© Brooke Clarke 2007 -2020

Hilger Watts

Quake Alarm

Hilger & Watts  Seismometer
Geophone Quake Alarm EarthQuake Alert
Vibration Sensors
Hilger & Watts
    SH-1 Horizontal Seismometer
        Cal Tech (SH-1)
    FC-1 Field Calibrator
    SMA-1 Seismograph
Quake Alarm
EarthQuake Alert
Atomic Bomb Test Ban
Earthquake Early Warning
Quake-Catcher Network


Seismometers & geophones are some of the sensor types that I find interesting.  The applications are varied. 
British Geological Survey: History of seismometer design -
YouTube: Han Dynasty Seismograph in 132AD -
The Early History of Seismometry (to 1900) -


Classically seismometers have been used to record the ground shaking as the result of earthquakes.  By measuring the time from the "P" wave to the slower waves the radial distance between the sensor and epicenter can be calculated.  The magnitude and duration of the slow waves gives an indication of the energy.  This is the application that first got me interested.

Oil Exploration

Geophones are used to look for reflections caused by changes in density of sub surface layers after a surface explosion or a tamper initially shakes the ground.  These are typically used in large arrays.

Intrusion Detection

Outdoor intrusion detectors use geophones as well as other methods to detect ground vibrations caused by moving men and machines.  Knowing about the use of seismometers for recording earthquakes and  then seeing this application reinforced my interest.

Machine Balancing & monitoring

Some industrial motors are connected to a system that can be balanced so sensing the out of balance helps make the initial adjustments.
In an industrial environment when a machine is breaking down or is about to, it starts to shake and detecting the vibration allows shutting the motor off before there's a catastrophic problem.

Detecting Nuclear Blasts

As part of the Non Nuclear Proliferation treaty a need arose to detect nuclear blasts and differentiate them from other types of blasts.  Seismometers are able to do that by the wave form shape.
Note that the technology used for seismometers is very similar to that used for pendulums and gravity meters.

Monitoring Blasting associated with Mining

The book Blasting Guidance Manual (Google Books) lists the following companies that make seismic recorders to monitor blasts for compliance with federal rules:
Dallas Instruments, Digital Vibration Teleblast, Berger, Slope Indicator, Sprengnether, Vibra-Tech (VME).  I saw a Berger SSU 1000D on eBay listed as "Geosonics Berger & Associates Portable Seismograph Seismic Unit SSU 1000D"  The sensor stored in the lid looks like a microphone rather than a seismometer and it turns out that it's used as a trigger for the chart recorder.  The black device may be the vibration transducer.

Vibration Sensors

There are a number of technologies used for vibration sensing.  One of these is very similar if not identical to the geophone.  The difference may be in the frequency range that's being monitored.  Vibration sensors typically are concerned with audio frequencies and into the ultrasonic whereas geophones and seismometers are looking at infrasound frequencies.

Hilger & Watts

Label SG450, 157222, Made in England.
The Teledyne Geotech S13 Seismometer looks very similar and they show up on eBay now and then.

Variable Oscillation Period Seismometer (see patent below) that can be used vertically or horizontally.  Permanent magnet and coil of wire.
                    Watts seismometer Opened Hilger Watts
                    Seismometer Close Up Open
                    Watts Bottom wiring
Hilger Watts
Hilger Watts Seismometer Open
Hilger Watts Seismometer Close Up
Bottom showing 2 of 3 possible windings


Diameter 6.625", height to top of handle under 15" (varies with leveling feet) 27.5 pounds.
patent 3199072 page 1


Voltage Generator6 is a floating permenant magnet with a fixed coil (20) in the gap.  Three bottom spokes 8 and two top spokes 10 locate the magnet so that it's free to move up and down (as shown in the patent drawing, but there's a way to use it on it's side).

Spring Lifting System

The arms (14) are firmly attached to the magnet by a central rod.   Four triangular leaf springs (19) their base ends clamped to arms (14) and their pointed ends are linked (18)  to the pointed ends of the top springs (19).  There's a plate anchored to the frame (shown just above 26a) which holds brackets at the base of two of the top springs (19).  One of these is shown in the upper left of the drawing.  There are two Allan head screws that clamp the spring to the bracket (the upper left screw and another behind it not shown).  There are two pivot screws whose ends sit on the plate (above 26a) shown as the single screw to the right of the bracket.  The central screw goes through a clearance hole in the bracket and into a tapped hole in the plate.  These two screws have horizontal holes in the head so they can be adjusted from the side. 

