased them. > >I do remember that if I turned my SDR computer off just before the >rollover, leave it off until after the rollover, turn it back on and set >the bios clock on bootup, then start SDR, everything worked ok. This is >what I plan to do on Dec 31. I really don't think it was an SDR problem >per se, and I don't remember if you changed SDR because of that or not. > >Anyway, if there is still a possibility of SDR erasing data during the Y2K >rollover on a non-compliant motherboard, it might do to mention it to >people using SDR. Also, since my SDR system is set to UTC, the rollover >will occur on 12/31 at 4PM local time. This is convenient since having to >stop and restart the system won't interfere with any Y2K festivities later >that night. > >-- Karl > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Alan & Jocelyn Munro Subject: Updating SDR problem Date: Fri, 11 Jun 1999 16:20:20 +1200 Hi all I have decided to update my version of SDR from 1.8 to 2.62 yet when I run the program it won't record any data. Program seems to run ok but no data. I am running the program on an old 486 33MHZ. Dave Nelson set the V1.8 for me but he's since left New Zealand. I must be doing something wrong anyone any ideas. thanks Alan Munro Invercargill NZ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: SDR Problems - Solved? Date: Fri, 11 Jun 1999 01:02:08 -0700 At 12:19 PM 6/9/99 -0400, you wrote: >Larry- > >As you suggested, I reinstalled WIN95 on my 486/66 SDR machine with >about 500MB boot partition and a second partition of about 1.6GB (drive >is about 2.1GB). SDR made it through the night!! Some background... I ask Rex in a private email about the size of the partition that SDR is running in. I read somewhere that 16 bit DOS programs (SDR is a 16 bit DOS program) can only access disks correctly if the partition is under 2GB. Looks like that is the case. I know that one of the system calls that gets the size of the disk can only return a number under 2.048 GB. >One final question, does SDR 2.62 have the GPS modification to accept >the 1 pps signal in via DCD line of the RS232 interface. What is the >actual pin # you designated for this input on the receptacle (DA9) on >the rear of the computer? Can't remember... If 2.62 supports it you will see the menu item "GPS 1PPS on RS232 DCB" under the F6 settings. If its not there let me know and I will send you version 2.3. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Arie Verveer Subject: Re: Pc anywhere? And Y2K? Date: Fri, 11 Jun 1999 19:58:22 +0800 Hi, I would be most interested in a copy of the Autoexec.bat file for "pcANNYWHERE". Nice solution to the remote problem, my seismometers are some 11 kilometre's away from home. - Arie Nick & Sophie Caporossi wrote: > > Am starting to set up some remote seismic sites using "pcANNYWHERE", I am > using it on remote sites as "DOS Remote Hosts". > > Updating the Autoexec.bat took a little doing to get it > be call waiting and having SDR running at the same time. If anyone wants a > copy of the "Autoexec.bat" will be glad to post it to the PSN-L group. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rex Klopfenstein, Jr." Subject: SG Card Date: Fri, 11 Jun 1999 12:23:09 -0400 I have a question on the operation of Larry's S-G board. There are two outputs: one high and one low. I have examined the schematics and came up with the following conclusions. The low output is filtered for a bandpass of about 0.017 Hz to 5 Hz and the high output is filtered for a bandpass of about 0.017 Hz to 10 Hz. Is this right? Also, I am wondering if someone can give some of the 'normal' background geological noise one will see. Most likely an 'east coast specialist' will have to answer this. It is my understanding that the east coast geology behaves differently than the west coast. I have my dual system up and running. I am now just trying to figure out the data I am recording. I still have to balance the outputs from the NS and EW S-G board. I plan to do this by looking a data for late at night and then try to adjust the channel gains to get somewhat equal output levels during a 'average' background noise period. I haven't found an event that I can identify unconditionally as real. I have identified the exploration of ed-the-cat, he has to check out everything in the house to make sure nothing has changed. -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Arie Verveer Subject: Re: More on Y2K and SDR Date: Sat, 12 Jun 1999 10:47:00 +0800 Hi, It probably been mentioned before but one simple solution to the Y2K problem, and the older non-compliant computers running SDR is to set the date to 1972 when we reach the year 2000. The calendar in 1972 is the same as the one in the year 2000. Maybe on the next release of Winquake we could have a field in which we could add a year to the date and hence all would be solved ? In 2001 the date would need to be set to 1990 and that would then be valid for another 2 years. I posted a list of compatible calendar dates on the 7th Jan 1999. Check the PSN archive. Just a idea for the non-gps systems. Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: angel rodriguez Subject: Re[2]: More on Y2K and SDR Date: Sat, 12 Jun 1999 04:39:13 -0500 Hello Arie, Friday, June 11, 1999, 9:47:00 PM, you wrote: AV> Hi, It probably been mentioned before but one simple solution to the AV> Y2K problem, and the older non-compliant computers running SDR is to AV> set the date to 1972 when we reach the year 2000. The calendar in 1972 AV> is the same as the one in the year 2000. AV> Maybe on the next release of Winquake we could have a field in which AV> we could add a year to the date and hence all would be solved ? AV> In 2001 the date would need to be set to 1990 and that would AV> then be valid for another 2 years. I posted a list of compatible AV> calendar dates on the 7th Jan 1999. Check the PSN archive. AV> Just a idea for the non-gps systems. AV> Arie AV> _____________________________________________________________________ AV> Public Seismic Network Mailing List (PSN-L) AV> To leave this list email listserver@.............. with the body of the AV> message: leave PSN-L Hi I've heard that there are some terminate and stay resident programs that sole the date issue on older computers of which I have two. Has anyone seen one of these TSR programs?? Angel _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: The Lahrs Subject: DaTaq DI150 Software Date: Sat, 12 Jun 1999 19:18:13 -0600 I found a bug in the wdq2psn and wdq2asc programs today. The data is from a 12-bit AD, but is stored in high 12 bits of 16-bit words. I was dividing the integer 16-bit number by 16 to get the "right" part but noticed that some of the detail of the trace were missing. Now I'm dividing by 8, but am not sure this is correct - doesn't sound right but the resulting trace looks better. The new versions are here: http://lahr.org/john-jan/psn/source_files/ Any suggestions would be welcome. John * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * AOL version of homepage: * * http://lahr.org/john-jan/homepage.html * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Arie Verveer Subject: Pointless but Fun Date: Sun, 13 Jun 1999 14:31:49 +0800 Hi, Happy 70,000 web page hits. I had to log on three times to see the web counter roll over! Waiting to see the 100,000'th rollover. Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Very local event... Date: Sun, 13 Jun 1999 02:35:13 -0700 Hi Everyone, A few hours ago this local event happened (from the local USGS finger server): 99/06/13 05:19:11 37.47N 122.27W 5.0 2.1MD A* 2 mi WSW of Redwood City, CA This is the first event I have seen with Redwood City as the reference point! This small event was about 4km from me and recorded very nicely with all of my sensor, even my strong motion FBA unit. This is the closes event I have recorded with my sensors. I have recorded 3 or 4 events near Woodside Ca., these events where about 7-9 km from me. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: pouellette Subject: Re: Very local event... Date: Sat, 12 Jun 1999 08:46:34 -0400 It was the sound of UPS dropping the ball on your shippment-again. Peter Larry Cochrane wrote: > Hi Everyone, > > A few hours ago this local event happened (from the local USGS finger server): > 99/06/13 05:19:11 37.47N 122.27W 5.0 2.1MD A* 2 mi WSW of Redwood > City, CA > > This is the first event I have seen with Redwood City as the reference > point! This small event was about 4km from me and recorded very nicely with > all of my sensor, even my strong motion FBA unit. This is the closes event > I have recorded with my sensors. I have recorded 3 or 4 events near > Woodside Ca., these events where about 7-9 km from me. > > -Larry Cochrane > Redwood City, PSN > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: Pointless but Fun Date: Sun, 13 Jun 1999 16:21:49 -0700 (MST) On Sun, 13 Jun 1999, Arie Verveer wrote: > Hi, Happy 70,000 web page hits. I had to log on three times > to see the web counter roll over! Waiting to see the 100,000'th > rollover. Time to start selling adviertising space??? :) John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "J. D. Cooley" Subject: I messed up Date: Sun, 13 Jun 1999 17:29:37 -0700 I just posted an event file for the M3.5 14mi NNW of Tehachapi. After looking at it on the web site, I notice that the times on the seismogram (and Org: line) are wrong. That was my first time at trying this. I'm sorry I messed it up. Don't really know what I did wrong. I will try to get it right next time. "JD" Poway, CA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "J. D. Cooley" Subject: Re: I messed up Date: Sun, 13 Jun 1999 17:49:07 -0700 Now I see what I did wrong. The event time should be 05:15:30 not 05:13:30. So sorry. "JD" At 05:29 PM 6/13/99 -0700, J. D. Cooley wrote: >I just posted an event file for the M3.5 14mi NNW of Tehachapi. After >looking at >it on the web site, I notice that the times on the seismogram (and Org: >line) are >wrong. That was my first time at trying this. I'm sorry I messed it up. >Don't >really know what I did wrong. > >I will try to get it right next time. > >"JD" >Poway, CA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: just a thought Date: Sun, 13 Jun 1999 18:33:35 -0700 Has anyone used dip switches for gain control on amps? It seems like it would be better than rotary switches in certain conditions. I wasn't sure about the quality of the contact wrt noise introduction. Regards Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Arie Verveer Subject: Re: just a thought - switches Date: Mon, 14 Jun 1999 11:55:01 +0800 Hi, I've used "mercury wetted" reed relays to switch the gain of an electrometer. It worked fine. The unit that switches the gain steps is located about 5 meters away from the electrometer. I think the reed contact resistance is about 0.1 ohms. Arie barry lotz wrote: > Has anyone used dip switches for gain control on amps? It seems like it > would be better than rotary switches in certain conditions. I wasn't > sure about the quality of the contact wrt noise introduction. > Regards > Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: robert barns <75612.2635@..............> Subject: Re: just a thought - switches Date: Mon, 14 Jun 1999 09:53:47 -0400 Arie, Good choice. Mercury wetted contacts can be pretty much guaranteed to = be noise-free forever. All other types can be noisy especially when vibrati= on is present or they corrode over a period of time. Mercury wetted contacts can also be relied on to give perfectly clean make and break--no "bounce". Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: just a thought - switches Date: Mon, 14 Jun 1999 10:41:44 -0700 Arie -- Dip switches are good so long as the contact resistance is low enough and stable enough for what you want to do. If you can, use ones with gold-plated contacts. Dip switches have the advantage that you can usually locate the switch close to the circuit being switched, which can reduce noise pickup. As people have suggested, mercury-wetted switches are good too. One problem with most switches is thermal emf's generated due to junctions of dissimilar metals. Some switches are much better than others, but it's doubtful that many dip switches are constructed with this in mind. The emf acts like temperature drift, but is really caused by the Seebeck Effect, which generates voltage due to temperature gradients and dissimilar metals in a circuit. Voltages of several tens of microvolts per degree C of gradient can be seen in some situations. The contact resistance problem can be licked by putting the switch in a "zero current" line -- i.e. an input to an op-amp. If you are changing gain on an op-amp stage, build a string of resistors and use the switch to select which tap of the string the op-amp's input is connected to. Putting a very high-value resistor from the op-amp output to the wiper of the switch will eliminate hitting the stops during switching. Solid-state analog switches (DG-xxx series, etc) are another good option. You can locate them close to the circuit being switched, control them remotely, contact resistance is predictable, most generate minimal thermal emf's, and they don't wear out. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Bonnie Schafer" Subject: Re: Busy day in California.... Date: Mon, 14 Jun 1999 20:37:25 -0700 Hi John, Nice to hear from you as it always is. I am behind in answering email because I have been out of town. Perhaps I shouldn't have used the word "predict" in my message concerning animals and their ability to sense an approaching quake. I have heard that birds are connected, somehow, to the magnetic field and they are very sensitive to it. I don't know about that but they do seem to react when a quake is about to happened. Of course, as you said, a Merriam of things can cause this and I sure haven't found any of my animals reliable enough to use them as "quake alarms" but the whole thing is rather interesting. In 1971 I didn't have birds but did have a black cat. She laid calmly on the bed even as the quake was occurring and didn't run under the bed until Mike and I headed for the bathroom doorway. Take care. Bonnie the crafty crafter _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: meredith lamb Subject: Strong signal coming in now... Date: Tue, 15 Jun 1999 14:57:16 -0600 Hi all, Strong signal coming in now. Where? Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: Strong signal coming in now... Date: Tue, 15 Jun 1999 14:12:57 -0700 CNN is reporting a strong EQ in Mexico. -Larry Cochrane At 02:57 PM 6/15/99 -0600, you wrote: >Hi all, > >Strong signal coming in now. Where? > >Meredith Lamb > > > > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: QUAKE IN PROGRESS Date: Tue, 15 Jun 1999 23:13:13 +0200 QUAKE IN PROGRESS LARGE S WAVE PROBABILY, GUERRERO, MEXICO 6.8 I.E.S.N ITALY _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Canie Brooks Subject: Re: Strong signal coming in now... Date: Tue, 15 Jun 1999 14:20:10 -0700 At 02:57 PM 6/15/99 -0600, meredith lamb wrote: >Hi all, > >Strong signal coming in now. Where? mexico ? > >Meredith Lamb > > > > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: R: Strong signal coming in now... Date: Tue, 15 Jun 1999 23:24:29 +0200 Strong eq in Mexico City. News from CNN and Italian Tv. No damnages Best view of the wave on USGS Live Ms 6.8 Francesco _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: MEXICO EQ Date: Tue, 15 Jun 1999 23:29:08 +0200 THIS IS THE REPORT BY NEIC 15Jun1999 20:42:01.4 18.3N 97.4W 33 MS=6.5 M*NEIC CENTRAL MEXICO _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: meredith lamb Subject: Re: Strong signal coming in now... Date: Tue, 15 Jun 1999 15:21:05 -0600 Larry Cochrane wrote: > CNN is reporting a strong EQ in Mexico. > > -Larry Cochrane > > At 02:57 PM 6/15/99 -0600, you wrote: > >Hi all, > > > >Strong signal coming in now. Where? > > > >Meredith Lamb > > > > Thanks Larry, Red Puma (Swiss) says: 20:42:039gmt 18.8n 97.2w depth 10, Mag 6.6 Central Mexico Suspect alot of damage around there. http://seismo.ethz.ch/redpuma/redpuma_ami_list.html Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Seisguy@....... Subject: Fwd: Strong Earthquake Rocks Mexico City Date: Tue, 15 Jun 1999 19:54:23 EDT Strong Earthquake Rocks Mexico City ..c The Associated Press By ISAAC A. LEVI MEXICO CITY (AP) - A strong earthquake shook a large swath of central Mexico today, killing at least one person, injuring hundreds, damaging historic buildings and sending tens of thousands of residents fleeing into the streets as buildings swayed. The first reports of significant damage of the quake, measured at a preliminary magnitude 6.7, were in the city of Puebla, about 60 miles east of Mexico City. One person died and many were wounded, said Dr. Alejandro Soto, director of the Puebla city Red Cross. Officials reported major damage to the 300-year-old city hall, a colonial-era church, a major highway bridge and other structures. Soto estimated about 200 were injured or hurt in the city, 10 seriously. He also said there were problems with telephone service in the area. The quake, which struck at 3:41 p.m. (4:41 p.m. EDT), was centered near Huajuapan de Leon, about 125 miles southeast of Mexico City and 80 miles south of Puebla, the National Seismological Service said. In some areas the quake reportedly rumbled for 40 seconds. It was ``felt very very strongly,'' said Hector Gonzalez, civil defense director of Huajuapan de Leon, a city of about 200,000 people. He said it knocked out electricity and telephone service, but he had no reports of injuries or major damage. President Ernesto Zedillo canceled a planned trip to the Caribbean coast and said he would fly to Puebla state to assess the damage. There no reports of injuries in the Mexican capital in the first hour after the quake and only scattered reports of damage. Telephone service and power were disrupted in some areas. In Cuernavaca, about 35 miles to the south of Mexico City, state civil defense director Arturo Sotelo said traffic lights were knocked out, causing some traffic accidents. He said electricity had been disrupted in at least 13 communities. Three cars were knocked across the street in front of the Guerrero state capital of Chilpancingo, about 115 miles south of Mexico City, said Gustavo Pina of the state civil defense agency. Streets in Mexico City were crowded with people fearful of returning to buildings. In Teposcolula, a few miles south of Huahuapan, the city hall partially collapsed, two houses fell and the main church was damaged, according to Sergio Hampshire, civil defense director for Oaxaca state, but there were no reports of injuries. In another town near Huahuapan, Tamazalupam de Progreso, officials said four students at a teaching college were hurt by shattering glass. Mexico's largest recent earthquake, on Sept. 19, 1985, was recorded at magnitude 8.1 and killed at least 6,000 people. Robert Meli, director of the National Center for Disaster Prevention, told local TV Azteca that Tuesday's quake was ``between five and 10 times smaller than the one in 1985.'' AP-NY-06-15-99 1859EDT Copyright 1999 The Associated Press. The information contained in the AP news report may not be published, broadcast, rewritten or otherwise distributed without prior written authority of The Associated Press. To edit your profile, go to keyword NewsProfiles . For all of today's news, go to keyword News. From: "Rex Klopfenstein, Jr." Subject: Central Mexico Quake Date: Tue, 15 Jun 1999 21:40:55 -0400 Well it looks like my seismo's work! I had an arrival time of 20:47:31 UTC. It looks good, Ann Arbor (approx 70 mi north) had an arrival time of 20:47:37 UTC. I haven't had an opportunity to check my WWW time setting. I would like to see some other east coast plots to see how mine compare. When I get some time I will post my plots and pictures of my setup. -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: The Lahrs Subject: DI-150 data scaling resolved Date: Tue, 15 Jun 1999 20:41:39 -0600 I asked Ken at DaTaq about the scaling of the data from the DI-150 AD unit. Per his response below I learned that if the sample rate is less than the maximum of 240 Hz (probably must be less than or equal 120 Hz) that the data is stored as 14-bit integers that are derived by averaging the samples. This is good news and solves the scaling mystery that I had with the conversion to ASCII and the conversion to PSN formats. The files wdq2psn.zip and wdq2asc.zip in http://lahr.org/john-jan/psn/source_files/ have been updated. Cheers, John >Return-Path: <70403.1462@..............> >Date: Tue, 15 Jun 1999 14:12:07 -0400 >From: Ken Spikowski <70403.1462@..............> >Subject: WWB32 scaling question >Sender: Ken Spikowski <70403.1462@..............> >To: The Lahrs >Content-Disposition: inline > >What you are missing is that fact that, when the DI-150 at 4800 baud is run >at less than 240 samples/sec, multiple 12-bit A/D converter readings are >averaged by the acquisition software and stored as left-justified 14-bit >values in the file. If you want to end up with integer counts instead of >A/D converter LSB's, you will have to calibrate the A/D range to +- 8192 >counts. > * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * AOL version of homepage: * * http://lahr.org/john-jan/homepage.html * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Plano Tx seismogram on the news Date: Tue, 15 Jun 1999 20:29:32 -0700 Greetings, I got a note from Geoff Fox of WTNH ABC/Connecticut asking if it was OK to show our seismograms on the air. I said sure no problem... The following link http://www.wtnh.com/weather/clips/forecast.ram shows a video clip of Geoff showing one of Bob Lewis's seismograms of the todays Mexico event. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: Plano Tx seismogram on the news Date: Tue, 15 Jun 1999 22:36:18 -0600 Bob & Larry- Congratulations! I have never before seen a more impressive exposition of a seismogram! -Edward Larry Cochrane wrote: > Greetings, > > I got a note from Geoff Fox of WTNH ABC/Connecticut asking if it was OK to show our seismograms on the air. I said sure no pr oblem... The following link http://www.wtnh.com/weather/clips/forecast.ram shows a video clip of Geoff showing one of Bob Lewis 's seismograms of the todays Mexico event. > > -Larry Cochrane > Redwood City, PSN > > _____________________________________________________________________ > Public Seismic Network Mailing List (PSN-L) > To leave this list email listserver@.............. with the body of the message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: JIm Hannon Subject: Re: DI-150 data scaling resolved Date: Wed, 16 Jun 1999 06:01:30 -0500 The Lahrs wrote: > I asked Ken at DaTaq about the scaling of the data from the DI-150 > AD unit. Per his response below I learned that if the sample rate > is less than the maximum of 240 Hz (probably must be less than or > equal 120 Hz) that the data is stored as 14-bit integers that > are derived by averaging the samples. This is good news and > solves the scaling mystery that I had with the conversion to > ASCII and the conversion to PSN formats. > > The files wdq2psn.zip and wdq2asc.zip in > http://lahr.org/john-jan/psn/source_files/ > have been updated. > Is the data averaged or just summed? Normally you would not have a larger number by averaging. So I suspect that the 12 bit numbers are summed into a 14 bit number. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "J. D. Cooley" Subject: Re: Central Mexico Quake Date: Wed, 16 Jun 1999 06:22:54 -0700 At 09:40 PM 6/15/99 -0400, Rex Klopfenstein, Jr. wrote: >Well it looks like my seismo's work! I had an arrival time of 20:47:31 >UTC. It looks good, Ann Arbor (approx 70 mi north) had an arrival time >of 20:47:37 UTC. I haven't had an opportunity to check my WWW time >setting. >I would like to see some other east coast plots to see how mine >compare. When I get some time I will post my plots and pictures of my >setup. > >-- >Rex Klopfenstein, Jr. >Bowling Green, OH >rklopfen@......... >www.wcnet.org/~rklopfen Rex, The USGS gives the following P arrival times. Don't know if this helps you or not. I would be glad to attempt to get the data from these stations and import it into WinQuake and send you the PSN format file. I don't want to post to the web page because there are enough of them there already for this quake. Let me know if you would like any/all of the 'grams from these sites (if I can get it). I just got home from working a 12-hour shift, so I'm too tired to check to see if I can get the data from these stations right now, but will try this afternoon. BINY Binghamton, NY 42.1993N 75.9861W 20:48:07.9 LBNH Lisbon, NH 44.2401N 71.9259W 20:48:39.6 LSCT Lakeside, CT 41.6784N 73.2244W 20:48:17.9 "JD" Poway, CA (San Diego County) jdcooley@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "J. D. Cooley" Subject: Re: Central Mexico Quake Date: Wed, 16 Jun 1999 06:45:49 -0700 At 09:40 PM 6/15/99 -0400, Rex Klopfenstein, Jr. wrote: >Well it looks like my seismo's work! I had an arrival time of 20:47:31 >UTC. It looks good, Ann Arbor (approx 70 mi north) had an arrival time >of 20:47:37 UTC. I haven't had an opportunity to check my WWW time >setting. >I would like to see some other east coast plots to see how mine >compare. When I get some time I will post my plots and pictures of my >setup. > >-- >Rex Klopfenstein, Jr. >Bowling Green, OH >rklopfen@......... >www.wcnet.org/~rklopfen Rex, I would say your time is right on the money. The US Census Bureau gives the lat/long for Bowling Green, OH as 41.37645N 83.64946W. Using that lat/long I used the USGS arrival time calculator and it gave the following: DATE-(UTC)-TIME LAT LON DEPTH MAG Q COMMENTS 99/06/15 20:42:06 18.41N 97.34W 79.6 6.7Mw A CENTRAL MEXICO =20 Expected 1s period body wave amplitude [ 2.68E+00 =B5m] [ 1.68E+01 =B5m/s] =20 delta azimuth (degrees clockwise from north) (deg) eq-to-station station-to-eq 25.72 24.2 211.2 travel arrival time # code time(s) dy hr mn sec 1 P 322.78 0 20 47 28 2 P 326.01 0 20 47 32 3 pP 341.08 0 20 47 47 4 pP 342.98 0 20 47 48 5 sP 350.73 0 20 47 56 6 sP 353.01 0 20 47 59 7 PnPn 363.71 0 20 48 9 8 PnPn 363.75 0 20 48 9 9 PcP 530.62 0 20 50 56 10 S 586.59 0 20 51 52 11 S 596.09 0 20 52 2 12 SPg 597.83 0 20 52 3 13 sS 619.04 0 20 52 25 14 sS 625.58 0 20 52 31 15 sSn 648.05 0 20 52 54 16 SnSn 650.68 0 20 52 56 17 ScP 742.74 0 20 54 28 18 PcS 751.44 0 20 54 37 19 ScS 972.20 0 20 58 18 20 PKiKP 990.65 0 20 58 36 21 pPKiKP 1013.24 0 20 58 59 22 sPKiKP 1021.85 0 20 59 7 23 SKiKP 1194.58 0 21 2 0 24 PKKPdf 1894.16 0 21 13 40 25 SKKPdf 2098.07 0 21 17 4 26 PKKSdf 2106.68 0 21 17 12 27 SKKSdf 2310.56 0 21 20 36 28 P'P'df 2403.16 0 21 22 9 29 P'P'ab 2532.44 0 21 24 18 30 S'S'df 3245.26 0 21 36 11 =20 Hope this helps you some. I would say that you are exactly correct with= your arrival time. "JD" Poway, CA (San Diego County) =20 > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the=20 >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rex Klopfenstein, Jr." Subject: Central Mexico Quake Plots Date: Wed, 16 Jun 1999 12:31:50 -0400 For those who are interested, I have posted the recording from my site for the Central Mexico quake yesterday. Any comments would greatly be appreciated! I will try to get some pictures of my S-G units on my website soon. -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Nick & Sophie Caporossi Subject: Re: Pc anywhere Autoexec.bat Date: Wed, 16 Jun 1999 14:19:37 -0400 At 07:58 PM 6/11/99 +0800, you wrote: >Hi, I would be most interested in a copy of the Autoexec.bat file for >"pcANNYWHERE". Nice solution to the remote problem, my >seismometers are some 11 kilometre's away from home. > >- Arie > Hi Arie: Sorry that I did not respond sooner. Was out of town for a week. The Pc anywhere worked quite well. We had a power failure while we were gone. When the power came back on the computer booted up and went right into Sdr. Autoexec is as follows: LH /L:0;1,45456 /S C:\DOS\SMARTDRV.EXE /X @ECHO OFF PROMPT $p$g PATH C:\DOS SET TEMP=C:\TENP C:\aw\aw /o:h /i:xxxxx /m:a cd sdr sdr.exe A point of caution the computer will be on call waiting at all times. so!!! A password is advisable. There are hackers out there that spend their time scanning phone lines for computer signals, and since it's public domain software it won't take much break in. Nick >Nick & Sophie Caporossi wrote: > >> >> Am starting to set up some remote seismic sites using "pcANNYWHERE", I am >> using it on remote sites as "DOS Remote Hosts". >> > >> Updating the Autoexec.bat took a little doing to get it >> be call waiting and having SDR running at the same time. If anyone wants a >> copy of the "Autoexec.bat" will be glad to post it to the PSN-L group. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Re: Plano Tx seismogram on the news Date: Wed, 16 Jun 1999 12:00:40 -0700 Larry Cochrane wrote: > I got a note from Geoff Fox of WTNH ABC/Connecticut asking if it was OK to show our seismograms on the air. I said sure no pr oblem... The following link http://www.wtnh.com/weather/clips/forecast.ram shows a video clip of Geoff showing one of Bob Lewis 's seismograms of the todays Mexico event. Dang. I missed it. I guess they don't keep yesterday's Real Video clips. anyway. ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: Plano Tx seismogram on the news Date: Wed, 16 Jun 1999 13:54:49 -0700 Geoff was nice enough to sent me a copy of the RealAudio file before it got overwritten. You can download the file from: ftp://ftp.drnet.com/users/psn/info/forecast.ra -Larry Cochrane Redwood City, PSN At 12:00 PM 6/16/99 -0700, you wrote: >Larry Cochrane wrote: > >> I got a note from Geoff Fox of WTNH ABC/Connecticut asking if it was OK to show our seismograms on the air. I said sure no problem... The following link http://www.wtnh.com/weather/clips/forecast.ram shows a video clip of Geoff showing one of Bob Lewis's seismograms of the todays Mexico event. > >Dang. I missed it. I guess they don't keep yesterday's Real Video clips. > > anyway. > >,Greg > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: [Fwd: Plano Tx seismogram on the news] Date: Wed, 16 Jun 1999 15:56:45 -0600 Larry- I sent this to Waverly Person, Director of the NEIC. -Edward Edward Cranswick wrote: > Waverly- > This is something I thought you might like to see. Yesterday's > Mexico earthquake was recorded by a Public Seismic Network (PSN) station > in Texas and somehow a Connecticut TV station got the record's image off > of a PSN website and presented it as an introduction to the nightly > weather report (only the 30 seconds is about the earthquake). The > weather guy dances around in front of a giant image of the seismogram > and talks about the P- and S-waves; it is quite impressive for a news > story. This is a ReadAudio video/audio clip, and you need a multimedia > PC to see/hear it. I meant to show this to you on my PC but > unfortunately my audio is on the fritz, and I figured that you or > someone upstairs might have a fully working multimedia system. If you > can't view this, please let me know and we will work out some way for > you to see it. I am interested in your opinion. > On a related note, we are slowly getting our act together about your > invitation to the PSN to submit phase data to the NEIC. Wayne Abraham of > the the Dominica PSN, Station PSDMA, has already submitted a P-arrival > time for last week's Windward Islands M5.5 event, and Bruce Presgrave > has included that in an interim solution: it is only 0.9 degrees away > and all the other stations are at least 6 degrees away. We are working > out a few more details on the PSN side about the submission procedure > and will come out with an "official" announcement on the PSN-L email > list in the next few days. > Thank you for your encouragement, advice, and help. > -Edward > > -- > Edward Cranswick Tel: 303-273-8609 > US Geological Survey, MS 966 Fax: 303-273-8600 > PO Box 25046, Federal Center cranswick@........ > Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". > > ------------------------------------------------------------------------ > > Subject: Re: Plano Tx seismogram on the news > Date: Wed, 16 Jun 1999 13:54:49 -0700 > From: Larry Cochrane > Reply-To: PSN-L Mailing List > To: PSN-L Mailing List > References: <3.0.3.32.19990615202932.00a90620@..............> > > Geoff was nice enough to sent me a copy of the RealAudio file before it got > overwritten. You can download the file from: > > ftp://ftp.drnet.com/users/psn/info/forecast.ra > > -Larry Cochrane > Redwood City, PSN > > At 12:00 PM 6/16/99 -0700, you wrote: > >Larry Cochrane wrote: > > > >> I got a note from Geoff Fox of WTNH ABC/Connecticut asking if it was OK > to show our seismograms on the air. I said sure no problem... The following > link http://www.wtnh.com/weather/clips/forecast.ram shows a video clip of > Geoff showing one of Bob Lewis's seismograms of the todays Mexico event. > > > >Dang. I missed it. I guess they don't keep yesterday's Real Video clips. > > > > anyway. > > > >,Greg > > > >_____________________________________________________________________ > > > >Public Seismic Network Mailing List (PSN-L) > > > >To leave this list email listserver@.............. with the body of the > >message: leave PSN-L > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: DI-150 data scaling resolved Date: Wed, 16 Jun 1999 21:20:51 -0700 Jim $0.02 The way I interpreted it was that by averaging several readings one would get a more accurate result (lower noise level) and therefore could resolve it to say 14 bits from 12. Regards Barry JIm Hannon wrote: > The Lahrs wrote: > > > I asked Ken at DaTaq about the scaling of the data from the DI-150 > > AD unit. Per his response below I learned that if the sample rate > > is less than the maximum of 240 Hz (probably must be less than or > > equal 120 Hz) that the data is stored as 14-bit integers that > > are derived by averaging the samples. This is good news and > > solves the scaling mystery that I had with the conversion to > > ASCII and the conversion to PSN formats. > > > > The files wdq2psn.zip and wdq2asc.zip in > > http://lahr.org/john-jan/psn/source_files/ > > have been updated. > > > > Is the data averaged or just summed? Normally you would not have a larger number > by averaging. So I suspect that the 12 bit numbers are summed into a 14 bit > number. > > -- > Jim Hannon > http://soli.inav.net/~jmhannon/ > 42,11.90N 91,39.26W > WB0TXL > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Seisguy@....... Subject: Fwd: Two Small Quakes Jolt L.A. Area Date: Thu, 17 Jun 1999 00:22:56 EDT Two Small Quakes Jolt L.A. Area ..c The Associated Press LOS ANGELES (AP) - Two small earthquakes rattled Los Angeles early Wednesday night, shaking downtown office buildings. There were no immediate reports of damage or injuries. The first earthquake had a preliminary magnitude of 3.1 and struck at 6:11 p.m., said Joe Frank, a seismologist with California Institute of Technology in Pasadena. The quake was centered three miles south-southeast of downtown. A 3.0-magnitude quake struck 40 seconds later in the same region two miles south-southeast of downtown. There were no reports of damage or injury, said Los Angeles Police Department Officer Eduardo Funes. ``It was a regular earthquake, nothing really alarming,'' said Funes from the downtown police headquarters. AP-NY-06-17-99 0018EDT Copyright 1999 The Associated Press. The information contained in the AP news report may not be published, broadcast, rewritten or otherwise distributed without prior written authority of The Associated Press. To edit your profile, go to keyword NewsProfiles . For all of today's news, go to keyword News. From: JIm Hannon Subject: Re: DI-150 data scaling resolved Date: Thu, 17 Jun 1999 05:47:48 -0500 barry lotz wrote: > Jim > $0.02 > The way I interpreted it was that by averaging several readings one would get a more > accurate result (lower noise level) and therefore could resolve it to say 14 bits > from 12. > Regards > Barry > Barry, That is correct. The problem comes in when one wants to operate a calibrated system. Just adding without dividing casuse the numbers to be larger and as John experienced caused confusion. One way this sort of problem is solved is to consider the binary number (however many bits of resolution) to always represent numbers from -0.999... to +0.999... In other words there is a binary point (decimal point) after the sign bit. In this system the significant bits are always shifted up to the MSB of the number. That way you can add usefull bits down at the LSB end without affecting the overall value of the number. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: The Lahrs Subject: Re: DI-150 data scaling resolved Date: Thu, 17 Jun 1999 05:38:17 -0600 Jim and Barry, Jim's $.02 were correct. If, for example you have a 12-bit digitizer, the range of values is -2048 to +2048. If four samples in a row are, say 10, 11, 11, and 11, then their average is 10.25. To represent this as an integer one can multiply by 4, so the value becomes 41. But then the range of values being recorded needs to be -8192 to +8192. This requires 4 times the number of possible numbers, or 14 instead of 12 bits. Of course this is overkill if you are averaging only two samples for each recorded value, and underkill if you're averaging more than 4 samples. Cheers, John * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * AOL version of homepage: * * http://lahr.org/john-jan/homepage.html * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: The Lahrs Subject: Correction! Date: Thu, 17 Jun 1999 05:40:57 -0600 No, that was Barry that had the right change! John * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * AOL version of homepage: * * http://lahr.org/john-jan/homepage.html * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: The Lahrs Subject: Mexico Quake Real Audio Date: Thu, 17 Jun 1999 06:30:39 -0600 I can't get through to: ftp://ftp.drnet.com/users/psn/info/forecast.ra Is that the correct URL? Thanks, John * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * AOL version of homepage: * * http://lahr.org/john-jan/homepage.html * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "James M Hannon" Subject: Re: Mexico Quake Real Audio Date: Thu, 17 Jun 1999 08:08:46 -0500 It works for me. I just loaded it and played it. Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Stephen & Kathy Subject: Re: DI-150 data scaling resolved Date: Thu, 17 Jun 1999 08:14:56 -0700 To the Dataq users, I converted about 16 minutes of the Central Mexico trace from my Dataq system into PSN format using John Lahrs wdq2psn program, found at: http://lahr.org/john-jan/psn/source_files/ and have to admit that I really enjoy being able to analyze my traces using Larrys WINQUAKE,, (until I can upgrade to Larrys board and GPS,, putting you on notice Larry). If you would like to see a gif of my first attempt,, (well, actually about the 6th attempt, it took me a couple of tries to figure it out),, you can find it at Bob Shannons alert page: http://www.silicon.net/~earth/alert.html click on the TRACES button! Thanks again to John Lahr for sharing his program,,, it works!!! Stephen Mortensen PSN Station #55 near Pilot Hill Ca _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: DI-150 data scaling resolved Date: Thu, 17 Jun 1999 08:37:44 -0700 (MST) On Thu, 17 Jun 1999, The Lahrs wrote: > Of course this is overkill if you are averaging only two > samples for each recorded value, and underkill if you're > averaging more than 4 samples. > Cheers, > John Right, and there is another phenomenon to be aware of when averaging (or in general "stacking") waveforms. We have a fellow here at ASU trying to obtain accurate seismograms inside a gas pressure vessel having two piezoelectrics situated at either end of a mineral which is sandwiched between two buffer rods. He is looking at P-wave velocities in hydrated minerals (such as talc) as pressure and temperature increases in order to make an analog for the upper portions of a subducting ocean slab. Because his measurements are inherently noisy he averages his waveforms to get a more accurate value and to reduce the noise. Some problems occur when some seismograms are slightly shifted in time. What happens is that what may have been a sharp first arrival becomes broadened in time and begins to look like a broad gaussian distribution. This makes picking the arrival time more difficult than it may have been to begin with, but also causes other problems too. This can be illustrated by making two synthetic signals such as: Signal 1: +00,+01,-02,-01,+01,+03,+00,-01,+05,+19,+45,+32,+14,-03 Signal 2: +01,-02,-01,+01,+03,+00,-01,+05,+19,+45,+32,+14,-03,-01 As you can see, signal 2 is shifted one unit of time to the left. The arrival can be picked fairly easily with the +05,+19,+45 progression in either one of the records. Now lets average them (rounding up): Average: +01,-01,-02,+00,+02,+02,-01,+02,+13,+32,+39,+23,+05,-02 As you can see, the arrival has a smaller amplitude (+39) than it did in either of the original seismograms (+45). Also, the arrival's front slope has been smoothed (reduced). If you do this many times you will find that the arrival becomes more and more indistinct. This is especially true when the two seismograms are not the exact same recording shifted in time. A possible and fairly simple solution for this is to perform a correlation on the seismograms. What a correlation does is to shift each record in time and for each shift average the products of the corresponding values in each time slot. If two seismograms are closely matched, then the correlation value for that time shift will be greatest. What you then do is choose one of your records as a reference and shift the other seismogram to the time value that matches it most closely using the correlation result. In the above example, the time shift of 1 unit in time will produce the largest correlation. So if you shift your seismograms using the correlation, then you can average more safely. Also, this correlated average can be used for other types of operations such as