Abstract: Apparatus and method for determining the location of the source of seismic energy around a well are provided. Multiple seismic receivers, each receiver having orthogonal seismic sensors, are axially spaced on a tool which is capable of sending real-time seismic signals to the surface over conventional wireline. A method for calculating the location with respect to the receivers is also provided, the method employing data from all the sensors and a performance function to minimize error in the determination of location, and a simplified method is provided for determining if a fracture has extended past a selected depth in a formation.

Abstract: A dipole acoustic well logging instrument including an acoustic transmitter. Receiver sections are disposed at axially spaced apart locations from the acoustic transmitter. Each receiver section includes an outer shoulder at each end adapted to be placed in acoustically isolated contact with an internal shoulder of a connector coupling when the instrument is in tension. The outer shoulders have an acoustically isolating material disposed on their surfaces. The receiver sections include an inner shoulder at each end adapted to be placed in direct contact with an external shoulder of the connector coupling when the instrument is in compression. The instrument includes one connector couplings disposed at each end of each receiver section to couple the receiver sections to each other and to the remainder of the instrument. At least one receiver element is disposed in a passage formed into each of the receiver sections.

Abstract: An underwater sensing device for measuring or sensing an underwater condin proximate the floor of an ocean, lake or similar body of water. The sensing device includes an underwater sensing device mounting member and an underwater sensing device sensor, such as a hydrophone, mounted on the mounting member. The mounting member has known acoustic properties including a thickness and a largest dimension, each of which is a function of an acoustic wavelength in the underwater environment. The sensing device can also include acoustic diffraction reducing members disposed around the edges of the mounting member. The sensing device can also include first and second underwater sensors disposed on either side of the mounting member so that one of the sensors faces away from the underwater floor. An underwater sensing device switch, such as a gravity switch, activates the sensor that faces away from the underwater floor.

Abstract: An earthquake detector including a platform fixedly coupleable to a recipient surface for receiving vibrations generated as a result of an earthquake; a spring-loaded frame secured to the platform; an alarm mechanism coupled to the spring-loaded frame for providing an alarm when the platform and frame are shaken; and a counterweight coupled to the frame for damping its vibration.

Abstract: The objective of this invention is to simplify and provide a versatile device capable of accurately measuring seismic activity. The technique is based on magnetic levitation. The concept of magnetic levitation has been around since the 1960's, and it has been used extensively for high speed trains, however its use in seismology has been described in U.S. Pat No. 3,626,364 issued to Simon et al. However the present invention utilizes a four-vector magnetic field instead of three separate scalar magnetic fields. The advantages of present approach is reduction of three seismic masses to a single seismic mass.To detect seismic activity using this concept, a seismic mass must be magnetically suspended. A seismic mass trapped in a magnetic field still possesses its inertia. Therefore, as the magnetic field moves under the influence of seismic activity, the seismic mass will tend to stay in the same place. The controller, however tends to keep the seismic mass in its place.

Abstract: A method for determining a unique signal representing the earth's response between a transmitter and receivers when conducting a seismic survey involves the steps of receiving a seismic signal set that comprises a plurality of different output frequency signals having known amplitude and phase characteristics, selectively combining the different output frequency signals to form the unique signal, and recording values of amplitude, phase, and frequency of the unigue signal. A method of conducting a modulated seismic survey involves the steps of providing seismic sensors capable of receiving a modulated seismic signal comprised of different frequency signals, transmitting modulated seismic energy information into the earth, and recording indications of reflected and refracted seismic waves sensed by the seismic sensors in response to transmission of the modulated seismic energy information into the earth.

Abstract: An inference device for discriminating an earthquake includes an ON/OFF signal generating means for generating an ON/OFF signal corresponding to an oscillatory wave, a characteristic parameter extracting means for extracting at least one of three characteristic parameters consisting of an ON period, an ON time sum total and a maximum ON time value based on the generated ON/OFF signal, and an inference means for inferring for each ON period based on the extracted characteristic parameter whether or not an earthquake happens.