Spring Lifting System - Not shown in patent drawing

Hilger Watts
              Seismometer Floating plate not shown in patent 3199072The other two top springs (19) are held by an identical pair of brackets, but instead of being connected to the plate (above 26a) they are connected to a plate that's been cut out of the first plate.  An an are bolted to the top of the plate (above 26a) and cantilevered out over the cut out section of plate.  In it's outer end there's a tapped hole.  The screw in that hole can be turned to cause the floating plate to move and this changes the tension of the spring system.  The screw can be accessed by removing the large headed screw that holds the cover over the clamping screw (22).  The highest dial setting that I can get to work in the vertical position is "18" and here the spring lifting system adjustment screw is backed out so that it's cantilevered is almost touching the floating plate.

Setting Period

If the dial associated with the period adjustment (knob at top left) is set to full CCW it stops at about 23.  But it's impossible using the spring lifting system screw to center the magnet (6) in it's range of travel.  This might require using a pin to adjust the other two screws or some other adjustment, or maybe it can't be done.  The resistor that caused critical damping when the dial was at 15 is much too weak when the dial is at 18 and the period is some number of seconds.  It takes a number of cycles of ringing until the mass stops.

If  you have any documentation on how to use this Hilger & Watts seismometer please let me know.


The three coil termination pairs have letters scratched in the phenolic.  Although there are positions for 6 output wires, on this unit only 4 are used.   The patent mentions that the damping needs to be adjusted for the selected period.   This unit has two separate coils, C-D (1k5 Ohms) and E-F (7k6 Ohms).  There is a brown jumper between D and E thus presenting the full coil between C and F (White and Yellow).  Connector pins B & F go to a pair of  wires terminated with a 6k7 Ohm resistor that I choose for best damping. 

The connector is marked in the center of the insulating block 148-CP  and has 6 male pins.  Threads for mating shell are 0.864" O.D.  mating insert OD less than 0.691" O.D. with a single grove for keying.


The dial calibrated from 0 to 25 which should change the period instead seems to move the mass up or down and when at 15 the rod in the height viewing dome is level with the center fiducial mark.  Moving this dial to either extreme bottoms the mass.

The label on the outside "1NS" implies this was used in the horizontal position.  But when placed horizontally the mass locks up.  So it's really not working correctly.  There is probably something that needs to be done to get proper operation when vertical, which is the position I'd like to use.

These look similar to the sensors used in the GR-8 Sound Ranging Set.

Patents by Willmore:

3199072 Variable Oscillation Period Seismometer, Patrick L. Willmore, Hilger & Watts, August 3, 1965, 367/185
3292145 Willmore Long Period Vertical Seismograph, Patrick L. Willmore
2909759 Sensitive Vertical Displacement Seismometer, George W. Cook, Oct 20 1959, 367/186 ; 327/518
2933715 Seismic Device, Beuermann (Firma Seismos, DE), Apr 19 1960, 367/184 ; 310/15; 310/27; 73/654 -
3297982 Horizontal seismometer
2939079 Method of Calibration an Electromagnetic Seismograph, Patrick L. Willmore

Kinemetrics (Wiki Support web page)

SH-1 Horizontal Seismometer

Fig 1
Kinemetrics SH-1 Horizontal Seismometer
Fig 2 FC-1 Field Calibrator

Kinemetrics FC-1 Field Calibrator

Cal Tech

Interesting photo from eBay of a vertical pendulum unit that is the SH-1 & label shows patent 3685011.

Cal Tech
              Horizontal Seismometer patent 3685011

3685011 Seismometer, Francis E. Lehner (Cal Tech), Aug 15 1972, 367/182 ; 73/654 - coil in magnet type with calibration pulse input, maybe 5 second period (adjustable).
3194060 Seismic Displacement Transducer, L.T. Greenwood (NASA), Jul 13 1965, 73/654 ; 367/179; 73/382R -
2074043 Seismograph, Louis Statbam (Std Oil), Mar 16, 1937, 367/182 ; 310/15; 73/654 - cylindrical package, down hole? permanent horseshoe magnets
2873103 Seismological Instruments, R.F. Hautly, Feb 10 1959, 73/653 ; 73/514.14; 73/650 - torsional damped limited frequency response reflecting mirror
1869828 Devices for Measuring and Recording Vibrations in Three Directions
2268526 galvanometer
2487793 Object Controlling Electric Motor System, (Sperry Gyro) - used as part of aircraft auto pilot
2542018 Compass, Ferrill (Sperry Corp), Jr. et al, Feb 10 1951, 33/360 ; 33/362; 33/363Q; 73/504.14 - vibratory compass
2552722 Electromagnetic Accelerometer, John G. King, May 15 1951, 73/514.12 ; 324/127; 33/DIG.5; 336/135; 336/30; 336/67; 336/92; 336/94; 340/870.35; 73/514.31- magnet if bob of pendulum
2616681 Angular Velocity Responsive Apparatus, C.T. Morrow (Sperry Corp), Nov 4 1952, - ref 2513340
2842752 Geophones, W.M. Jones (British Petrolum), Jly 8 1958, 367/182 ; 267/160; 336/100; 336/136
2852769 Time Interval Multiplier, R.L. Plouffe (Navy), Sep 16 1958, 342/186 ; 327/134; 327/172; 327/174; 368/115

3704764 Air deliverable seismic system,  Harold B Henderson, Texas Instruments Inc, Dec 5, 1972, - from patent number of a different seismometer on eBay.