deconvolution with much more safety than just a straight average. Deconvolution is a numerical technique of removing the characteristics of your seismometer from an earthquake record to get a more accurate idea of the ground motion. If anyone would like to hear more about this technique, let me know and I can post a simple description. John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: The Lahrs Subject: Re:Mexico Quake Real Audio Date: Thu, 17 Jun 1999 12:21:23 -0600 I got the film clip just now. For some reason Netscape doesn't recognize the .ra file type and before, when I tried ftp from DOS I was using the wrong URL. It is a great clip - just wish the weatherman had mentioned that it came from the PSN! Cheers, John * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * AOL version of homepage: * * http://lahr.org/john-jan/homepage.html * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Submitting PSN data to NEIC Date: Thu, 17 Jun 1999 23:58:20 -0600 PSN members- One of the activities included in the 2nd Spring Colorado Public Seismic Network (PSN) Meeting at the USGS Golden, Colorado, on Friday 21 May was a tour of the National Earthquake Information Center (NEIC) conducted by the NEIC Director, Waverly Person. During the the tour, in response to a request relayed from Wayne Abraham of the Dominica PSN, Waverly said that the NEIC would welcome reliable P-wave picks (arrival times) of significant earthquakes from established PSN stations, e.g., see . Timing must be specified to 0.1 s, the precision of timing information in the PSN waveform file, and the seismograph A/D's should be synchronized to WWVB or GPS. Only submit those P-pick times that can be picked with an accuracy of +/- 0.1 s. Bruce Presgrave of the NEIC further specified that the PSN stations should be those that expect to be operating for at least a year and that the geographic coordinates of the station locations (latitude and longitude) should be specifed with a precision of at least three decimal places, i.e., 0.001 (one thousandth), of a degree (~ 100 m). To make the locations modern and consistent, the coordinates should be measured with respect to WGS84 datum (used by GPS). The station elevation above sea level should specified in meters with a precision of 10 m. For each pick, the NEIC needs a single time of a single phase arriving at a specific station, i.e., a unique location on the Earth, with a unique station name. The station name (code) will be five letters, i.e., 'PSnnn', the first two of which are 'PS' for PSN, and the last three 'nnn' refer to the 3-letter codes currently being used for PSN stations. These codes are in the map and database maintained by Dave Nelson and are also in the NSS compilation put together last year by Steve Hammond, PSN, at the request of Steve Malone, CNSS: . The 3-letter code must be spatially unique, in other words, if the station moves by more than 0.001 degree (100 m), it will need a new code. In general, we do not want to use data from stations that move. Some of these stations are actually using 2-letter codes to define the location and using the third letter to refer to some other attribute such as channel number or instrument. I suggest that for these stations, the third character should be a zero '0' to denote that the 3-letter (character) code refers to the location as distinguished from the attribute. Since there has been and continues to be some inconsistency of station-code use, we will have to formalize the 3-letter codes of those stations submitting data to NEIC. This will entail keeping a list of those specific stations and their corresponding coordinates. This is partially and implicitly accomplished by listserver software that Larry Cochrane uses to maintain the integrity of Redwood City PSN Website . The procedure for submitting PSN data via email to the NEIC is reviewed and explicitly specified in the included email (below) from Bruce Presgrave. PLEASE READ THIS NOTE CAREFULLY BEFORE SUBMITTING DATA TO THE NEIC AND PLEASE FOLLOW HIS INSTRUCTIONS PRECISELY; IF YOU HAVE QUESTIONS, PLEASE EMAIL: Edward Cranswick . Obviously, the NEIC maintains a station list and phase list of the data they use, but we, the PSN, also want to keep track of all the PSN data submitted to the NEIC. Therefore, please CC all email containing data submitted to NEIC to the PSN-L listserver and to Edward Cranswick . >From Bruce Presgrave, NEIC: > Hi Ed, > The first station of the PSN has been formally registered with an international > code, PSDMA as you suggested. I also entered the P-pick into the database > yesterday, but unfortunately, the final day for June 8 data for the QED was > Sunday, so it won't show up there, but it will be used in the PDE about 5 weeks > from now and as with all data received here for the QED/PDE program, it will > be sent on to the International Seismological Centre in the United Kingdon to > be included in their final Bulletins, about 2 years from now. In the meantime, > if you or Wayne Abraham would like to see an interim solution with the reading > included, let me know. > > I would like to confirm a few things we have discussed verbally: > > 1. All 5-character codes beginning with the letters "PS" (except for PSTOP, > which is "forbidden" because any word containing the characters STOP is > read by our parser as end-of-message) have been reserved for use by the PSN. > We assume that the PSN network will take care that each 3-letter code to > which we add the PS will be unique within the PSN network itself. > > 2. The procedure you used to get a new code registered was correct, and I > apologize for the delay getting it in, but I've entered about 50 new > stations in the past couple weeks, and the station registry is supposed to > be only a part-time task. To summarize the procedure, send the first > message with data (or a message BEFORE the first reading is sent is even > better) to me at caracara@................. with the information you gave > as in the example below: > > Station: PSDMA > Location: Soufriere, Dominica > Co-ordinates: 15.235N, 61.357W > Elevation: 60m > Owner: Wayne Abraham > E-mail: abrahamw@........ > > 3. Once the code is registered, the station owner can contribute readings as > often as they wish, by sending a message with the data to the address, > > neisdata@................ > > These data messages can simply be a single line, as follows: > > PSDMA Jun 15 P 18:22:02.1 > > or the operator can send multiple arrivals, including secondary phases, if > they wish, as shown below: > > PSDMA Jun 15 P 18:22:02.1 S 18:22:45.2 > Jun 16 P 19:01:23.56 > P 23:23:03.2 PcP 23:24:02.3 PP 23:25:10 S 23:29:01 > Jun 17 P 02:03:23.3 > > 4. Note that once the station is registered, data need not (and in fact, should > not) be sent to me, but to the neisdata account. That account is read > daily by the data entry personnel, to ensure that the data are processed > as quickly and as accurately as possible. Routine data messages are NOT > acknowledged (we process about 2,000 readings per day), but the station > operator can see how their data fit in the QED by looking at the webpage: > > http://wwwneic.cr.usgs.gov/neis/weekly/mchedrqed.dat > > Data from the PDE are available from our FTP site, as described in the > webpage: > > http://wwwneic.cr.usgs.gov/neis/data_services/ftp_files.html > > Thanks for your help getting this procedure set up. We look forward to getting > data from PSDMA and other PSN stations in the future. > > Best regards, > Bruce > We, the PSN, also look forward to our success in contributing valuable data to the world seismological community. Good luck! -Edward -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: Submitting PSN data to NEIC Date: Fri, 18 Jun 1999 00:41:13 -0600 PSN members- Another important factor in Waverly Person's request for PSN data was his conversation with Dave Wolney about some previous experiences that Dave had had in submitting data to the NEIC. -Edward > One of the activities included in the 2nd Spring Colorado Public Seismic > Network (PSN) Meeting at the USGS Golden, Colorado, on Friday 21 May was a > tour of the National Earthquake Information Center (NEIC) conducted by the > NEIC Director, Waverly Person. During the the tour, in response to a request > relayed from Wayne Abraham of the Dominica PSN, Waverly said that the NEIC > would welcome reliable P-wave picks (arrival times) of significant > earthquakes from established PSN stations, e.g., see > . -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: [Fwd: [Fwd: W. Colorado quake]] Date: Fri, 18 Jun 1999 01:13:36 -0600 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". Dave- I have sent out an email message, "Submitting PSN data to NEIC", that is largely a consequence of the conversation that you and Waverly Person had during the 2nd Spring Colorado PSN Meeting (please forgive my oversight in mentioning that in my original post). As you can see from the attached email from Bruce Presgrave, the NEIC would like your data in particular: the "Submitting PSN data to NEIC" email spells out how to do this. -Edward -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". From: Doug Crice Subject: Re: Submitting PSN data to NEIC Date: Fri, 18 Jun 1999 06:29:15 -0700 Apparently there is a little debate about the location of the Mexico earthquake. There was an article in the San Jose Mercury News about the differences between the location calculated by the USGS and one calculated by Mexico's seismologists. I guess every little seismograph helps. Here's a link to the article, which should be there for a few more days. http://www.mercurycenter.com/premium/world/docs/epicenter17.htm _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ted Blank Subject: RA file Date: Fri, 18 Jun 1999 08:57:57 -0700 (PDT) When I download the .ra file of the TV report, my RealAudio player says that it is not a RealAudio file. Is it a video file too? Ted Blank San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Canie Subject: Re: RA file Date: Fri, 18 Jun 1999 09:18:14 -0700 At 08:57 AM 6/18/99 -0700, you wrote: >When I download the .ra file of the TV report, my RealAudio player says >that it is not a RealAudio file. Is it a video file too? Yes it is. Canie > > >Ted Blank >San Jose, California > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: R: RA file Date: Fri, 18 Jun 1999 18:32:03 +0200 Yes, Ted It's a videoclip (.mpeg). Needs real player 4.0 or higher Francesco =FF=FE<=00!=00D=00O=00C=00T=00Y=00P=00E=00 =00H=00T=00M=00L=00 = =00P=00U=00B=00L=00I=00C=00 = =00"=00-=00/=00/=00W=003=00C=00/=00/=00D=00T=00D=00 =00H=00T=00M=00L=00 = =004=00.=000=00 = =00T=00r=00a=00n=00s=00i=00t=00i=00o=00n=00a=00l=00/=00/=00E=00N=00"=00>=00= =0D=00=0A= =00<=00H=00T=00M=00L=00>=00<=00H=00E=00A=00D=00>=00=0D=00=0A= =00<=00M=00E=00T=00A=00 = =00c=00o=00n=00t=00e=00n=00t=00=3D=00"=00t=00e=00x=00t=00/=00h=00t=00m=00= l=00;=00 = =00c=00h=00a=00r=00s=00e=00t=00=3D=00u=00n=00i=00c=00o=00d=00e=00"=00 = =00h=00t=00t=00p=00-=00e=00q=00u=00i=00v=00=3D=00C=00o=00n=00t=00e=00n=00= t=00-=00T=00y=00p=00e=00>=00=0D=00=0A= =00<=00M=00E=00T=00A=00 = =00c=00o=00n=00t=00e=00n=00t=00=3D=00"=00M=00S=00H=00T=00M=00L=00 = =005=00.=000=000=00.=002=000=001=004=00.=002=001=000=00"=00 = =00n=00a=00m=00e=00=3D=00G=00E=00N=00E=00R=00A=00T=00O=00R=00>=00=0D=00=0A= =00<=00S=00T=00Y=00L=00E=00>=00<=00/=00S=00T=00Y=00L=00E=00>=00=0D=00=0A= =00<=00/=00H=00E=00A=00D=00>=00=0D=00=0A= =00<=00B=00O=00D=00Y=00 = =00b=00g=00C=00o=00l=00o=00r=00=3D=00#=00f=00f=00f=00f=00f=00f=00>=00=0D=00=0A= =00<=00D=00I=00V=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=002=00>=00Y=00e=00s=00,=00 = =00T=00e=00d=00<=00/=00F=00O=00N=00T=00>=00<=00/=00D=00I=00V=00>=00=0D=00=0A= =00<=00D=00I=00V=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=002=00>=00I=00t=00'=00s=00 =00a=00 = =00v=00i=00d=00e=00o=00c=00l=00i=00p=00 = =00(=00.=00m=00p=00e=00g=00)=00.=00&=00n=00b=00s=00p=00;=00 = =00N=00e=00e=00d=00s=00 =00r=00e=00a=00l=00 =00p=00l=00a=00y=00e=00r=00 = =004=00.=000=00 =00o=00r=00 =00=0D=00=0A= =00h=00i=00g=00h=00e=00r=00<=00/=00F=00O=00N=00T=00>=00<=00/=00D=00I=00V=00= >=00=0D=00=0A= =00<=00D=00I=00V=00>=00&=00n=00b=00s=00p=00;=00<=00/=00D=00I=00V=00>=00=0D= =00=0A= =00<=00D=00I=00V=00>=00<=00F=00O=00N=00T=00 = =00s=00i=00z=00e=00=3D=002=00>=00F=00r=00a=00n=00c=00e=00s=00c=00o=00<=00= /=00F=00O=00N=00T=00>=00<=00/=00D=00I=00V=00>=00<=00/=00B=00O=00D=00Y=00>= =00<=00/=00H=00T=00M=00L=00>=00=0D=00=0A= =00 From: Karl Cunningham Subject: Re: Submitting PSN data to NEIC Date: Fri, 18 Jun 1999 09:50:27 -0700 Edward -- Thank you so much for your efforts in coordinating arrival-time data submission from PSN stations to the NEIC. I'm sure this will help us feel like a worthwhile contribution is coming from our hard work in developing our own systems. And for those of us who occasionally need it, a bit more justification in spending so much time on our stations. When you say significant earthquakes, could you give us some guidelines? I understand the need for additional data in areas where station coverage is sparse and that, in general, the more data the better. I do want to make a significant contribution, but don't want to unnecessarily clutter up the NEIC's computers. Something each of us should consider in this endeavor is time skew due to filtering. Most of the time analog filtering is applied to a signal, the resulting waveform is skewed in time, either ahead or behind. SDR has provision compensate for this by specifying a time offset for each channel, but this should be calibrated if the data is to remain accurate to 0.1s. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... At 11:58 PM 6/17/99 -0600, you wrote: >PSN members- > >One of the activities included in the 2nd Spring Colorado Public Seismic >Network (PSN) Meeting at the USGS Golden, Colorado, on Friday 21 May was a >tour of the National Earthquake Information Center (NEIC) conducted by the >NEIC Director, Waverly Person. During the the tour, in response to a request >relayed from Wayne Abraham of the Dominica PSN, Waverly said that the NEIC >would welcome reliable P-wave picks (arrival times) of significant >earthquakes from established PSN stations, e.g., see >. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: meredith lamb Subject: Re: Oxidizing leveling screws on a seismo base. Date: Fri, 18 Jun 1999 21:14:53 -0600 Hi all, Was successful in salvaging all adjustment screws, nuts, and the threaded holes on the vertical seismometer base, with Tap Magic, and a tap and die today. Have yet to obtain a screw lubricant. It was a bugger overall to do, but the die really helped removing the oxidation material. Thanks for all the help from all of you. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: Submitting PSN data to NEIC Date: Fri, 18 Jun 1999 20:21:01 -0700 (MST) On Fri, 18 Jun 1999, Doug Crice wrote: > Apparently there is a little debate about the location of the Mexico > earthquake. There was an article in the San Jose Mercury News about the > differences between the location calculated by the USGS and one > calculated by Mexico's seismologists. Who was closer??? > I guess every little seismograph helps. Here's a link to the article, which > should be there for a few more days. Do you have the different estimates? How far off are they? John Hernlund E-mail: hernlund@....... WWW: http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Doug Crice Subject: Re: Submitting PSN data to NEIC Date: Fri, 18 Jun 1999 20:36:53 -0700 All I know is what I read in the paper, which is a notoriously unreliable source. I was just featured in an article in the local paper where they continually referred to my ground penetrating radar as a "sonar". The article says the USGS and the Mexican were 50 miles apart on the epicenter, but they adjusted things down to only 17 miles horizontally and 13 miles difference on the depth. Actually, the disagreement doesn't seem like much to me, I just linked the article because of the recent discussion here about providing PSN arrival times to help resolve locations. If you missed the article the first time, it's at: web site http://www.mercurycenter.com/premium/world/docs/epicenter17.htm John Hernlund wrote: > > On Fri, 18 Jun 1999, Doug Crice wrote: > > Apparently there is a little debate about the location of the Mexico > > earthquake. There was an article in the San Jose Mercury News about the > > differences between the location calculated by the USGS and one > > calculated by Mexico's seismologists. > > Who was closer??? > > > I guess every little seismograph helps. Here's a link to the article, which > > should be there for a few more days. > > Do you have the different estimates? How far off are they? > > John Hernlund > E-mail: hernlund@....... > WWW: http://www.public.asu.edu/~hernlund/ > > ****************************************************************************** > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > -- Doug Crice web site http://www.georadar.com GeoRadar Inc. e-mail dcrice@............ 19623 Via Escuela Drive phone 408-867-3792 Saratoga, CA 95070 USA fax 408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: New WinQuake beta release From: Larry Cochrane Date: Sat, 19 Jun 1999 19:02:02 -0700 Greetings, Two weeks ago Barry Lotz report a problem with the Modify dialog box in WinQuake. The user could not save the magnitude or the depth. Sure enough there was a problem in the code... I release beta version 2.6.2 today fixing this problem. You can download the updated program at http://www.seismicnet.com/software.html. Please read the ReadMe file for info on how to upgrade to the new release. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Submitting PSN data to NEIC From: Edward Cranswick Date: Sun, 20 Jun 1999 21:40:44 -0600 Bob- I am in favor of using '0' as the third character, i.e., 'RL0', instead on a whole code, 'HER'. To remain consistent with data already submitted to the PSN, I thought that it would be easier to preserve the existing station identity as much as possible while at the same time explicitly specifying that a station code referred to a station location, and not an instrument. This is also consistent with a practice that we use with our portable seismographs. This is my suggestion. QED: Quick Epicenter Determination; near-realtime. PDE: Preliminary Determination of Epicenter; based on data within the few weeks. I will inquire as to what the exact current definitions of QED and PDE are and whether there is an NEIC station list available. -Edward RLLaney@....... wrote: > Hi Edward: > > Was pleased to see that the PSN people may be able to submit event data to > the NEIC. I have a few brief questions: > > The code for our unique station name, PSnnn--I have two sensors that I have > identified as RL1 and RL2 for use in the PSN listings. Do I understand you > correctly that for NEIC purposes I should use a zero for the third digit? > The unique location code would then be PSRL0? Would a code related to my > geographical location completely separate from my sensor identification be > more logical, e.g., PSHER for Herndon, VA? > > I know what QED stands for, but what is PDE? > > Is there a usgs site where one can look up the locations of the various > stations that are used by NEIC? > > Many thanks. > > Bob Laney > Herndon, VA -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Submitting PSN data to NEIC From: Edward Cranswick Date: Sun, 20 Jun 1999 21:47:25 -0600 Karl- Thank you for your comments. I think it is important that we, the PSN, try to make as good impression as possible with useful and reliable data. -Edward Karl Cunningham wrote: > Edward -- > > Thank you so much for your efforts in coordinating arrival-time data > submission from PSN stations to the NEIC. I'm sure this will help us feel > like a worthwhile contribution is coming from our hard work in developing > our own systems. And for those of us who occasionally need it, a bit more > justification in spending so much time on our stations. > > When you say significant earthquakes, could you give us some guidelines? I > understand the need for additional data in areas where station coverage is > sparse and that, in general, the more data the better. I do want to make a > significant contribution, but don't want to unnecessarily clutter up the > NEIC's computers. > > Something each of us should consider in this endeavor is time skew due to > filtering. Most of the time analog filtering is applied to a signal, the > resulting waveform is skewed in time, either ahead or behind. SDR has > provision compensate for this by specifying a time offset for each channel, > but this should be calibrated if the data is to remain accurate to 0.1s. > > Karl Cunningham > La Mesa, CA. > PSN station #40 > karlc@....... > > At 11:58 PM 6/17/99 -0600, you wrote: > >PSN members- > > > >One of the activities included in the 2nd Spring Colorado Public Seismic > >Network (PSN) Meeting at the USGS Golden, Colorado, on Friday 21 May was a > >tour of the National Earthquake Information Center (NEIC) conducted by the > >NEIC Director, Waverly Person. During the the tour, in response to a request > >relayed from Wayne Abraham of the Dominica PSN, Waverly said that the NEIC > >would welcome reliable P-wave picks (arrival times) of significant > >earthquakes from established PSN stations, e.g., see > >. > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Submitting PSN data to NEIC From: Wayne Abraham J73WA Date: Mon, 21 Jun 1999 00:30:47 -0400 Edward NEIC station list or station book is available at: http://gldss7.cr.usgs.gov/neis/station_book/station_book.html Wayne Edward Cranswick wrote: > Bob- > > I will inquire as to what the exact current definitions of QED and PDE are > and whether there is an NEIC station list available. > -Edward > > RLLaney@....... wrote: > > > Hi Edward: > > > > Was pleased to see that the PSN people may be able to submit event data to > > the NEIC. I have a few brief questions: > > > > The code for our unique station name, PSnnn--I have two sensors that I have > > identified as RL1 and RL2 for use in the PSN listings. Do I understand you > > correctly that for NEIC purposes I should use a zero for the third digit? > > The unique location code would then be PSRL0? Would a code related to my > > geographical location completely separate from my sensor identification be > > more logical, e.g., PSHER for Herndon, VA? > > > > I know what QED stands for, but what is PDE? > > > > Is there a usgs site where one can look up the locations of the various > > stations that are used by NEIC? > > > > Many thanks. > > > > Bob Laney > > Herndon, VA > > -- > Edward Cranswick Tel: 303-273-8609 > US Geological Survey, MS 966 Fax: 303-273-8600 > PO Box 25046, Federal Center cranswick@........ > Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Wayne Abraham 1430 Rodney Street Portsmouth, Dominica abrahamw@........ http://www.freeyellow.com/members6/dominicapsn/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Submitting PSN data to NEIC From: Wayne Abraham J73WA Date: Mon, 21 Jun 1999 00:36:21 -0400 Hi all I just checked the station book of the NEIC for the listing of PSDMA on Dominica and surely it is listed. It's listed among all the other stations on Dominica at: http://gldss7.cr.usgs.gov/neis/station_book/Dominica_REGION.html It is listed as being reported by PSNT or the PSN at:: http://gldss7.cr.usgs.gov/neis/station_book/PSNT_NETWORK.html Wayne -- Wayne Abraham 1430 Rodney Street Portsmouth, Dominica abrahamw@........ http://www.freeyellow.com/members6/dominicapsn/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: VBB Bridge From: "Rex Klopfenstein, Jr" Date: Mon, 21 Jun 1999 08:50:25 -0400 Sean I finally have finished other projects and have time to get back to the VBB. I have looked at your last email with comments on my schematics. As I said, I wanted to get things down the way you illustrated in your material. Then I will remove things I don't need. The first circuit that I am working on is the VRDT bridge. I will be mailing you a sketch of the bridge that I came up with that has the BRIDGE ZERO and ZERO TEST pots removed. Please check and email me your comments. Rex Klopfenstein, Jr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Navy warning technology From: Bob Fryer Date: Mon, 21 Jun 1999 16:42:01 -0700 Hi gang, This looks like a good bet for more information on how the Navy detects submarines -- and the signals which precede earthquakes. "Submarine Hunter" -- tonight on the Discovery Channel, 8 pm and again at 11, PDT. For the newcomers, the Dept of Defense admitted to Senator Alan Cranston that they did have the technology -- 25 years ago! Take care, Bob F ----- earthquake WARNING research ----- --- animals, people, scientific evidence --- --- http://www.teleport.com/~bfryer --- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Submitting PSN data to NEIC From: barry lotz Date: Sun, 20 Jun 1999 09:18:51 -0700 Ed Ditto. Well put Karl. Barry Karl Cunningham wrote: > Edward -- > > Thank you so much for your efforts in coordinating arrival-time data > submission from PSN stations to the NEIC. I'm sure this will help us feel > like a worthwhile contribution is coming from our hard work in developing > our own systems. And for those of us who occasionally need it, a bit more > justification in spending so much time on our stations. > > When you say significant earthquakes, could you give us some guidelines? I > understand the need for additional data in areas where station coverage is > sparse and that, in general, the more data the better. I do want to make a > significant contribution, but don't want to unnecessarily clutter up the > NEIC's computers. > > Something each of us should consider in this endeavor is time skew due to > filtering. Most of the time analog filtering is applied to a signal, the > resulting waveform is skewed in time, either ahead or behind. SDR has > provision compensate for this by specifying a time offset for each channel, > but this should be calibrated if the data is to remain accurate to 0.1s. > > Karl Cunningham > La Mesa, CA. > PSN station #40 > karlc@....... > > At 11:58 PM 6/17/99 -0600, you wrote: > >PSN members- > > > >One of the activities included in the 2nd Spring Colorado Public Seismic > >Network (PSN) Meeting at the USGS Golden, Colorado, on Friday 21 May was a > >tour of the National Earthquake Information Center (NEIC) conducted by the > >NEIC Director, Waverly Person. During the the tour, in response to a request > >relayed from Wayne Abraham of the Dominica PSN, Waverly said that the NEIC > >would welcome reliable P-wave picks (arrival times) of significant > >earthquakes from established PSN stations, e.g., see > >. > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Navy warning technology From: Bob Fryer Date: Tue, 22 Jun 1999 00:48:14 -0700 Hi gang, Well, the show title was not really consistent with the content. However, the first part demonstrated the reasons and attitudes that drive the naval services to jealously guard their technology. The show was about a British submarine, HMS Splendid, as she went through training to become the first British warship to fire a US Tomahawk cruise missle. Splendid was also the first British ship to fire on the United States since the Civil War -- the target was on San Clemente Island, CA. (;{)> In the second half of the program, a most interesting part of the training was the assignment to photograph the bottom of a (drifting) destroyer while not alerting it. They showed video tape of the bottom of the destroyer taken through the periscope from a distance of 10 _feet_! For additional related information, beyond my web page, I recommend "BLIND MAN'S BLUFF: The Untold Story of American Submarine Espionage," by Sherry Sontag and Christopher Drew. Take care, Bob F >-------------------------------------------------------------------------- > >Hi gang, > >This looks like a good bet for more information on how the Navy detects >submarines -- and the signals which precede earthquakes. > >"Submarine Hunter" -- tonight on the Discovery Channel, 8 pm and again at >11, PDT. > >For the newcomers, the