Abstract: This invention provides a dual gimbal geophone assembly. The geophone is placed in the cavity of a mass member. The mass member is rotatably attached to a frame so that the mass member rotates about a first plane. The frame is rotatably attached to support members so that the frame rotates about a second plane which is orthogonal to the first plane. This geophone provides two degrees of rotation, one along the first plane and the second along the second orthogonal plane. The geophone remains vertical within the tilt tolerance of the geophone regardless of the orientation of the assembly.

Abstract: The device comprises instruments for collection and recording of signals in seismic exploration of the substratum off-shore. The device is designed as a pole which is adapted to be forced down into the seabed and comprises a pointed lower end (7), an intermediate approximately cylindrically shaped main portion (6), a vibration-absorbing spacer (14) between the pointed end (7) and the intermediate main portion (6). The other end of the intermediate main portion (6) is connected to a top part (8) designed for inserting/pulling and other ways of handling the device. The pointed end (7) at least comprises geophones (15-17) and a hydrophone (23) is placed in the vicinity of the upper end of the device. The majority of the device's other instruments are placed in the intermediate main portion (6). The device is connected to a main cable (4) which extends to a seismic ship (29, 31).

Abstract: A seismic switching device that has an input signal from an existing microseismic station seismometer and a signal from a strong motion measuring instrument. The seismic switch monitors the signal level of the strong motion instrument and passes the seismometer signal to the station data telemetry and recording systems. When the strong motion instrument signal level exceeds a user set threshold level, the seismometer signal is switched out and the strong motion signal is passed to the telemetry system. The amount of time the strong motion signal is passed before switching back to the seismometer signal is user controlled between 1 and 15 seconds. If the threshold level is exceeded during a switch time period, the length of time is extended from that instant by one user set time period.

Abstract: An earth movement sensor is provided which consists of a housing having a top shelf and an intermediate shelf. An electrically energizing signalling alarm is carried in the housing. An electrical power source is carried in the housing for the alarm. A pendulum operated switch is suspended from the top shelf in the housing and is operatively connected between the power source and the alarm, to energize the alarm from the power source when there is earth movement.

Abstract: A device detects seismic motion by linear motion of a seismic detection ball within an inner casing. Radial protrusions on the inside surface of a bottom wall of the inner casing maintain linear back-and-forth motion of the seismic detection ball while in contact with the casing bottom wall. On the inside surface of the perimeter wall of the inner casing, radially inward protrusions are formed parallel to one another to prevent rotation of the seismic detection ball in a circular path along the casing perimeter when it is lifted up from the casing bottom wall. The seismic detection ball is formed from a material unaffected by magnetic fields. The inner casing is suspended within an outer casing, in a condition of damped swaying. The inner casing is composed at least partially of a metallic material to provide sufficient weight to insure reliable automatic centering.

Abstract: An underwater probe for determining true acoustic intensity by the direct asurement of true acoustic velocity and true acoustic pressure in a neutrally buoyant package, utilizes a moving-coil geophone embedded in a casting of syntactic foam and a pair of hydrophones on the exterior of the casting.

Abstract: A self-orienting seismic detector for detecting vertical acceleration regardless of the device's horizontal orientation. The detector comprises a housing fitted with diaphragms capable of generating signals. A mass is internally suspended within the housing between the diaphragms by means of a filament which is connected at each of its ends to one of the diaphragms. Vertical motion of the detector causes internal displacement of the mass within the housing. Motion by the mass within the cylinder is translated by the filament to the diaphragms which generate signals which may then be recorded. The detector may be incorporated within or attached to an undersea cable to form a seismic detection system primarily suitable for placement on an ocean bottom, but which may be employed in a towed array. In a primary embodiment, the detector is sealed from external pressure changes such that the stresses placed upon the detector's diaphragms will be governed by particle acceleration changes rather than pressure changes.