FC-1 Field Calibrator

All the connections are on the front panel.
It appears the input is modified by a "Sensor" factor and an "acceleration" factor and an output results.

See photo above with SH-1 and SH-1 documents.

SMA-1 Seismograph


This is an early 3-axis seismograph (meaning it makes a physical graph, aka accelerograph, aka Wood-Anderson, Strong Motion Accelerometer (SMA).
Bulletin of the Seismological Society of America, Vol XV, March 1925, No. 1: Description and Theory of the Torsion Seismometer by Anderson & Wood.

CalTech CE-181: 4/14/204 Seismographic Systems.pdf "More than 10,000 SMA-1 series of accelerographs were manufactured by Kinemetrics in Pasadena from the late 1960’s to the mid 1990’s. This instrument also has a mirror that deflects in torsion. It’s natural frequency is about 30 Hz, and is also 70% damped.  At frequencies lower than 30 Hz, the records from this instrument are proportional to ground acceleration.  These instruments record on70 mm film and they only record when triggered by vertical accelerations that exceed about 1% g. The clip level on an SMA1 is about 1.5 g.  When the frequency of the signal exceeds 15 Hz, it is necessary to deconvolve the instrument response to obtain true ground acceleration from this instrument."
Nat. Freq

The USGS had all their SMA-1 units fitted with the WWVB time code option so that the exact time was recorded along with the 3-axis data. (Ref USGS report 1953-1995)


The heart of this device are three accelerometers where a mass and spring are damped by a coil moving over a magnetic rod.  The damping factor is set by choosing a fixed resistor to connect across the coil.  While the primary recording method relies on a mirror that's part of the moving mass and a spot of light is directed at 70mm film.  A secondary method amplifies, integrates and filters the voltage across the damping resistor and provides it as an electrical output.  I think these can be used without using the 70mm film.  Now looking for more technical information.

The P-wave trigger is adjustable between 0.005g to 0.05g.  An external trigger from all 3 axis is available.


3877296 Strong motion accelerograph with self-starter and electrical as well as light outputs, William Joseph Rihn, Kinemetrics Inc, 1975-04-15 - Strong Motion Accelerograph SMA-1 - contains a P-wave trigger to start the 3-channel recording and also as an output.

4028659 Strong motion accelerograph with self-starter and electrical as well as light outputs, William Joseph Rihn, Kinemetrics Inc, 1977-06-07 SMA-1 improvements

6363035 Seismic sensor having two symmetrical leaf springs and a method for detecting seismic movement, Eric L. Canuteson Guillermo D. Naranjo, Kinemetrics Inc, 2002-03-26 - to remove temperature sensitivity

6776042 Micro-machined accelerometer, William Thomas Pikeian, Maxwell Standley, Amadej Trnkoczy, Kinemetrics Inc, 2004-08-17

4028659, Kinemetrics Inc , 1975-04-15

Article: Cross-axis sensitivity of accelerographs with pendulum like Transducers-Mathematical Model and the Inverse Problem - Maria I Todorovska - USC
  • October 1998Earthquake Engineering & Structural Dynamics 27(10):1031 - 1051
  • DOI:  10.1002/(SICI)1096-9845(199810)27:10<1031::AID-EQE766>3.0.CO;2-1 Article 1998: Advanced sensitivity calibration of the Los Angeles strong motion array - Results are presented of recent sensitivity calibration of 76 accelerographs (SMA‐1) of the Los Angeles Strong Motion Array.


This geophone is from the PSR-1 Seismic Intrusion Detector set.

12.7 oz.

Quake Alarm

The Quake Alarm is just a simple brass rod pendulum whose lower end is in a triangular opening in a brass block.  The brass block can be moved in and out by means of the adjusting screw on the front thus changing the gap between the rod and block, i.e. the sensitivity.  BUT, this is not a P wave detector but rather a horizontal motion detector, not what I was looking for.
This one is made by jds Products andis their model QA-2000.

At a prior house I had a similar looking unit that was a true P wave (Wiki) detector to give earlier warning of a quake.

