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Topic: Geophone

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	Tutorial on Geophone Setting (Site not responding. Last check: 2007-10-14)
		In deciding where to plant the geophone, don't forget that the wavelengths of the waves analyzed by almost all surveys is 10 meters or longer.
		Press the geophone spike into the bottom of the hole, by hand or gently with a boot heel.
		Always connect the geophone to the cable takeout at the same time you bury the geophone.
	www.seismo.unr.edu /vs/geophone.html (439 words)

	Digital geophone system - Patent 4320472 (Site not responding. Last check: 2007-10-14)
		When the geophones are in use, the input/output switches IOTS are normally in their inputting state so that signals transmitted to the geophones from the electrical equipment EQ over the common conductor cable CCA may be transferred into the electrical unit within all of the geophones simultaneously.
		The voltages from the geophone are applied to the univibrators UVA and UVB to cause the univibrators to generate pulses of different durations depending upon the amplitude of the incoming seismic wave.
		Thus, in each geophone a synchronizer SNC is employed which responds to incoming pulses from terminal INT to cause the clock pulse generator CLPG to issue pulses to the gate CLG synchronously with the receipt of the pulses of the interrogate signal TRS by the geophone GE from the common cable CCA.
	www.freepatentsonline.com /4320472.html (14490 words)

	Refraction Geophone Cluster Test
		Since the size of the geophone cluster is much less than the seismic wavelengths at any frequency of interest here, the record from every geophone should be exactly the same.
		The geophone 25-48 records clearly contain a sign-reversed trace; this is due to a cable connector reversal and does not affect relative frequency response.
		Given the small size and mass of the geophones, their shallow burial and 8 Hz principal frequency, and the 4 Hz lower limit on the pre-amp low-cut filter, the spectral content of the data must be demonstrated.
	www.seismo.unr.edu /ftp/pub/louie/reno/clts/clts.html (1585 words)

	Combination geophone-hydrophone - Patent 4134097
		In particular, the geophone is rigidly mounted in the housing so that the velocity of the housing will be detected by the geophone while the hydrophone is mounted so that the housing may be buried in a solid material.
		The lower geophone housing 11 should be constructed of suitable material, such as brass or aluminum, and made sufficiently rugged to prevent physical damage to the geophone when the complete housing is buried.
		The geophone 14 is disposed in a recess formed in the housing and securely fastened to the housing by a combination of epoxy cement and cap member 15 which threads into the upper end of the geophone housing.
	www.freepatentsonline.com /4134097.html (2797 words)

	Geophone Research
		Geophones are highly sensitive ground motion transducers that have been used by seismologists and geophysicists for decades.
		Figure 1 shows both an isometric and cross-sectional view of a geophone, which uses the motion of a spring supported coil in the field of a permanent magnet to generate an output signal.
		A typical geophone, such as the OYO Geospace GS-11D used in many of our group's measurements, costs $50, has a resonant frequency of 4.5 Hz, a proof mass of 23 grams, and a peak sensitivity of 20 V/g.
	micromachine.stanford.edu /smssl/projects/Geophones (713 words)

	GEOPHONES page1 (Site not responding. Last check: 2007-10-14)
		Geophone specification have been published as soon as geophones where manufactured, and a large amount of documentation supplied to the users is probably lost today or difficult to unearth.
		To give to the actual user an efficient tool which allows him to retrieve the specification of any geophone, to compare their specifications or to plot their different characteristic, a computer program has to be available.
		Also it is possible to represent the characteristic of a string of geophone or the seismic trace itself grouping several strings to check the compatibility with the input circuit of the seismic recorder.
	members.aol.com /geophones/geo1A.htm (215 words)

	Seismic Transducers for FWD deflections
		Furthermore, Dynatest has developed a (proprietary) method of processing (within a fraction of a second) a sampled and digitized geophone signal time history in such a manner that each and every sample is corrected for the "distortion" created by the movement of the seismic mass during as well as after the FWD impact.
		Dynatest often uses the name "deflector" to indicate that it is not "just" a geophone, but a geophone combined with the above mentioned signal processing technique.
		It is hoped that this paper has made it clear that monitoring of FWD deflections is not a simple matter, and that a rather sophisticated signal processing and compensation technique is required to obtain a high accuracy, in particular if independence of loading time and validity of full time history data is considered important.
	www.dynatest.com /gallery/papers/seismic4.htm (406 words)