Abstract: A lightning protection system is disclosed for a seismic data acquisition system having single or multiple geophones positioned at predetermined ground locations over a large area. A surge suppressor is placed across the leads to which the geophones strings are connected. Such surge suppressor preferably comprises a gas discharge arc tube. The base or spike of each geophone is implanted in the ground, A ground lead is connected to the surge suppressor. Electrical energy from a lightning strike affecting the geophones, cables, data acquisition boxes, etc. is dissipated by the surge suppressors through the multiple spikes to the earth thereby to minimize damage resulting from lightning.

Abstract: A seismic sensor platform comprises an open frame and a plurality of seismic motion sensors vertically positioned in a common horizontal plane in spaced relationship around the periphery of the open frame. A spike associated with each of the sensors extends beneath the open frame for anchoring each of the sensors in the earth. The frame includes a shield for protecting the sensors from physical damage and for shielding them from seismic noise. Second and third pluralities of horizontally positioned sensors may be provided on the frame, orthogonally positioned with respect to each other to sense orthogonal components of reflected seismic waves. The sensors may each be of a different natural frequency to optimize the multi frequency output of the sensor array.

Abstract: A remote seismic sensing system is provided which operates as a bipolarized, differential mode, LDI (laser differential interferometry) system to detect electrical signals produced at a remote location. In preferred embodiments, the system is used in seismic surveying to detect array signals. An amplified array signal (the electrical signal is coupled to an array retroreflector apparatus (target). The array signal is obtained from an array of seismic detectors, e.g., geophones or hydrophones. The amplified array signal increases the velocity of a Doppler shifting optical component on the target. The target converts a defused sensing beam into two polarized return sensing signals, both of the return sensing signals having been Doppler shifted by the target to contain frequency components that represent motions, e.g., ground motions and wind motions, that are common to both signals and to contain a difference signal which represents the array signal.

Abstract: A remote sensing system is provided which operates as a bipolarized, differential mode, LDI (laser differential interferometry) system to detect an electrical signal produced at a remote location. The system is adapted to reduce the effects of turbulence induced frequency fluctuations by using an array retroreflector apparatus which converts a single sensing beam into a single return beam having two, overlapping, transversely polarized sensing signals; thus, turbulence induced noise will be common mode to both return signals and cancel at the receiver.In preferred embodiments, the system is used to remotely detect an amplified array signal from a plurality of seismic detectors (e.g., geophones or hydrophones) connected to form an array at the remote location. The target is coupled to common motions at the selected location and the amplified array signal is coupled to an optical component within the target.

Abstract: In a preferred embodiment, an accelerometer sensor system, including: a housing structure; a first acceleration sensor disposed in the housing structure at a first selected location along the vertical axis of the housing structure, the first acceleration sensor providing a first output; a second acceleration sensor disposed in the housing structure at a second selected location along the vertical axis, the second acceleration sensor providing a second output; and apparatus to combine the first and second outputs of the first and second acceleration sensors such as to simulate the output from a virtual acceleration sensor located at any selected location on the vertical axis, allowing one to reduce noise induced by pitch motion, at any desired frequency or across a desired frequency band.

Abstract: A seismic detector for boreholes is described that has an accelerometer sensor block for sensing vibrations in geologic formations of the earth. The density of the seismic detector is approximately matched to the density of the formations in which the detector is utilized. A simple compass is used to orient the seismic detector. A large surface area shoe having a radius approximately equal to the radius of the borehole in which the seismic detector is located may be pushed against the side of the borehole by actuating cylinders contained in the seismic detector. Hydraulic drive of the cylinders is provided external to the detector. By using the large surface area wall-locking shoe, force holding the seismic detector in place is distributed over a larger area of the borehole wall thereby eliminating concentrated stresses.

Abstract: A remote sensing system is provided which operates as a bipolarized, differential mode, LDI (laser differential interferometry) system to detect motion at a remote location. The system is adapted to reduce the effects of turbulence induced frequency fluctuations by using a retroreflector apparatus which converts a single sensing beam into a single return beam having two overlapping transversely polarized sensing signals; thus, turbulence induced noise will be common mode to both return signals and cancel at the receiver. In preferred embodiments, the system is used to detect seismic motions. The retroreflector apparatus is coupled to ground motions at a selected location where it separates the sensing beam into two polarized sensing signals, frequency modulates one of the polarized sensing signals to contain frequency components that represent selected ground motions, and combines the polarized sensing signals into the return beam. The return beam is detected.