EarthQuake Alert

This is a P-wave (Wiki) detector that sounds a warning prior to the arrival of the S (shear) wave that has the high energy.  The p-wave is an up-down motion that arrives before the S-wave, where the time difference depends on the distanct to the epi center.  Not much warning if the quake is local, but a couple of minutes for someone in San Francisco during the 1989 Loma Prieta quake (Wiki).

Atomic Bomb Test Ban

By using a high dynamic range and wide bandwidth ( 10 seconds to 10 Hz) seismograph the difference between an earthquake and an explosion can be detected.  The Vela Uniform project (Wiki) investigated how to do this. Keywords: Long Range Seismic Measurements


1552186 Seismometer John A Anderson, Carnegie Institution, 1925-09-01, - optical spot projection, cited by 14 patents

1784415 Electrical Recording Seismograph, H. Benioff (Carnegie), Dec 9 1930, 340/870.16 ; 310/15; 340/870.31; 340/870.44; 346/107.1; 346/65; 367/179; 367/182; 73/654
Called By: 
2933715 Seismic Device,Beuermann, Apr 1960,
2269453 Device for Detecting Displacements, E.L. Gayhart, Jan 1942
2348225 Magnetic Seismometer, O.S. Petty, May 1944 - oil prospecting geophone
2576775 Seismometer System, F.D. Case (Diamond Inst), Nov 1951, - long period earthquake detection in small size
2683867 <See below>
2756406 Vibration Detector, G.S. Schurman (Calif. Research Inst), July 1956, - Frequency Response vs. Geophone mass - oil prospecting
2788512 Low Frequenc Seismometer, W.J. Reichert (Shell), April 9 1957,
2707776 Magnetron Type Seismometer, Cruzan (Phillips Petro), May 1955 -
2683867 Parachuted Radio Seismic Transducer, J.O. Vann (not assigned), July 13 1954, - for measuring polar ice
3225328 Transportable Seismograph, F Lecroart,

2096867 Low frequency oscillator with negligible resistance, Thompson Robert R, Standard Oil Dev Co, Oct 26, 1937, 333/186, 323/354, 331/154, 323/344, 336/136, 336/41 -  coil over magnet suspended by spring, very high Q
2111643 Seismometer, H. Salvatore (Western Geophysical Co), Mar 22 1938, - combine permanent magnets and coils - prospecting
Called by:
2418953 Transducing System, R.W. Raitt
2519916 Inertial Electromagnetic Throat Microphone, D.W. Martin (RCA),
2470244 ELECTRICAL REPRODUCING STYLUS - for machine shop duplicating
2562983 Frequency Adjustable Seismic Wave Detector, D.H. Clewell, Aug 7 1951, - oil prospecting
2643367 MAGNETOSTRICTION SEISMOMETER, (Phillips Petroleum Co)
2663088 Pendulum and Acceleration Compensation System, R.T. Cloud (N. Am Geo)
2671202 VIBRATION PICKUP, M.O. Petroff (Stewart-Warner), Mar 2 1954 - wheel balancing
2595067 INERTIA TYPE VIBRATORY PICKUP, J.A. Flint (Jeffrey Mfg), Apr 1952
2659065 SEISMOMETER, R.L. Cordell (Stanolind Oil)
3066526 UNBALANCE DETECTION APPARATUS, H.R. Tear (Stewart-Warner),- wheel balancing
3480808 POWER GENERATOR, F. Rieth (Packard-Bell) - probably for TV remote
4740775 Automobile burglar alarm, R. Price,
4584569 Motion sensitive security system, M.J. Lopez,
5323133 Method and apparatus for making electrical connection with a movable member, - loudspeaker

The above patents were found by looking for patents that are called by or call the Hilger & Watts patent.