	A three channel geophone amplifier
		Each of the three geophones can be seen quite easily - they are mounted so that each of the geophones is aligned with the X, Y and Z axes.
		On top of the Z geophone the damping resistor can be seen - this resistor is used to damp the geophone membrane after being excited by a seismic wave reaching the instrument.
		Unfortunately (due to the quite high resonance frequency) geophones like this one can be used only to measure local seismic events since high frequency parts of seismic waves as generated by teleseismic events are filtered away by the earth itself.
	www.vaxman.de /projects/geophon_amplifier/geophon_amplifier.html (362 words)

	Geophone -- Encyclopædia Britannica
		Sources and Geophones are essentially the same as those used in refraction methods.
		The concept is similar to echo sounding: seismic waves are reflected at interfaces where rock properties change and the round-trip travel time, together with velocity information, gives the distance to the interface.
		The seismic wave is detected by a Geophone on land or by a hydrophone in...
	www.britannica.com /eb/article-9036478?tocId=9036478 (463 words)

	Mechanical Cardiography using a Geophone
		It is shown that a commercial geophone of the type used for oil prospecting may be useful for heart diagnostics, when connected to a personal computer through a user-friendly though powerful analog to digital converter with associated processing software.
		These were collected with the subject either (i) lying on the floor with the geophone resting vertically on the chest in the vicinity of the heart, or (ii) sitting with the geophone resting in a shirt pocket in the vicinity of the heart.
		As a seismic unit, the geophone responds to acceleration of the chest.
	physics.mercer.edu /petepag/cardio.html (864 words)

	Oilfield Glossary: Term 'geophone'
		A device used in surface seismic acquisition, both onshore and on the seabed offshore, that detects ground velocity produced by seismic waves and transforms the motion into electrical impulses.
		Conventional seismic surveys on land use one geophone per receiver location to detect motion in the vertical direction.
		Three mutually orthogonal geophones are typically used in combination to collect 3C seismic data.
	www.glossary.oilfield.slb.com /Display.cfm?Term=geophone (137 words)

	Web Service - Reverse Phone Number Append
		Service Objects' DOTS GeoPhone is a hosted, programmable XML Web Service that allows you to lookup name and postal address information for virtually every U.S. telephone number.
		DOTS GeoPhone is a multi-database XML Web Service designed to provide the most accurate reverse-lookup of residential and business telephone numbers available.
		DOTS GeoPhone is compatible with existing application development technologies, and is based on industry standards such as XML, SOAP, and WSDL.
	www.serviceobjects.com /products/dots_geophone.asp (282 words)

	Geostuff wall-lock borehole geophones (Site not responding. Last check: 2007-10-14)
		Geophone elements are available with 10, 14, 28 or 40 Hz natural frequencies.
		This unit is also available as the BHG-2C with a flux-gate compass which will indicate the orientation of the geophone in the hole (except for steel-cased holes).
		The clamping mechanism is operated by a DC motor, actuated by power sent down two of the conductors.
	www.georadar.com /geophone.htm (421 words)

	Separability in shot-geophone space
		One can imagine the appearance of the data that would result if the data were generated and recorded at depth, that is, with deeply buried shots and geophones.
		Such buried data could be synthesized from surface data by first downward extrapolating the geophones, then using the reciprocal principle to interchange sources and receivers, and finally downward extrapolating the surface shots (now the receivers).
		The shot coordinate s and the geophone coordinate g are independent variables, so the two square-root operators commute.
	sepwww.stanford.edu /sep/prof/bei/fdm/paper_html/node39.html (253 words)

	Geophone Based Intrusion Detectors
		By using a number of geophones (earth microphones) and listening to the sub sonic sounds they can make a sub surface map of the rock formations that may help in locating oil.
		The early air dropped seismic sensors were based on sonobouys with the hydrophone replaced by a geophone.
		This is a Viet Nam era fake turd that has mercury batteries a vibration sensor (not a geophone) and a transmitter.
	www.pacificsites.com /~brooke/GSQ160/Geo_ID.shtml (1665 words)