Abstract: A device including instruments for use on the seabed for the collection and recording of first signals during off-shore seismic exploration.

Abstract: The present invention is a multi-function earthquake alerting apparatus. It is designed and built as an average household item with simple and durable mechanical parts. It can serve as a decorative item. However, when an earthquake happens, it will serve as an information center in a quick glance. The essential functions of the present invention earthquake alerting apparatus include indicating the direction of the epicenter of a major earthquake, providing an auditory alert for small warning shocks and after shocks, and providing information on the exact time of the earthquake.

Abstract: A seismic sensor platform comprises an open frame and a plurality of seismic motion sensors vertically positioned in a common horizontal plane in spaced relationship around the periphery of the open frame. A spike associated with each of the sensors extends beneath the open frame for anchoring each of the sensors in the earth. The frame includes a shield for protecting the sensors from physical damage and for shielding them from seismic noise. Second and third pluralities of horizontally positioned sensors may be provided on the frame, orthogonally positioned with respect to each other to sense orthogonal components of reflected seismic waves. The sensors may each be of a different natural frequency to optimize the multifrequency output of the sensor array.

Abstract: The method of implanting a geophone in the earth including the steps of drilling a borehole in the earth, pumping grout into the borehole, pumping a geophone down the interior of a cylindrical pipe positioned in the borehole, the end of the pipe being adjacent the desired point of implantation of the geophone, and pumping additional grout into the borehole to completely surround the geophone and allow the grout to solidify. In one embodiment, a tubular drill pipe having a severable drill bit at the lower end is first used to drill a borehole, after which the drill bit is hydraulically severed from the tubular drill pipe and the grout and the geophone are pumped down into the hole through the interior of the drill pipe.

Abstract: A method and apparatus for recording acoustical and seismic signals at the ocean bottom with minimal noise. A seafloor seismic recorder couples geophones to the water bottom, stores the seismic data, and is retrievable. The device is comprised of a chassis, a ballast ring, an electronics control package, a geophone package, a buoy means, and a leg extension means. The geophone package is disconnectably connected to the portion of the control package housing, so that the geophone package can remain coupled to the seafloor, when the control package and chassis rise toward the surface for a short distance. The buoy means permits the ballast ring and geophone package to become embedded in the sediment upon impact, and allows the chassis, geophone package, and control package to rise to the surface upon release of the ballast ring.

Abstract: A seismic system is placed in a predetermined orientation with respect to a surface of a formation, and a low viscosity substance is introduced between the sensor system and the surface of the formation. The substance has a composition formulated for stiffening in situ by increasing viscosity to provide a mechanical bond and an acoustical signal transmission coupling between the sensor system and the formation. After completion of the seismic operation, the stiffened substance is contacted with a stimulus for breaking the stiffened substance and thereby break the mechanical bond. Thereafter, the sensor system is recovered.

Abstract: Apparatus for attenuating Stoneley waves propagating in a borehole along a given direction, the borehole containing a fluid in which at least one seismic transducer is immersed. According to the invention, the apparatus comprises pressure transmission means firstly for placing in a region of the borehole where the hydrostatic pressure is not less than the hydrostatic pressure at the level of the seismic transducer, and secondly for transmitting pressure to at least one flexible hose containing a gas, the hose being disposed upstream from the seismic transducer relative to the propagation direction of the Stoneley waves. The apparatus is applicable to geological exploration by performing a seismic survey in a borehole.

Abstract: A geophone system for measuring mechanical vibrations such as seismic waves include a mechanical transducer with an electronic processing circuit. The mechanical transducer includes an inertial mass adapted to be excited by an input acceleration signal and by a force transducer. The excitation is detected by a sensor element and the processing circuits of the geophones control the force transducer and are connected with a central station via a transmission line.