2359245 Electrical displacement vibrometer, Gulf Research Development Co, Sep 26, 1944, 73/654, 367/178, 73/DIG.400, 340/870.16, 338/2, 381/162, 338/5, 338/43, 310/25
------------------ Korean Conflict-----------
2533249 Seismic Detector, December 12, 1950, 310/25 ; 367/183; 73/496
2636160 Vertical Component Low Frequency Geophone, April 21, 1953, 318/680
----------------- Korean Conflict end -----------
2696592 Vib Pickup, December 7, 1954, 336/30 ; 335/285; 336/100; 336/136; 336/90; 73/654
2745085 Seismic Detector, May 8, 1956, 367/185 ; 310/14
2748370 Seismometer, May 29, 1956, 367/187 ; 174/77R; 267/160
2751573 App Chg Reas Freq, June 19, 1956, 367/183 ; 310/25
coil current changes reas freq and can be done on whole string.
2753544 Seismic Detector, July 3, 1956, 367/182 ; 267/159; 310/25; 73/654
2754435 Voltage Generating Vibratory Pickup Devices, T. Ongaro, International R&D, July 10, 1956, 310/27 ; 367/183; 73/661
Machine Balancing or Monitoring
2756406 Vibration detector, Glenn A Schurman, California Research, 1956-07-24, 367/184 ; 310/15 - 14 citations:,
Publication number  Priority date  Publication date  Assignee  Title
US1271864A  1917-08-13  1918-07-09  Thomas J Digney  Submarine barrier.
US2013993A  1931-02-21  1935-09-10  Texas Co  Pneumatic vibration detector
US2038101A  1931-02-18  1936-04-21  Texas Co  Vibration detector
US2062784A  1932-04-04  1936-12-01  William G Green  Seismograph
US2074043A  1932-07-29  1937-03-16  Standard Oil Dev Co  Seismograph
US2130213A  1935-10-23  1938-09-13  Texas Co  Vibration detector
US2272984A  1939-07-21  1942-02-10  Gulf Research Development Co  Seismograph
US2304738A  1939-06-29  1942-12-08  Socony Vacuum Oil Co Inc  Seismograph
US2307792A  1939-07-28  1943-01-12  Cons Eng Corp  Seismometer
US2348225A  1940-02-13  1944-05-09  Olive S Petty  Magnetic seismometer
US2372056A  1941-06-21  1945-03-20  Socony Vacuum Oil Co Inc  Method and apparatus for recording seismic waves
US2371973A  1944-01-10  1945-03-20  Socony Vacuum Oil Co Inc  Geophysical prospecting apparatus
US2387223A  1943-02-06  1945-10-16  Research Corp  Vibration pickup
US2636160A  1949-08-29  1953-04-21  Socony Vacuum Oil Co Inc  Vertical component low-frequency geophone
2764019 Vib Meas Dev, September 25, 1956, 73/654 ; 310/27; 73/661
rectify AC output and drive a meter, no batteries machine monitor
2788510 Seismic Prospecting Apparatus, April 9, 1957, 367/86 ; 174/70S; 367/176
2788511 Frequency Seismometer, E.H. Marshall, Texas Inst, April 9, 1957, 367/187 ; 267/161, - oil exploration
2788512 Frequency Seismometer, April 9, 1957, 367/14
2788513 Cable, E.T. Howes, United Geophysical Corp, April 9, 1957, 367/180 ; 174/102SC; 174/106R; 174/27; 174/71R; 310/338; 310/357; 367/154
2842752 Geophones, July 8, 1958, 367/182 ; 267/160; 336/100; 336/136
2923367 M App for Seismic sur, February 2, 1960, 367/34 ; 367/48; 367/58
2933715 Geophones, April 19, 1960, 367/184 ; 310/15; 310/27; 73/654
2939079 METHOD OF CALIBRATING AN ELECTROMAGNETIC, May 31, 1960, 324/537 ; 324/202; 367/13
---------------- Vietnam Era ---------------
2980042 Method for Planting Seismic Detectors, B. McCollum, April 18, 1961, 405/177 ; 111/199; 111/89; 343/719; 405/175; 405/183 - oil exploration
3020767 Linear Accelerometer, W.P. Kistler, KistlerInst Corp., February 13, 1962, 73/497 ; 267/160
feedback provices linear, sensitive operation
3057209 Seismic Vibration Pickup Means, K.F. Frank, Micro Balancing Inc., October 9, 1962, 73/654 ; 336/40
dynamic balancing machine
3067404 Vibration Detector, A.B. Hilderbrandt, Jersey Prod Res, December 4, 1962, 367/182 ; 310/15; 310/27; 73/652
oil exploration
3119978 Device for connecting cables to geophones, Harold A Sears, Hall Sears, 1964-01-28, -
3199072 Variable Oscillation Period Seismometer, August 3, 1965, 367/185
Hilger & Watts earthquake type
3202847 Tunable Vibration Pickup Device, L.H. Erickson, August 24, 1965, 310/14 ; 310/15; 367/184; 73/654
alarm or balancing equipment, reasonant type
3212057 Long Period Seismometer, F.E. Romberg, Texas Inst, October 12, 1965, 367/184
portable horizontal period much longer than equivalent pendulum, not as sensitive to tilt (tolerates 0.5 deg).
aimed at nuclear detection
3241375 Transducer, R.M. Canzoneri, Consolidated Electrodynamics Corp., August 24, 1965, 310/14 ; 310/15; 367/184; 73/654 - strain gauge type, instrumentation, tolerates hi G
3281543 Calibrator for microphones, Haile S Clay, Charles W Cantoni, Donald B Ricketts, GTE Sylvania, 1966-10-25, -"Geologists, seismologists, and petroleum and research engineers use acoustical data...", 0.1 to 20 Hz acoustic, not vibration - What microphone would this be for??? let me know (PS GTE in Mountain View) Guess:  Nuclear Test Ban monitoring, infrasound
3296587 Intrusion detector system, Buford M Baker, TI, App: 1963-02-20, Pub: 1967-01-03 - See PSR-1 Patent
3451040 Spring Suspension for Low Frequency Geophone, W.P. Johnson III, Mark Products,  June 17, 1969, 367/183 oil exploration - Sercel/Mark Products: L-4 is marked with this number
5,500 Ohms, 1 Hz, 45 dynes/Amp, 972 grams i.e. L-4C.  They also make geophone testers.
25Jun22-eBay: Mark Products L-4 | 500 Ohms | 1.0 Hz | 956.1 gm | Seismometer Sensor, Sercel\Seismometers - Geophones_brochure_Sercel_EN.pdfGeophones_specifications_Sercel_EN.pdf -