Dept of Defense admitted to Senator Alan Cranston >that they did have the technology -- 25 years ago! ----- earthquake WARNING research ----- --- animals, people, scientific evidence --- --- http://www.teleport.com/~bfryer --- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: PSN Station Codes From: "Rex Klopfenstein, Jr" Date: Tue, 22 Jun 1999 09:24:41 -0400 Am I missing something! Is there a 'clearinghouse' for assignment of station codes? Is there a place (USGS) to find the allocated PSXX0 codes. I am thinking of picking PSBG0 as my station code. Any feedback would be appreciated Rex Klopfenstein, Jr Bowling Green, OH _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: PSN Station Codes From: Greg Date: Tue, 22 Jun 1999 10:02:19 -0700 If nobody else wants too, I can be the coordinator. Buelller? Bueller? Bueller? Okey dokey? Should we have a vote or something? Motion to burn Greg at the stake? Should the station ID numbers be somewhat private or on a web page? I have more than enough server space for a web page. Should it be first come, first served? Or maybe a battle to the death? ,Greg "Rex Klopfenstein, Jr" wrote: > > Am I missing something! Is there a 'clearinghouse' for assignment of > station codes? Is there a place (USGS) to find the allocated PSXX0 > codes. I am thinking of picking PSBG0 as my station code. > > Any feedback would be appreciated > > Rex Klopfenstein, Jr > Bowling Green, OH _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: SHOW! From: Tom Lambert Date: Tue, 22 Jun 1999 14:54:00 -0500 SAW THE SHOW MYSELF AND WAS VERY INTERESTING THANKS! TOM L. Bob Fryer wrote: > Hi gang, > > Well, the show title was not really consistent with the content. However, > the first part demonstrated the reasons and attitudes that drive the naval > services to jealously guard their technology. > > The show was about a British submarine, HMS Splendid, as she went through > training to become the first British warship to fire a US Tomahawk cruise > missle. Splendid was also the first British ship to fire on the United > States since the Civil War -- the target was on San Clemente Island, CA. > (;{)> > > In the second half of the program, a most interesting part of the training > was the assignment to photograph the bottom of a (drifting) destroyer while > not alerting it. They showed video tape of the bottom of the destroyer > taken through the periscope from a distance of 10 _feet_! > > For additional related information, beyond my web page, I recommend "BLIND > MAN'S BLUFF: The Untold Story of American Submarine Espionage," by Sherry > Sontag and Christopher Drew. > > Take care, > Bob F > > >-------------------------------------------------------------------------- > > > >Hi gang, > > > >This looks like a good bet for more information on how the Navy detects > >submarines -- and the signals which precede earthquakes. > > > >"Submarine Hunter" -- tonight on the Discovery Channel, 8 pm and again at > >11, PDT. > > > >For the newcomers, the Dept of Defense admitted to Senator Alan Cranston > >that they did have the technology -- 25 years ago! > > ----- earthquake WARNING research ----- > --- animals, people, scientific evidence --- > --- http://www.teleport.com/~bfryer --- > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: GPS antenna From: Greg Date: Wed, 23 Jun 1999 21:53:03 -0700 Someone was talking about a GPS antenna a while back. This one has a male MCX connector. It's in an old Ham Radio Outlet catalog. They have it online now at http://www.hamradio.com/ I can't look at because I don't have Adobe Acrobat installed right now. I just lost a motherobard and a hard drive. The model number in the catalog is "GPS-1" ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Light From seismic Waves From: Arie Verveer Date: Fri, 25 Jun 1999 13:52:46 +0800 I came across this interesting article by Dr. A. C. Johnston in a scientific magazine called Nature. This may be of interest to the PSN community. Gathering data on such sightings would be a good project to do if your in an active seismic area. Sorry about the length of the document but i think its worth it. Arie -------------------------------------------------------------------- Article Nature Vol 354 (5 December 1991) page 361. By Arch C. Johnston Light from seismic waves Sir - Sonoluminescence (SL) - the production of light by the action of sound waves in liquid - has been observed and studied in the laboratory for more than 50 years. But I believe it has been observed in nature for centuries as earthquake lights (EQLs). EQLs are largely a coseismic occurrence, second only to pre-seismic abnormal behaviour for difficulty of reliable documentation and lack of a verifiable explanatory mechanism. Many explanations for the generation of EQLs exist (see refs 1-3). Most proposed mechanisms require assumptions such the presence of special minerals, gases or organisms, or unverified physical conditions in the fault zone. All have difficulty explaining the persistent reports of EQLs at distances of up to hundreds of kilometres from the earthquake, and at sea or in association with large bodies of both fresh and salt water or wetlands. I propose that at least some EQLs are not the product of high strain accumulation or shear rupture dynamics in fault zones, but rather result from molecular reactions in water that has been strongly shaken by the compressional (P) waves produced by the earthquake. A seismic wave is simply an earthquake generated sound wave in a solid or liquid; hence if a P wave induces light emission from liquid, it is a situation entirely analogous to SL as generated in the chemist's laboratory. SL is a remarkable consequence of acoustic cavitation in liquids irradiated by sound waves(4,5). For it to occur, a cavity or bubble must be created in the liquid continuum, then rapidly compressed. The process adiabatically heats the trapped gas or vapour sufficiently to dissociate molecules. On recombination or return to the ground state, photons are emitted. Once a cavity or bubble is formed, two types of SL are possible: "stable", in which the bubble resonates and incrementally grows, usually in a standing wave field; and 'transient', in Which the bubble expands and implodes all within one cycle of a standing or travelling sound wave. A travelling P wave should be an efficient stimulus of transient cavitation, although long trains or strong-motion P waves may induce Stable cavitation SL as well. The observed SL spectrum in water has a peak at 310 nm (in the ultraviolet), arising from the return to the ground state of the excited hydroxyl radical (OH); there is also a poorly understood continuum throughout the visible waveband. A pure water SL spectrum will appear blue to bluish-white, but the but the presence of dissolved salts or other impurities can appreciably alter the basic aqueous spectrum(6), so that yellow or red may predominate. SL has been generated in the laboratory with ultrasonic pressure amplitudes of 1-2 bar (0. 1-0.2 MPa)', corresponding roughly to an energy density in the ambient fluid of 10-20 erg cm-3. Whether SL is a viable mechanism for EQLs hinges on the question of whether it is reasonable that P waves of sub audible frequency can supply this energy density in water. The density of the kinetic energy, e (per unit volume), induced in the transmission medium by one cycle of an advancing seismic wavefront is a standard result in seismology(7) and is given by 2 2 e = 2(Pi) * p *(Ao/to) where "p" is the density of the medium and "Ao" and "to" are the displacement amplitude and period respectively of the seismic wave. Conservatively estimated values for "Ao" of 1-10 cm and "to" of 0.1-1.0 s may be obtained from the strong ground motion recordings of earthquakes. This yields P-wave energy densities in water of roughly 500-2,000 erg cm-3 at 10-1 Hz and pressure differentials of 1.3-2.7 bar. Thus, seismic P waves are capable of supplying pressure changes and energy densities that exceed the laboratory values that induce SL. Within the water volume irradiated by P waves, EQLs would arise as the integrated light flux from many SL cavitation bursts, all loosely synchronised by the P-wave dilational half-cycles. In the laboratory, SL produces an illuminance of ~10-(8) lumen CM-(2) (ref.8), which is visible to the dark- adapted eye. Thus, to reproduce an illuminance equivalent to moonlight of 10-(4) lumen cm-(2), as reported for EQLs in Japan(9), ~10(4) ultrasonic SL bursts are required in the laboratory. For the much larger P-wave cavitation events (with bubble micrometre range), the same illuminance could arise from a single event. To illuminate a landscape to moonlight brightness from at least several kilometres distance, 10(2) -10(4) individual SL P-wave bursts would be sufficient. A P- wave with a dilational half-cycle wavelength of ~ 1 km is certainly capable of spawning such an SL field. Reports of EQLs for large nocturnal earthquakes are not ubiquitous, but neither are they extremely rare. Selected characteristics relevant to the SL hypothesis that appear in the EQL literature are: (1) distinct blue to bluish-white EQLs reported from coastal Japan(10) and Hawaii(2); (2) extensive EQLs from an onshore alluvial setting(11); (3) numerous accounts of EQLs sighted offshore from California(1), Mexico(11) and other coastal zones; and (4) well-defined, blue and yellow spherical lights in tsunami wavecrests . (Luminescent organisms may be another source of luminescence in tsunami wavecrests(13), but I do not believe that they would create well defined spheres of light.) Natural SL is perhaps not the only mechanism that produces EQLS, but it is able to explain a wide range of the existing reports. The hypothesis predicts that (1) EQLs should not be confined to the immediate fault rupture zone; (2) bodies of water must be present, although it is possible that saturated soil can sustain SL; (3) EOLs are essentially a coseismic phenomenon, which in the absence of strong foreshocks or aftershocks should not be observed before or more than several minutes after the earthquake; and (4) the EQL spectrum should contain a prominent hydroxyl peak at 310 nm (and for sea water(6) a sodium peak at 589 rim). Hence the SL-EQL hypothesis can be tested by means of spectrographic analysis although obtaining an EQL spectrum will not be a trivial undertaking. ARCH C. JOHNSTON Center for Earthquake Research, Memphis State University, Memphis, Tennessee 38152, USA 1. Derr, J. Bull. seis. Soc. Am. 63, 2177-2187 (1973). 2. Lockner, D. A., Johnston, M. J. S. & Byerlee, J. D. Nature 302, 28-33 (1983). 3. Brady, B. T. & Rowell. G. A. Nature 321, 488-492 1986). 4. Barber, B. P. & Putterman, S. J. Nature 352, 318-320 (1991). 5. Suslick, K. s. science 247, 1439-1445 (1990). 6. Suslick, K. S. & Flint, E. B. J. Phys. Chem. 95, 1484 (1990). 7. Kasahara. K. Earthquake Mechanics (Cambridge University Press, (1981). 8. Walton. A. J. & Reynolds, G. T. Adv. Phys. 33, 595-660 (1984). 9. Musya. K. Bull. Earthquake Res. inst. Tokyo univ. 9, 214-215 1931). 10. Terada, T. Bull. Earthquake Res. Inst. Tokyo Univ. 9, 225-255 (1931). 11. Fuller, M. 1. U.S. Geol. Sutv. Bull. 494, 120 (1912). 12. Musya, K. Bull. Earthquake Res. Inst. Tokyo Univ. 10, 666-673 (1932). 13. Terada, T. Bull. Earthquake Res. Inst. Tokyo Univ. 1, 25-35 (1934). -------------------------------------------------------------------- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Where is Pete Rowe? From: Edward Cranswick Date: Fri, 25 Jun 1999 13:28:22 -0600 Does anyone know Pete Rowe's email address or his whereabouts? I haven't heard from him since the PSN at USGS Menlo Park last December. -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: historic seismogram From: robert barns <75612.2635@..............> Date: Sun, 27 Jun 1999 10:18:28 -0400 Hi gang, what's shakin'? Ebay (www.ebay.com) currently has an item which may be of some interest. It is a seismogram of the 1989 Loma Preita 'quake made by the "Old Faithful" station. It is item #123104193 and the current price is $= 5. The auction ends 7/3. Item #119485409 claims to have something to do with seismology but I find it a mystery. Anyone who makes sense of this should post a note. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: STM-8 CONSTRUCTION From: RADIOTEL@....... Date: Sun, 27 Jun 1999 11:58:33 EDT Sean-Thomas, et. al What effect do you think using a larger (next size up) floating bar at the leaf spring end, filing the top flat and securing the spring with a flat strip of brass across the spring end secured with the two 4-40 screws. This would eliminate the need for the square tubing. I plan to use 3/16 bar for the fixed rod. Is it necessary to make a slit in the bar for the flecures or could they just be soldered around the rods? At one point you indicated you were going to experiment with using stainless steel fishing leader for the flexures. Did this improved the period? As always, your help is greatly appreciated. Jim Allen Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: [Fwd: [Fwd: updated PSN station list]] From: Steve Hammond Date: Sun, 27 Jun 1999 16:58:18 -0700 Station codes -- This is the last list. Here is the updated list I thought I cc'ed you on it. Bob Ogborn was added in a latter note. Regards, Steve This is the station list with your map ID number is a new listing. All names without (xx) are new stations added to the list. This has already been submitted to Steve Malone for the Council of the National Seismic System Assessment and IASPEI Handbook. Regards, Steve Hammond Field 1 Station Operator ID Field 2 Latitude Longitude Field 3 XXX see legend (1st,2nd,3rd charachter 1st charachter J = Short period <10 seconds O = Long-period >10 seconds E = Accelerometer 2nd charachter S = Short period corner <10 seconds B = Broad Band 10 to 89 seconds H = smoke / chart recorder >80 seconds 3rd charachter Number of orientations (ie 1-single channel) 1 NAME: Al Allworth W7PXX (51) AA1 42.51 -124.33 JS1 2 Name: Almaden Country Middle School ACS 37.12 -121.5 OB1 3 NAME: Albert Judge (Alby) (37) AJ1 -32 115 OB1 4 NAME: Arie Verveer (59) AV1 -32.0083 116.1346 OB2 5 NAME: Bob Hammond (13) BH1 64.921 -147.937 JH1 6 NAME: Bob Hammond (13) BH2 64.921 -147.937 OH1 7 NAME: Barry Lotz (15) BL1 39.23 -121.07 OB1 8 NAME: Bill Scolnik (28) BS1 41.05 -74.25 JS1 9 NAME: Bill Scolnik (28) BS2 33.5 -74.25 OB2 10 NAME: Bob Teller (9) BT1 46.19 -111.3 OB3 11 NAME: Charlie Thompson (10) BUE 30.112 -97.891 OB2 12 NAME: Brian Zimmerman (16) BZ1 41.875 -80.125 JS1 13 NAME: Brian Zimmerman (16) BZ2 41.875 -80.125 OB2 14 NAME: Claudio Conti (58) CC1 37.035 15.135 OB1 15 NAME: Claudio Conti (58) CC2 37.035 15.135 SJ3 16 Name: Clark Wockner (43) CW1 40.78 -87.75 OB1 17 NAME: Darrell Collins (27) DC1 33.5 -111.9 JS1 18 NAME: Darrell Collins (27) DC2 33.5 -111.9 OB2 19 NAME: Malcolm Sinclair (32) DHQ -45.6 170.4 JH1 20 NAME: Dennis Leatart (8) DL1 34.1 -118.88 JS1 21 NAME: Douglas McConnell (49) DM1 -30.317 149.988 OH1 22 NAME: Dave Nelson ZL4TBN (4) DN1 -45.8 170.3 JS1 23 NAME: Dave Nelson ZL4TBN (4) DN2 -45.8 170.3 JS1 24 NAME: Dave Nelson ZL4TBN (4) DN3 -45.8 170.3 JS1 25 NAME: Dave Nelson ZL4TBN (4) DN4 -45.8 170.3 OB1 26 Name: Donald Sieber (retired) (47) DS1 43.61 -116.21 JS1 27 NAME: Fred Bruenjes (2) FB1 32.822 -117.084 OB1 28 NAME: Fred Bruenjes (2) FB2 32.822 -117.084 OB1 29 NAME: Frank Cooper W5VID (20) FC1 29.52 -95.17 OB1 30 NAME: Bob Lewis WB5FDF (39) FD1 33.1 -96.43 OB1 31 NAME: Bob Lewis WB5FDF (39) FD2 33.1 -96.43 JS1 32 NAME: Francesco Nucera (53) FN1 -43.29 13.29 OS1 33 NAME: Francesco Nucera (53) FN2 -43.29 13.29 JS2 34 NAME: Francesco Nucera (53) FN2 39.96 -82.98 OB1 35 NAME: Steve Hammond (18) FSX 37.245 -121.815 OB2 36 NAME: Steve Hammond (18) FSZ 37.245 -121.815 JS3 37 NAME: David Wolny (34) GJC 39.079 -108.554 OB1 38 NAME: Gregory A. Lyzenga (7) GL1 34.2 -118.13 OB1 39 NAME: Giovanni Rotta (45) GR1 46.22 13.18 JB1 40 Name: Grayling School, Alaska GRY 62.8 -160.1 OH1 41 NAME: South Valley Jr. High GS1 37 -121.6 OB1 42 Name: HSC; Fairbanks, Alaska HSC 62.8 -160.1 OH1 43 NAME: Jeff Batten (25) JB1 34.13 -118.12 JS2 44 NAME: Jeff Batten (25) JB2 34.13 -118.12 OB1 45 NAME: Jeff Batten (25) JB3 34.13 -118.12 JH1 46 NAME: Jean-Jacques Hunsinger (41) JCH 47.5 7 OB1 47 NAME: Jerry Darby JD1 36.65 -119.3 OB1 48 NAME: Jim Lovell (22) JL1 -43.52 172.61 OS1 49 NAME: Jack Sandgathe (23) JS1 49.35 -119.62 OB1 50 NAME: Karl Cunningham (40) KC1 32.7705 -116.97775 JS1 51 NAME: Karl Cunningham (40) KC2 32.7705 -116.97775 EH1 52 NAME: Karl Cunningham (40) KC3 32.7705 -116.97775 OB1 53 NAME: Kim Froom KF1 34.9 -121.45 OB1 54 NAME: Ken Navarre (21) KN1 37.39 -121.99 OB1 55 NAME: Kees Verbeek (12) KV1 51.26 5.3 JH1 56 NAME: Larry Cochrane (1) LC1 37.496 -122.241 OB1 57 NAME: Larry Cochrane (1) LC2 37.496 -122.241 JS3 58 NAME: Larry Cochrane (1) LC3 37.496 -122.241 OB1 59 NAME: Lucas Haag (11) LH1 40.13 -100.29 JS1 60 NAME: Tom Frey (26) LK1 47.17 -122.49 OB1 61 NAME: Liberio Rossi (56) LR1 43.54 10.34 JS3 62 Name: Martin S. Brewer (44) MB1 32.278 -64.793 OB2 63 Name: McGrath School, Alaska MCG 62.9 -155.6 OH1 64 NAME: Mark Halliday (5) MH1 37.085 -122.106 JS1 65 NAME: Mark Halliday (5) MH2 37.085 -122.106 OB1 66 NAME: Meredith Lamb (52) ML1 39.703 -105.006 OB1 67 NAME: Meredith Lamb (52) ML2 39.703 -105.006 OB1 68 NAME: Meredith Lamb (52) ML3 39.703 -105.006 OB1 69 NAME: Malcolm Sinclair (32) MS1 -43.55 172.68 JH1 70 Name: Pearl Creek School, Alaska PCK 64.9 -147.8 OH1 71 NAME: Paolo Frediani (57) PF1 44.13 10.06 SJ2 72 NAME: Paolo Frediani (57) PF2 44.13 10.06 OB1 73 NAME: Pete Rowe PR1 37.38 -121.79 JS1 74 NAME: Robert (Bob) L. Barns (3) RB1 40.6802 -74.4142 OB1 75 NAME: Roger Griggs (6) RG1 37.98 -121.72 OB1 76 NAME: Robert L. Laney (50) RL1 38.902 -77.38 OB2 77 NAME: Charlie Rond (35) RM1 35.041 -89.84 OB1 78 NAME: Roberto E. Pozzo (38) RP1 44.46 8.21 OB1 79 NAME: Roberto E. Pozzo (38) RP2 44.46 8.21 JS1 80 NAME: Roger Sorensen (19) RS2 34.2711 -118.59386 JS3 81 NAME: Dick Webb (30) RW1 35.54 -78.39 OB1 82 Name: Ron Westfall (42) RW1 49.325 -122.996 OB2 83 NAME: Steve Clark (24) SC1 44.99 -122.96 JS1 84 NAME: Phil Giannini (17) SFX 37.72 -122.416 OB2 85 NAME: Phil Giannini (17) SFZ 37.72 -122.416 JS1 86 NAME: Sam Gazdik SG1 41.8 -123.2 OB2 87 NAME: Southland Boys High School (60) SHS -46.5 168.2 SJ1 88 NAME: Stephen Mortensen (55) SM1 38.828 -120.978 OB1 89 NAME: Phil Giannini (17) SMX 37.75 -122.2 JN3 90 NAME: Phil Giannini (17) SMZ 37.75 -122.2 JN3 91 Name: SRA, Fairbanks, Alaska SRA 62.8 -160.1 OH1 92 NAME: Peter Styles, Sam Toon (36) ST1 53.4 -2.96 JS1 93 NAME: Ted Blank TB1 37.21 -121.85 OB1 94 NAME: Tony Potenzo (46) TP1 19.723 -155.991 OB1 95 NAME: Tony Potenzo (46) TP2 19.723 -155.991 JS1 96 NAME: George Bush (14) TSR 38.74 -123.5 EH3 97 NAME: Phil Giannini (17) TVN 37.75 -122.2 OB1 98 NAME: Phil Giannini (17) TVZ 37.75 -122.2 JS1 Subject: [Fwd: LAte late PSN additions] From: Steve Hammond Date: Sun, 27 Jun 1999 16:58:58 -0700 station list update 1 Steve An error was just brought to my attention. I missed three of the main PSN stations in the survey... can you add them? Thanks-- Steve Hammond RPC 37.24 -121.845 OB1 PSN BK1 37.24 -121.839 OB1 PSN GC1 37.5 -126.1 OB2 PSN Subject: Re: PSN Station Codes From: Steve Hammond Date: Sun, 27 Jun 1999 17:04:40 -0700 Greg, I like the idea that they be on the WEB. I just posted the lists that I made last year for the Library of Congress listing. Feel free to manage the updates. Regards, Steve Hammond PSN San Jose Greg wrote: > > If nobody else wants too, I can be the coordinator. Buelller? Bueller? > Bueller? > > Okey dokey? Should we have a vote or something? Motion to burn Greg at > the stake? > > Should the station ID numbers be somewhat private or on a web page? I > have more than enough server space for a web page. > > Should it be first come, first served? Or maybe a battle to the death? > > ,Greg > > "Rex Klopfenstein, Jr" wrote: > > > > Am I missing something! Is there a 'clearinghouse' for assignment of > > station codes? Is there a place (USGS) to find the allocated PSXX0 > > codes. I am thinking of picking PSBG0 as my station code. > > > > Any feedback would be appreciated > > > > Rex Klopfenstein, Jr > > Bowling Green, OH > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: PSN Station Codes From: Steve Hammond Date: Sun, 27 Jun 1999 17:06:27 -0700 No-- there is no offical place. We just picked one and then checked to see if it was in use. I just posted the lists I have. Regards, Steve Hammond PSN San Jose Rex Klopfenstein, Jr wrote: > > Am I missing something! Is there a 'clearinghouse' for assignment of > station codes? Is there a place (USGS) to find the allocated PSXX0 > codes. I am thinking of picking PSBG0 as my station code. > > Any feedback would be appreciated > > Rex Klopfenstein, Jr > Bowling Green, OH > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: [Fwd: [Fwd: updated PSN station list]] From: Wayne Abraham J73WA Date: Sun, 27 Jun 1999 14:30:36 -0400 Curious Stuff. I wonder what is going to happen to DM1. I have been using DM1, DM2 and DM3 for the past 6 months and have posted dozens of event files with these extensions for Dominica. Recently I registerred DMA with the NEIC. Wayne Steve Hammond wrote: > Station codes -- This is the last list. 21 NAME: Douglas McConnell (49) DM1 -30.317 149.988 OH1 -- Wayne Abraham 1430 Rodney Street Portsmouth, Dominica abrahamw@........ http://www.freeyellow.com/members6/dominicapsn/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: quake picture From: JIm Hannon Date: Sun, 27 Jun 1999 19:31:20 -0500 Here ftp://ftp.nofs.navy.mil/pub/outgoing/aah/temp/quake29.jpg is an interesting picture that was taken through a large telescope in Flagstaff AZ during a small earthquake on April 29 1993. You can see the bottom star has a lot of little lines showing the motion of the scope during the quake. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake picture From: Karl Cunningham Date: Mon, 28 Jun 1999 00:12:16 -0700 Jim -- Very interesting picture. Where did you ever come across that??? -- Karl At 07:31 PM 6/27/99 -0500, you wrote: >Here ftp://ftp.nofs.navy.mil/pub/outgoing/aah/temp/quake29.jpg is an >interesting picture that was taken through a large telescope in Flagstaff AZ >during a small earthquake on April 29 1993. You can see the bottom star has a >lot of little lines showing the motion of the scope during the quake. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: WinQuake From: John Lahr Date: Mon, 28 Jun 1999 15:26:04 -0600 (MDT) Hi Larry, Is there a way in WinQuake to find out the time correction that has been applied to the data? Sometimes I make repeated "fixes" and then can't figure out what the total corrections is. Thanks, JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: winquake data directory From: "Francesco" Date: Tue, 29 Jun 1999 00:48:47 +0200 Hi Larry, at 01/06/99 Wq have not created the 9906 directory. This is the message: = "error creating new directory". The same trouble in May. Which is the way to resolve the problem? (I have more time reinstalled = the program or upgrated it). Francesco
Hi Larry,
at 01/06/99 Wq have not created the 9906 directory. This is the = message:=20 "error creating new directory". The same trouble in May.
Which is the way to resolve the problem? (I have more time = reinstalled the=20 program or upgrated it).
 
Francesco
Subject: S-G Seismometer Photos From: "Rex Klopfenstein, Jr." Date: Mon, 28 Jun 1999 20:01:57 -0400 Several weeks ago someone wanted to see my seismometers. I have just added some photos to my home page (http://www.wcnet.org/~rklopfen). As soon as I empty my camera, I will add photos of my insulating boxes and my 'vault'. To get an idea of scale, the base is a piece of cast alum tool plate 3/4" x 6" x 12" and the overall height is 18-1/2". I do have a set of AutoCAD files for parts and assemblies, but they are not checked very close and may be missing some details!!! I tried to change drawings to reflect 'run changes', but I am sure I missed a few. -- Rex Klopfenstein, Jr. Bowling Green, OH rklopfen@......... www.wcnet.org/~rklopfen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: WinQuake From: Larry Cochrane Date: Mon, 28 Jun 1999 17:09:36 -0700 Hi John, No, there is no field in the PSN format to save this info. SDR and WinQuake can indicate if the time was locked when the event file was created. It does this by using one spare byte in the header part of the record. -Larry At 03:26 PM 6/28/99 -0600, you wrote: >Hi Larry, > >Is there a way in WinQuake to find out the time correction >that has been applied to the data? Sometimes I make >repeated "fixes" and then can't figure out what the total >corrections is. > >Thanks, >JCLahr > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: PSN Station Codes From: Edward Cranswick Date: Mon, 28 Jun 1999 18:10:34 -0600 Steve- I appreciate you redistributing the station info you compiled last year. Though I have made various remarks, heavy-handed and otherwise, on the subject of submitting PSN data to the NEIC, all I am doing is acting as some kind of de facto liason between the PSN and the NEIC. Ultimately, the PSN will work out some system with the station codes that is compatible with the NEIC system. I don't know exactly how that will go; I have just made some suggestions. I do agree with you that the PSN station code list should be accessible via the Web. I also think that the input of the PSN members is necessary so we can find out what we think. -Edward Steve Hammond wrote: > No-- there is no offical place. We just picked one and then checked to > see if it was in use. I just posted the lists I have. > Regards, Steve Hammond PSN San Jose > > Rex Klopfenstein, Jr wrote: > > > > Am I missing something! Is there a 'clearinghouse' for assignment of > > station codes? Is there a place (USGS) to find the allocated PSXX0 > > codes. I am thinking of picking PSBG0 as my station code. > > > > Any feedback would be appreciated > > > > Rex Klopfenstein, Jr > > Bowling Green, OH > > > > _____________________________________________________________________ > > > > Public Seismic Network Mailing List (PSN-L) > > > > To leave this list email listserver@.............. with the body of the > > message: leave PSN-L > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake picture From: Edward Cranswick Date: Mon, 28 Jun 1999 18:13:51 -0600 Jim- Fascinating! but why only the bottom star? and why do some stars seem to blurred from rotation and others are not? -Edward JIm Hannon wrote: > Here ftp://ftp.nofs.navy.mil/pub/outgoing/aah/temp/quake29.jpg is an > interesting picture that was taken through a large telescope in Flagstaff AZ > during a small earthquake on April 29 1993. You can see the bottom star has a > lot of little lines showing the motion of the scope during the quake. > > -- > Jim Hannon > http://soli.inav.net/~jmhannon/ > 42,11.90N 91,39.26W > WB0TXL > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: winquake data directory From: Larry Cochrane Date: Mon, 28 Jun 1999 17:37:21 -0700 Hi Francesco, Don't know. Can you create the directories using Windows Explorer or in a DOS box using the MKDIR command? -Larry At 12:48 AM 6/29/99 +0200, you wrote: >>>> Hi Larry, at 01/06/99 Wq have not created the 9906 directory. This is the message: "error creating new directory". The same trouble in May. Which is the way to resolve the problem? (I have more time reinstalled the program or upgrated it). Francesco <<<<<<<< _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: ADXL202 From: barry lotz Date: Mon, 28 Jun 1999 18:06:40 -0700 Well I got two Analog devices ADXL202's. It has a couple of interesting attributes. It's two axis for one. Secondly it has a "duty cycle" option where one can read the acceleration(s) without an AD converter. You simply measure the duty cycle length of a predefined cycle. The width of the step is related to the acceleration. It has the usual drawback in that it is a 2g accelerometer. ie milli g resolution. It is also low power (<0.6 ma). I think I will hook it up to an extra SDR channel and see what happens. BTW I'm not sure whether to read acceleration and integerate it in Winquake or include a hardware integrator before recording. The hardware integrator has a more limited bandwidth but recording accelerations would require a higher sampling rate. Any thoughts? Regards Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: quake picture From: JIm Hannon Date: Mon, 28 Jun 1999 20:22:17 -0500 Edward Cranswick wrote: > Jim- > Fascinating! but why only the bottom star? and why do some stars seem to > blurred from rotation and others are not? > -Edward > -- > Edward Cranswick Tel: 303-273-8609 > US Geological Survey, MS 966 Fax: 303-273-8600 > PO Box 25046, Federal Center cranswick@........ > Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". Edward, If you look closely at the picture you will see some movement of some of the other brighter stars. The bottom star is the brightest and has enough light to record on the CCD camera while moving. These picture generally take several minutes of exposure so only the brighter stars would show the streaks during the quake. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: ADXL202 From: Edward Cranswick Date: Mon, 28 Jun 1999 21:17:41 -0600 Barry- You could try recording both from the same sensor as an experiment and compare the results. -Edward barry lotz wrote: > Well I got two Analog devices ADXL202's. It has a couple of interesting > attributes. It's two axis for one. Secondly it has a "duty cycle" option > where one can read the acceleration(s) without an AD converter. You > simply measure the duty cycle length of a predefined cycle. The width of > the step is related to the acceleration. It has the usual drawback in > that it is a 2g accelerometer. ie milli g resolution. It is also low > power (<0.6 ma). I think I will hook it up to an extra SDR channel and > see what happens. BTW I'm not sure whether to read acceleration and > integerate it in Winquake or include a hardware integrator before > recording. The hardware integrator has a more limited bandwidth but > recording accelerations would require a higher sampling rate. Any > thoughts? > Regards > Barry > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Old PC Convertible - can it be upgraded? From: Ted Blank Date: Mon, 28 Jun 1999 22:20:39 -0700 (PDT) I have a friend who will give me an old PC Convertible (or "luggable" as we used to call it). I remember someone at the last PSN meeting had one which was customized for portable quake recording. The one I may get has only a 720K floppy drive and no hard drive. Is there any way to upgrade the machine to have 1.44Mb drives and hopefully a hard drive? I can't remember if the one at the PSN meeting had a hard drive, but I think it did. If anyone remembers who had it, please let me know... Thanks. Ted Blank San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Old PC Convertible - can it be upgraded? From: Greg Date: Mon, 28 Jun 1999 22:46:06 -0700 Ted Blank wrote: > The one I may get has only a 720K floppy drive and no hard drive. Is > there any way to upgrade the machine to have 1.44Mb drives and hopefully > a hard drive? I can't remember if the one at the PSN meeting had a hard > drive, but I think it did. If anyone remembers who had it, please let me > know... Thanks. If it has an expansion slot (probably ISA) you might be able to plug in a multi-IO board and get it all working. Some of them have their own BIOS to set up hard drives. I doubt there's much room inside for a hard drive though. If you wanted to use Larry's ADC board it might be a bit too big to fit and you would need another ISA slot. I think your best bet is a serial port ADC thingy, and for that why not get a regular laptop? One last thought is a BIOS upgrade for the motherboard. I can't remember the name of the company, but they claim to have a lot of BIOS upgrades for older computers. This might be them : http://www.mrbios.com/ ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: PSN-L list archives From: Larry Cochrane Date: Mon, 28 Jun 1999 23:14:37 -0700 All, I added a new way of archiving and display PSN-L messages too my system last week. The current way of archiving messages, all in one text file for each quarter, still works the same. What I added was a way of saving individual messages as they come in as a web page and creating or updating an index web page with links to the messages. You will find a link to the new index page here http://www.seismicnet.com/maillist.html under the PSN-L archive section. The index page will get very large soon, so I need to figure out a way organizing things better. Maybe a sub-index page for each month and one master index page pointing to the monthly index pages. Please let me know if you see an problems with this new archive system. Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Old PC Convertible - can it be upgraded? From: "Charlie Rond" Date: Tue, 29 Jun 1999 02:23:58 -0500 Ted, >I have a friend who will give me an old PC Convertible (or "luggable" as >we used to call it). I remember someone at the last PSN meeting had one >which was customized for portable quake recording. > >The one I may get has only a 720K floppy drive and no hard drive. Is >there any way to upgrade the machine to have 1.44Mb drives and hopefully >a hard drive? I can't remember if the one at the PSN meeting had a hard >drive, but I think it did. If anyone remembers who had it, please let me >know... Thanks. I thought I had an ideal answer for you! I have an IBM P70 portable computer which was a "luggable" with a plasma screen, full-size keyboard and hard drive (actually the IBM Model 70 computer in a portable configuration). The ONLY drawback is its Micro-Channel Architecture, so you would have to have an A/D card for an MCA bus. Like the PC Convertible, it did not have a battery pack, but required A/C power. So much for my "perfect answer" to a portable system for seismology But I'll bet Steve Hammond could tell you what you will need for the PC Convertible! _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Using Lasers/Ham Radio From: Denny Goodwin Date: Tue, 29 Jun 1999 06:39:48 -0500 All - Just joined the e-mail net and got my first messages. Becoming interested in seismic measurements - again. Several years ago a friend and I both made swinging gates and we experimented with various detection methods but we never followed up on project. He recently purchased a surplus 10 Hz geophone and has tinkered with it some. Anyone using lasers for detection - if so, how? I am also a ham radio operator. Are there any ham nets devoted to seismic work? Would be interested to hear. Thanks... Denny Goodwin, KF4BL dennygwin@........ ___________________________________________________________________ Get the Internet just the way you want it. Free software, free e-mail, and free Internet access for a month! Try Juno Web: http://dl.www.juno.com/dynoget/tagj. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Using Lasers/Ham Radio From: Raul Alvarez Date: Tue, 29 Jun 1999 06:32:20 -0600 Denny, I did some experimenting a while back on this, but then put it on the back burner. The idea was to reflect a beam from a small mirror on the sense arm to a linear ccd detector, sensing displacement by which cell or cells were "on". Raul Denny Goodwin wrote: > All - > Just joined the e-mail net and got my first messages. Becoming > interested in seismic measurements - again. Several years ago a friend > and I both made swinging gates and we experimented with various detection > methods but we never followed up on project. He recently purchased a > surplus 10 Hz geophone and has tinkered with it some. > > Anyone using lasers for detection - if so, how? > > I am also a ham radio operator. Are there any ham nets devoted to > seismic work? Would be interested to hear. Thanks... > > Denny Goodwin, KF4BL > dennygwin@........ > > ___________________________________________________________________ > Get the Internet just the way you want it. > Free software, free e-mail, and free Internet access for a month! > Try Juno Web: http://dl.www.juno.com/dynoget/tagj. > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: PSN-L list archives From: The Lahrs Date: Tue, 29 Jun 1999 08:16:54 -0600 Hi Larry, The ability to search the text of all of the messages would be the most valuable feature you could add. I don't know if any of the search programs are free, so the software expense could be a problem. If all of the messages were in individual files, then one could create a "search engine" of sorts based on the grep command. John * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * AOL version of homepage: * * http://lahr.org/john-jan/homepage.html * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Old PC Convert From: Phil Giannini Date: Tue, 29 Jun 1999 08:02:37 -0700 Hi Ted and Gang, I was the one with the converted luggable. But I cheated and completely gutted the machine and installed a 386 DX40 mother board, 9 inch B/W VGA monitor, 500 meg hard drive, 1.44 floppy, and still had room to build in one of Larry's demod boards. I also modified the power supply to work on AC or from 12VDC so it could be operated in remote locations from a 12v car battery when no AC power is available. An AT type keyboard was modified to fit in the luggable's fold down door/bottom, as the luggable originally used an XT type keyboard that wouldn't work on the 386 mother board. The system is using the PC Labs 12 bit A/D board modified for time lock running Larry's SDR software and Winquake. There is also a 33.6 modem on board so I can upload any captured events if there is a phone line available at the remote location. On another note, I noticed that the station names on the list for me are incorrect. I don't know if that is just a typo or if they are actually listed that way. If so can they be corrected? They should be SFN and SFZ, and I would like to reserve SFE for the partly finished E/W sensor I am building. Also the TVZ listing can be removed from the list as that system has been retired. Thanks and sorry for any inconvenience that may have created. Regards, Phil SFN & SFZ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Placer 400 problems From: The Lahrs Date: Tue, 29 Jun 1999 09:19:12 -0600 I sent this message to Trimble, but no answer yet. Is anyone using the Placer 400 and having similar problems? Thanks, John Hello, I'm running a Placer GPS400 gps unit with the latest version of GPSSK.EXE from your web site (GPSSK V2.04). I'm using a small 10V 500ma power supply for the main power and a 9V battery for backup power. I've measured the voltage on the power connector that attaches to the Placer 400 and the voltages are OK. I used the DOS mode command: mode com1:4800,n,8,1 prior to running GPSSK, and this reduced the number of garbled lines that the PC receives. The unit does get the correct coordinates most of the time but also reports: Battery Back-Up Failed Battery Powered Timer/Clock Fault Is there an internal Lithium battery? If necessary, how can I get this unit repaired? Placer 400 P/N 22442-01 S/N 0080224858 B G104 Z T 284C GPS Computer: laptop running a DOS window under Win95 (Same results when booted up into DOS) VR Product SVEESIX Version 4.06 Release Date 05/18/94 ST Machine ID 20 -> 6 Channel TANS Error Code 1 Battery Back-Up Failed Error Code 2 Batt Powered Timer/Clock Fault Thanks, John C. Lahr U.S. Geological Survey Golden, CO (Also, lahr@......... * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * AOL version of homepage: * * http://lahr.org/john-jan/homepage.html * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: ADXL202 From: barry lotz Date: Tue, 29 Jun 1999 19:32:52 -0700 Ed Good Idea. I'll try. Barry Edward Cranswick wrote: > Barry- > You could try recording both from the same sensor as an experiment and > compare the results. > -Edward > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: New station on the map From: Larry Cochrane Date: Tue, 29 Jun 1999 21:26:27 -0700 All, Since Dave Nelson isn't around I added a new station to the PSN station map. Please welcome Dennis Pope, he is station number 69 on the station list. Heres the information he sent in: Name: Dennis W. Pope Email: dwpope@.............. Home Page: no homepage City: Reynoldsburg State: Ohio County: USA Lat: / Long: 39.9733N 82.8028W Ground Type: Glacial morain Equipment: Guralp CMG-PEPPV vertical broadband digital seismometer, GPS timing, PC (133mhz) capture using SCREAM software. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: PSN-L list archives From: Larry Cochrane Date: Tue, 29 Jun 1999 21:44:32 -0700 Hi John, I have a program that can create an index of web pages that can be searched for keywords. I use it to produce the search link on my main web page. I will add the new mail list web page directory to the list of directories the program currently searches in. Right now I have to manually run a program that creates the database that can be used to search for keywords. I need to automate this and also create a separate database for the email message. This way the user can search for info only in the PSN-L email message web pages. -Larry Cochrane Redwood City, PSN At 08:16 AM 6/29/99 -0600, you wrote: >Hi Larry, > >The ability to search the text of all of the messages would be the most >valuable feature you could add. I don't know if any of the search >programs are free, so the software expense could be a problem. > >If all of the messages were in individual files, then one could >create a "search engine" of sorts based on the grep command. > >John _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: my maps From: dave nelson Date: Tue, 29 Jun 1999 23:58:57 PDT Larry, thanks for that. i dont have ftp on the puter im using at present. im still alive and sending greetings from portland, oregon. i will be back in new zealand from the 12 july and will be back online asap after that once i get isp access etc set up Dave _______________________________________________________________ Get Free Email and Do More On The Web. Visit http://www.msn.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L)