Abstract: A seismometer system which provides readouts of the time integral (Cumulative Absolute Velocity or CAV) of the acceleration time history of an earthquake. CAV is found to be a measure of the structural damage potential of an earthquake. Three triaxial low frequency acceleration sensors are connected into a digital computer system. Each sensor has a capacitive pickoff, whose capacitances determines the length of an electrical pulse; the pulse gates high-frequency clock cycles into a counter. The counts are summed to give the time integral. A microprocessor provides for periodic re-zeroing and other calibration functions, and for the actuation of alarms, relays and electrical pulses for utility shutoff and the like at predetermined levels of CAV. The acceleration time history of the earthquake is stored in the memory for later retrieval if desired. The whole system is contained in a small inexpensive package.

Abstract: In accordance with illustrative embodiments of the present invention as disclosed herein, a leader cable is anchored to a post on the upper end of a geophone case having a spike on its lower end that penetrates the ground to hold the case in an upright postion. The anchor is formed by a continuous stress member in the cable that is looped around the post to isolate the electrical conductors in the cable from strains imposed on the cable. The post can be an integral part of a block located at the upper end of the case, or a bobbin that is captured by a cap that closes the top of the case.

Abstract: A geophone configuration is disclosed that includes an elongated extension or spike that couples with the soil in the hole made by the spike in the region near the end of the spike without hard or firm coupling with the soil above that region. A bow spring or drill bit larger in diameter than the diameter of the spike can be used for achieving predominant contact for the coupled region compared to soil opposite the remainder of the spike. Alternately, a weighted tip can be employed to achieve relative superior coupling by weight compared with the less heavy region of the spike above such weighted tip.

Abstract: A method for high-resolution seismic recording with increased bandwidth using detectors planted at shallow depths below the earth's surface. In one embodiment, an optimum depth where the amplitudes of high frequency signals increase relative to that of the noise during high-resolution recording is determined, geophones are then planted at that optimum depth and signals are recorded at that depth. To find this optimum depth, detectors are planted at various depths below the earth's surface in order to record the signals at those various depths. The frequency spectra for each detected signal is generated and a velocity profile of the depths covered by the detectors is also generated from the signals. The bandwidth of the frequency spectra and the velocity profile are used to determine a depth for planting the detectors that is closer to the earth's surface than the depths previously considered.

Abstract: An apparatus and method of high resolution reverse vertical seismic profile (VSP) measurements is shown. By encapsulating the seismic detector and heaters in a meltable substance (such as wax), the seismic detector can be removably secured in a borehole in a manner capable of measuring high resolution signals in the 100 to 1000 hertz range and higher. The meltable substance is selected to match the overall density of the detector package with the underground formation, yet still have relatively low melting point and rigid enough to transmit vibrations to accelerometers in the seismic detector. To minimize voids in the meltable substance upon solidification, the meltable substance is selected for minimum shrinkage, yet still having the other desirable characteristics. Heaters are arranged in the meltable substance in such a manner to allow the lowermost portion of the meltable substance to cool and solidify first.

Abstract: An instrument for sensing seismic waves and determining their direction of propagation is operable at considerable depth in a borehole. It comprises a short, stubby sensor module with means to clamp it to the borehole wall and including three accelerometers, and connected by a flexible umbilical cord to a primary module suspended by a cable. The down-hole electronics and the power supply for the clamp means are provided in the primary module. The sensor module has a fundamental resonant frequency about 1 kHz, well above the frequency of the seismic waves it is subjected to, so that the signals from the accelerometers accurately represent those waves.

Abstract: In accordance with an illustrative embodiment of the present invention, a water-proof geophone housing assembly includes a lower body member housing a seismic transducer, a cap member closing the upper end of the lower body member, an upper body member molded over the cap member and an upper portion of the lower body member, there being a molecular bond between all confronting surfaces of the members to prevent entry of moisture. The electrical lead wires extending from the transducer through the cap member and upwardly out of the upper body member are water blocked to prevent migration of water therealong.