	A041 / A042 Side Wall Clamping Geophone Tools (Site not responding. Last check: 2007-10-14)
		The pulse propagates to a geophone detector or detectors placed at a known depth in the borehole.
		A Vertical Seismic Profile (VSP) is produced by measuring the elapsed time for the pulse from the source to the geophone(s) while capturing the complete wave train.
		Triaxial downhole geophones allow the recording of both shear and compression signals.
	www.auslog.com.au /austools/A041-42.html (264 words)

	GEOPHONE FAQ
		A geophone is a small, cheap instrument for measuring ground motion.
		The exterior case is optional on a lot of geophones.
		It's not a typical geophone with a coil and a magnet.
	www.tenrats.org /geo.shtml (510 words)

	Development and testing of a 0.5-inch microhole geophone package
		Borehole testing of conventional borehole geophones, microgeophones, and cemented-in geophones indicates qualitatively comparable performances for early arriving seismic energy from explosive shots in a neighboring well.
		Signals were acquired (i) using a conventional 1-11/16 inch slim hole geophone package (SHGP) in 4-1/2-inch casing free of any tubing; (ii) using the SHGP inside of the production tubing which itself was inside of casing; (iii) using geophones cemented in a nearby well; and (iv) using a microtool containing only vertical geophones.
		Figure 6 shows a spectral comparison between the microgeophone package and the cemented-in geophones in which the respective spectrum of each is normalized to its peak frequency amplitude.
	www.ees.lanl.gov /EES4/microhole/seg98.html (1483 words)

	Geostuff Home Page (Site not responding. Last check: 2007-10-14)
		A Borehole Geophone is a particular type of vibration detector for seismic waves--one that is designed to be used in a hole drilled in the ground.
		A wall-lock geophone is one designed to clamp the phone against the side of the borehole wall, usually so that S-waves or shear waves can be recorded.
		A Rollalong Switch is used in exploration seismology to select a group of geophones from a longer array placed on the ground surface.
	www.Geostuff.com (203 words)

	Geophone Wall Mount Kit - Installation Guide (Site not responding. Last check: 2007-10-14)
		Using the Geophone Wall Mount as a template, orient the block as shown, and mark the location of the two holes to be drilled.
		Remove the Geophone Wall Mount, and drill two 12mm (.47 inch) diameter holes; drill the holes to a depth of 89mm (3.50 inches).
		Position the Geophone (not included in this kit) on top of the Geophone Wall Mount, aligning the through-hole of the geophone with the mount; secure it using the bolt, washer, and wing nut.
	www.instantel.com /tech_tips/tip_geophonewallmount.htm (227 words)

	GEOPHONE (Site not responding. Last check: 2007-10-14)
		Specialty definitions using "GEOPHONE": electromagnetic geophone ♦ seismic record, seismic recording, seismic spread, seismogram synthesis, seismometer spread, seismometre spread.
		Geophon (geotector, seismograph, seismometer), Erdhörer (geotector, seismograph, seismometer).
		"GEOPHONE" is suggested in spellcheckers for the following: egophony, Egothon, Gecophone, Geoprobe, Neophane, Xephon.
	www.websters-online-dictionary.org /definition/GEOPHONE (307 words)

	Geophone - Wikipedia, the free encyclopedia (Site not responding. Last check: 2007-10-14)
		The deviation of this measured voltage from the base line is called the seismic response and analysed for structure of the earth.
		Geophones can be both digital and analog but the preference is towards digital phones these days.
		This page was last modified 02:17, 13 October 2005.
	en.wikipedia.org /wiki/Geophone (119 words)

	Note on use of a Sofar geophone to determine seismicity of regional oceanic areas -- Shurbet 52 (3): 689 -- Bulletin of ...
		Daily Bermuda short period seismograms are compared with Sofar geophone records for a period of 3 years.
		Many short-period seismic signals were recorded on the geophone record that are not on the seismograms.
		Therefore, it is suggested that a geophone array could be most useful in determining regional seismicity in oceanic areas, The large number of geophone signals recorded gives some indication that the advantages of the expected quiet of the ocean bottom may be somewhat offset.
	bssa.geoscienceworld.org /cgi/content/abstract/52/3/689 (153 words)