L-4 is an instrument quality 1-hz or 2-hz multi-purpose seismometer that is small, light, and economical. It is designed to yield the performance needed for scientific studies, yet has the ruggedness required for petroleum exploration work.

The L-22 miniature low frequency land seismometer is available in 2.0 hz models, and may be obtained with several different coil resistances as standard manufacture. Other coil values are available on special order.

Geophone Tester Related Patents

2597005 Method of calibrating microphones, James M Kendall, Geophysical Res Corp, 1952-05-20, 73/1.83; 324/202; 367/141; 367/13; 381/58 - hydrophones
2923366 Seismic prospecting method, Edwin P Meiners, Glenn A Schurman, California Res, 1960-02-02, 367/37; 367/189; 367/180 -
3224246 Low frequency hydrophone calibration, Schloss Fred, Strasberg Murray, 1965-12-21, 73/1.83; 367/13 - pressure tank + shaker moves tank up/down
3744294 Acoustical transducer calibrating system and apparatus, T Lewis, R Cohn, NASA, 1973-07-10, 73/1.82; 381/150; 367/13 - air pressure for aircraft measurements
3858169 Geophone impulse tester, T Bardeen, Gulf Res, 1974-12-31, 367/140; 367/13; 367/58; 73/1.85 - applying an electrical impulse to a single sensor or string of sensors.
4441173 Very low frequency hydrophone calibration, James F. McEachern, US Navy, 1984-04-03, 367/13; 73/1.83 - motor makes LF waves
4909064 Impulse calibration of mechanical to electrical transducers, Richard D. Talmadge, US AF, 1990-03-20, 73/1.82 - hammer taps sensor
3545286 Holder which is Displaceable Along one Axis, L.A. Stenstrom, Philips, December 8, 1970, 248/604 ; 267/154; 267/160; 73/514.24; 73/654
3577184 Low Distortion Seismometer, W.O. McNeel, Geo Space Corp., May 4, 1971, 525/342 ; 525/332.9; 525/333.1; 525/333.2; 525/359.1; 525/359.3; 525/359.5; 525/359.6; 525/361; 526/240
oil exploration
3582874 Electrodynamic Seismic Receiver, N.E. Fedoseenko, June 1, 1971, 206/6.1 ; 206/366
oil exploration
3582875 Geophone Device, S.H. Van Wambeck, June 1, 1971, 206/433 ; 229/120.23; 229/120.27
oil exploration
3609674 Seismometer, S. Hansen, Hughes Aircraft Co., September 28, 1971, 65/135.7 ; 373/27; 65/136.4; 65/324; 65/327; 65/347; 65/356 - bubble movement is sensed and a PID feedback loop provides wide bandwidth
3662326 Subaudible frequency detection system, Paul S Dennis Jr, (BAE) Hazeltine, App: 1969-11-04, Pub: 1972-05-09, - for making geophone output of person walking audiable
3738445 Seismometer Spring Suspension System, Wilson,
3742441 Seismometer, T Riley, Mark Products, App: 1970-03-25, Pub: 1973-06-26, - lower distortion
---------------- Vietnam Era ends---------------
4043175 Automatic method and apparatus for digitally indicating response characteristics of geophones of a geophysical data acquisition system 4259563 Method for dynamically tuning a seismic transducer
4323994 Geophone Spring, J.M. Coogler, Geosource, April 6, 1982, 367/183 ; 267/158; 267/161; 367/187
4458344 Tapered Geophone SpringJ.M. Coogler, Geosource, July 3, 1984, 367/183 ; 267/161; 367/187
4623991 Delta Shaped Geophone Spring, F.A. Vitringa, Geosource, November 18, 1986, 367/183 ; 267/161; 367/187
5113375 Method and apparatus for testing geophones
5134593 Geophone Spring, R.M. Logan, Western Atlas Intl Inc., July 28, 1992, 367/187 ; 267/141.3; 367/183
6658362 Method and apparatus for testing components
6816434 Seismic detection
WO2014015271 Micro-geophone, Daniel Woo, Geospace Technologies, 2014-01-23, -