Abstract: A light weight and compact geophone assembly for detecting transient seismic signals along orthogonal axes. The geophone assembly having a plurality of geophones arranged within close proximity of each other within a compact housing. The geophones are interconnected to a conductor cable passing through the housing in a unique water-tight sealing arrangement. At the cable entrance into the housing, the conductor cable is surrounded by a tapered boot compressed about the cable by a sleeve which in turn is fixed in place by a locking nut. The locking nut is received by complementary threads at the cable entrance into the housing. When tightened, the locking nut forces the compression sleeve over the tapered surface of the boot, compressing the boot about the cable. In addition, the locking nut and compression sleeve urge the boot in compression between the cable and the housing. Located atop of the housing is a bubble leveling device.

Abstract: A transducer (700) of great sensitivity is disclosed which incorporates a magnetohydrodynamic (MHD) cell (738) exposed to the flow of a electrically conductive fluid (712) within a channel (704). Flexible diaphragms (722) form the ends of the channel (704) and deflect with the fluid motion. The deflection is sensed by strain gauges (724) and the signals from the MHD cell and strain gauges are processed. In addition, an MHD power generator is contemplated which generates power from a moving electrically conductive fluid, such as sea water in geophysical motion. A strong magnetic field is established normal the direction of fluid flow. Electrodes are positioned normal to both the magnetic field and fluid flow to complete a circuit to transfer the power generated by the movement of the electrically conductive fluid through the magnetic field.

Abstract: A seismographic sensor is constructed from a D'Arsonval movement. The elements of the movement include a coil suspended in the field of a permanent magnet and a pointer attached to the coil. A weight is attached to the pointer and acts as an inertia element. Leveling screws are provided to control the period of the weighted pointer and to control the resting position of the pointer. When the base of the meter vibrates during an earthquake, the weighted pointer does not follow the vibration because of its inertia, resulting in a relative rotation of the meter coil and the magnet field, thereby inducing a voltage in the coil. This voltage is proportional to one component of horizontal velocity of the earth's motion. Means are provided to process and record the magnitude of this voltage.

Abstract: For seismic monitoring of a petroleum deposit at least one signal receiving unit is fixed to an outside of a casing pipe before the casing plate is cemented in a borehole passing through the monitored zone.At least one housing, defined by projecting elements, (longitudinal members, stops), is provided along an outer surface of the casing pipe, with the where the reception unit being embedded and fixed therein so as to protect the reception unit from shocks or compressive forces which may occur during lowering of the pipe into the well. Each reception unit comprises a support assembly with cavities for sensors, electronic cards for amplifying the signals delivered by the sensors and a sealed external case which is easy to position and which is held firmly in position by embedment in the housing. A multiconductor cable is used, for example, for connecting the reception unit to the surface.

Abstract: A method of measuring the shear modulus profile of a seabed floor using one or more bottom shear modulus profilers, each having a seisometer package to measure the seabed motion in three dimensions and a sensor for measuring the pressure at the seabed floor, placed on or below the seabed floor, and a means for converting the measurements derived therefrom into a shear modulus profile.

Abstract: An echographic technique based method for prospecting of the subsoil or sea bottom and the like, by means of acoustic waves and carried out by the use of an apparatus constitued, in combination of a known acoustic wave transmitting equipment (1) comprising of a body (6, 8) in the inside of which a chamber (9) is formed defined by an internal reflecting surface (7) shaped like a round paraboloid of axis (Y--Y), closed at the base by an elastic diaphragm (5) and filled with a proper liquid, into which acoustic waves are emitted produced by a pair of main electrodes (10a, 10b) associated with an auxiliary discharge priming electrode (11) put between the first ones.

Abstract: An accelerometer for blast monitoring comprises at least one piezoelectric transducer having a piezoelectric membrane attached along the edge thereof to the sidewall of a suitable container and mounted for free movement in such container for generating a high impedance electrical output signal upon deformation of the piezoelectric membrance by vibration during a blast, a high to low impedance converter connected to the piezoelectric membrane for converting the high output impedance of the piezoelectric membrane into a low impedance signal for transmission through long cables to recording equipment, and means for encapsulating the piezoelectric transducer and converter into epoxy or other solid material to minimize response of the transducer to surrounding acoustic signals.