	Single Sensors vs. Arrays
		Single 3C MEMS (I/O VectorSeis®) sensors were deployed at the center of six-element conventional 1C geophone arrays at 1280 receiver stations within the project area.
		In this example, we conclude that P-wave data acquired using single MEMS sensors is viable, and that the resulting data are comparable to conventional geophone array data where short linear or circular arrays are used.
		Receiver stations (N-S) have a co-located single MEMS sensor (Sercel DSU3) and a conventional 6-element 1C geophone array; DSU3 sensors are also deployed on the half-station of the embedded test.
	www.veritasdgc.com /bins/content_page.asp?cid=4-1502-2105&print=true (550 words)

	Air-noise reduction on geophone data using microphone records
		This paper proposes using microphone recordings of air waves, recorded close to a geophone, to suppress air-wave noise on the geophone.
		The types of air-wave noise on the geophone may include air-coupled ground roll, air blast, ground-coupled air blast, and wind noise.
		I propose designing a geophone with an attached microphone to reduce noise on the geophone data.
	www.crewes.org /Reports/1998/1998-05.html (133 words)

	GEOPHONES (Site not responding. Last check: 2007-10-14)
		At the moment I am using the standard rotating drum, paper and ink pen seismograph with a short period horizontal seismometer orientated E-W. The seismometer is a 'Mark Products' L15BH geophone resonant at ~4.5 Hz and is potted in a 0.5m length of pvc tubing.
		A long period horizontal seismometer will also be added to the system as time permits and this will greatly enhance the recording of the large distant events.
		This is a view of the Geo-Space, 4.5Hz, 4000 Ohm coil, geophone seismometers that I use for my E/W, N/S and VERT.
	www.seismicnet.com /dave/g_phones.htm (329 words)

	Business Wire: Radix Announces Results of Geolocation Trial of... @ HighBeam Research (Site not responding. Last check: 2007-10-14)
		The GeoPhone System is a Time Difference Of Arrival (TDOA) network-based system that consists of sensor units to be co-located at each base station, and a central workstation co-located with the Mobile Switching Center (MSC).
		In addition to the low-cost, highly integrated sensor units, the GeoPhone System uses the existing wireless system antenna array, and the existing communications backhaul network of the wireless system to keep overall system implementation costs low.
		The GeoPhone System will be available in production quantities in both a CDMA only version and a CDMA-AMPS version by the fourth quarter of 2000.
	www.highbeam.com /library/doc0.asp?docid=1G1:62664514&refid=ink_tptd_g1 (627 words)

	Thumper/Geophone Experiment
		John is putting the geophone anchor in the ground about eight feet north of the Central Station, as per CDR-26 and CDR-27.
		The pre-arrival noise at the left side of the figure is not indicative of the true noise level because it includes residuals from prior shots and the crews movements between shots.
		As per CDR-28, he will align it with the geophone line and read off a sun angle which he will then use to properly align the base under the mortar package.
	history.nasa.gov /alsj/a16/a16.thumper.html (10857 words)

	The DSR equation in shot-geophone space
		Both (8) and (9) require minus signs because the travel time decreases as either geophones or shots move down.
		One is the cosine of the arrival angle at the geophones divided by the velocity at the geophones.
		It might be more descriptive to call it the survey-sinking equation since it pushes geophones and shots downward together.
	sepwww.stanford.edu /sep/prof/toc_html/bei/sg/paper_html/node11.html (263 words)

	Hydrocarbons Technology - CREATECH INDUSTRIE - Down-Hole Permanent and Semi-Permanent Geophone Arrays and Micro-Seismic ... (Site not responding. Last check: 2007-10-14)
		Its activities include the design and manufacturing of hostile environment equipment: down-hole permanent geophone arrays and pressure gauges, well seismic, production logging tools, micro-seismic monitoring systems, deep sea-bed geotechnical tools and specific equipment for the oil and gas industry.
		The geophone assembly, mounted on anchoring bow spring blade, is free from tubing weight and isolated from the tubing noise thanks to dampers.
		With a compact and light design, wire line type geophones are deployed in observation or treatment wells.
	www.hydrocarbons-technology.com /contractors/exploration/createch (696 words)

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