Warning Alarm Patents

540 Subclass 540 indent level is 1 Specific condition
686.1 Subclass 686.1 indent level is 2 Position responsive
690 Subclass 690 indent level is 3 Geophysical (e.g., fault slip)

4689997 Motion detector suitable for detecting earthquakes and the like, September 1987, 73/652 ; 181/122; 340/580; 340/690; 367/182; 73/654
5633463 Earthquake detector, May 1997, 73/654 ; 181/122; 200/61.45R; 340/690; 367/182 - all mechanical
5837951 Inertia switching device, acceleration responsive device and method of  Making Acceleration Responsive Device, November 1998, 200/61.45R - ball in cage switch
6121888 Earthquake detector, September 2000, 340/690 ; 340/540; 340/686.1 - long spring sensor/switch
2689341 SAFETY DEVICE FOR INDICATING SHIFTING September 1954 340/690 ; 200/51.11; 200/61.45R
4262289 Seismic tremor sensor alarm April 1981 340/690 ; 200/61.51; 74/89.14; 74/89.1
4297690 Earthquake alarm system October 1981 340/690 ; 200/61.49; 200/61.51; 340/669; 340/689
4359722 Earthquake detection system with pendulum switch November 1982 340/540 ; 307/117
4484186 Earthquake indicator November 1984 340/689 ; 116/303; 200/61.52; 33/391; 33/402; 340/690; 73/652
4689997 Motion detector suitable for detecting earthquakes and the like September 1987 73/652 ; 181/122; 340/580; 340/690; 367/182; 73/65
4801793 Orientation indicating device (camera portrait or landscape)
January 1989 396/50 ; 396/287
4945347 Motion and orientation responsive device for seismic, intrusion, and tilt July 1990 340/689 ; 200/61.45R; 340/690     like Quake Alarm
4978948 Combined earthquake sensor and night light December 1990 340/690 ; 340/321; 362/253; 362/806
5418523 Earthquake motion detector alarm May 1995 340/690 ; 200/61.45R; 200/61.51; 340/66
5596183 Seismically activated appliance switch January 1997 200/61.45R ; 200/61.48; 200/61.51; 307/117; 340/690
5633463 Earthquake detector, May 1997 73/654 ; 181/122; 200/61.45R; 340/690; 367/182
5644300 Seismoscopic detector July 1997 340/690 ; 340/540; 340/691.5; 340/693.5
5867099  ----- bad patent no.------
February 1999
5929767 Earthquake detector and alarm July 1999 340/690 ; 200/61.45R; 340/601; 340/689

6459379 Earthquake-alarm device, October 2002, 340/601 ; 200/61.52; 200/DIG.20; 340/689; 340/690; 340/691.1; 340/693.5; 702/15; 73/649 - like Quake Alarm
7006000 Earthquake detecting and warning device, February 28, 2006, 340/690 ; 200/61.52; 73/579; 73/594; 73/649; 73/658 - inverted bowl

Seismograph Service Corporation (patents)

The TAGS Ship: How Did Lorac Work? - AN/SRN-7
2493534 Testing device for seismic signal apparatus, James E Hawkins, Seismograph Service Corp, App: 1947-06-13, Pub: 1950-01-03, -
2648979 Transducer testing apparatus, Jesse R Cornett, Seismograph Service Corp, App: 1946-08-09, Pub: 1953-08-18, -
2757750 Apparatus for generating seismic waves, James E Hawkins, William E Pugh, Seismograph Service Corp, App: 1948-10-08, Pub: 1956-08-07, -

2513314 Geophysical prospecting system, James E Hawkins, Seismograph Service Corp, 1950-07-04, - LORAC positioning system
2513315 Radio position determining system, James E Hawkins, Seismograph Service Corp, 1950-07-04, - LORAC positioning system
2513316 Radio survey system, James E Hawkins, Seismograph Service Corp, 1950-07-04, - LORAC positioning system
2513317 Radio position determining system, James E Hawkins, Seismograph Service Corp, 1950-07-04, - LORAC positioning system
2513318 Radio position finding system, James E Hawkins, Seismograph Service Corp, 1950-07-04, - LORAC positioning system
2513319 Geophysical prospecting system, James E Hawkins, Seismograph Service Corp, 1950-07-04, - LORAC positioning system
2513320 Radio position determining system, James E Hawkins, Seismograph Service Corp, 1950-07-04, - LORAC positioning system
2513321 Radio location system, James E Hawkins, Seismograph Service Corp, 1950-07-04, - LORAC positioning system
2513322 Radio location system, James E Hawkins, Seismograph Service Corp, 1950-07-04, - LORAC positioning system