Abstract: The invention describes a method and apparatus for the acoustic signalling of cases of drowning in swimming pools, to guarantee reliable trigger of the alarm while avoiding any false alarms. This is effected basically by a switching element (1) in a water-tight encapsulation, which is disposed beneath the surface of the water and which, in the event of an alarm, triggers a first alarm device (2) and delivers an acoustic signal via a signal horn (5). A transmitter (6) is also connected to the alarm device (2) and transmits the alarm signal to a receiver at a distance and to another alarm device (10). Instead of the switching element (1), a microphone (12) can advantageously be used for cases in which the swimming pool water is frozen.

Abstract: In an acoustic ground vibration detector for the detection of infrasound ground vibrations, comprising at least one three-component geophone probe, the three individual geophones of said geophone probe are electrically connected in series and act upon an operation amplifier whose output signal activates a Reed relay. The activated Reed relay switches on a sound signal transmitter which produces an audible acoustic signal for the duration of the ground vibration signal. The acoustic ground vibration detector is intended in particular for locating buried persons. Moreover, it serves to protect important objects by registering infrasound ground vibrations produced by footfall sound.

Abstract: A geophone designed to measure the vibrations of bodies, especially vibrations in the earth's crust, comprises two-strip sensors made of piezoelectric polymer, embedded by one end in the geophone casing and resting freely, by one side, on the inertial mass of the geophone, thus enabling the making of geophones with a very wide pass-band.

Abstract: An apparatus for implanting and positioning a geophone assembly into the earth is disclosed. The geophone implanting apparatus includes a receptacle for receiving and retaining a geophone assembly. A magnetic compass and a cylindrical bubble level are mounted concentrically approximately one meter from the receptacle so that the ferromagnetic properties of the geophone do not induce errors in the azimuth measurement. A pair of radially disposed handles are utilized to rotationally manipulate the geophone into a proper orientation during implantation. After the geophone assembly has been implanted and leveled a release mechanism is utilized to release the geophone from the receptacle by deforming a spring grip mechanism which is utilized to retain the geophone. In the depicted embodiment, a geophone assembly having a radially non-symmetric case is utilized in conjunction with a matching receptacle so that a unique orientation of the geophone may be accomplished.

Abstract: A seismic detector assembly is disclosed that includes a housing and a seismic detector or geophone located in the housing. The geophone has a pair of external terminals that are positioned asymmetrical to the longitudinal axis of the geophone. A printed circuit board having conductive strips for connecting the terminals to leader cables is located in the housing above the geophone. The printed circuit board has a pair of asymmetrical openings through which the asymmetrical terminals can extend only when the printed circuit board is oriented in one position relative to the geophone. Marks on the printed circuit board indicate which conductive strip should be connected to which terminal and the proper orientation of the printed circuit board relative to the truck that receives the output of the geophone.

Abstract: A sensor for resolving the left-right ambiguity encountered in horizontal line hydrophone arrays consists of an orthogonal pair of dipole hydrophones, a monopole hydrophone, and a tilt sensor, the tilt sensor connecting the dipole hydrophones so as to provide a single dipole hydrophone which is always oriented horizontally. The tilt sensor consists of two variable capacitors made from hollow cylinders of high permittivity dielectric material, partially filled with a quantity of liquid mercury which forms the variable inner electrodes of the capacitors. The outer electrodes of the capacitors, on the outside of the cylinders, having a sinusoidally-shaped perimeter and being oriented at right angles to each other, are connected to the crossed dipoles in order to provide the required horizontal dipole hydrophone.

Abstract: An apparatus for supplying the power requirements of an Ocean Bottom Seismometer is disclosed wherein the power supply is separate from the power consuming devices of an Ocean Bottom Seismometer and mounted on the weight holding the Ocean Bottom Seismometer on the ocean floor during recording.