2652558 Radio location system, James E Hawkins, Seismograph Service Corp,1953-09-15, - LORAC positioning system
2652559 Radio location system, James E Hawkins, Seismograph Service Corp,1953-09-15, - LORAC positioning system
2652560 Radio location system, James E Hawkins, Seismograph Service Corp,1953-09-15, -LORAC positioning system
2652561 Radio location system, James E Hawkins, Seismograph Service Corp, 1953-09-15, -LORAC positioning system
2652562 Radio location system, James E Hawkins, Seismograph Service Corp, 1953-09-15, - LORAC positioning system

Earthquake Early Warning

USGS April 2012 talk - by using a network of sensors the warning time can be maybe twice what you can get from an on site P-wave detector.

Earthquake Hazards Program

California Integrated Seismic Network - Earthquake Early Warning -

Quake-Catcher Network

They also has an Android app that uses the 3-axis g sensor combined with the magnet compass when the phone is sitting unused on the charger to report quakes.
This is better than the USB hardware which should be oriented to magnetic North.

Quake-Catcher USB
                    Network Seismometer

In the padded envelope you get:
* The seismometer,
* a couple of mounting wood screws
* a USB-A male to USB-B male cable
* one page of instructions.

On order is a pair of USB to CAT-5 LAN
adapters which should allow making a USB
extension cable over CAT-5 cable.

Also on order is a 100 foot CAT-5 LAN cable.

For $50 you can have  your own USB seismometer connected to the internet.
The sensor contains a 3-axis MEMS accelerometer and a USB interface.


ONavi B 16 bit.
The QCNLive display of the 3 sensor outputs does auto scale, so there should be some benefit from mounting the sensor away from the house.

USB-CAT5 adapters & 100" CAT5 cable

This does not work.  Why? Ans: handshake timing limits cable length.  But, an active USB extension cable does work and these could be cascaded.

1. can the USB cable be extended say 100 feet to allow sensor location far from the house?
2. does the software contain a circular memory so that the data can be uploaded at a later time if there's a network problem in real time?
3. Is there any intelligence in the sensor, i.e. a micro controller?
4. Is there provision for adding different sensors, like those on this page? Yes & No.  There's a list of supported sensors, but they are all USB based.  There's not provision for a 2-wire input type sensor like the Hilger-Watts.


There are three programs that need to be downloaded and installed (Instructions)

  • Boinc (Berkeley Open Infrastructure for Network Computing)- allows your computer to talk to the server over your internet connection.
    Add QCN to “My Projects”:
Select “Add Project” (Lower Right).
Select “Next”.
Under “Project URL” type the following:
USB driver for the specific sensor you have
QCNLive - program running on your computer
File\Local Settings - Lat, Lon, Ele, etc.

Windows Firewall needs to have Boinc added as an exception.


Earthquake 25 Sep 2012 8:15 am Ukiah

The electronic equipment was swaying North-South and it almost fell over.
Very strong shaking.
USGS web page.  M4.5

              25 Sep 2012 8:15 am Ukiah


Outdoor Intrusion Detectors and Related Equipment (most seismic, magnetic and/or Doppler)
GEO_ID - TRC-3, PEWS, USQ-42, Turd
GSQ154 - All GSQ-154
GSQ160 - Frequency Disconnect -GSQ-160, USQ-46, TS-2963, PP-6446 - TCw - cylindrical module pinouts.
GSS26 - AN/GSS-26 minimal info
Intrusion Alarm Patents
USQ_Rx - Igloo White, USQ-42, USQ-46 details,
PSR-1 - Seismic intrusion detector with audio output
Modular Outdoor Intrusion Sensors (REMBASS?)
Sonobuoy Based Outdoor Intrusion Sensors & Sonobuoies - CRT-1B Sonobuoy (hydrophone depends on Magnetostriction) - Roswell Connection



Spark Museum: Other Scientific & Philosophical  Apparatus -
Yuma-2 Force Balance Vertical (FBV) Seismometer Project - includes link to current data.
Brooke's: PRC68, Alphanumeric Index of web pages, ContactSensors,  Page
-  page created 22 July 2007.