Abstract: A method is described for controlling the magnetic field strength of an electromagnetic geophone by: a) providing a specified center value each for a geophone sensitivity parameter and a geophone damping parameter; b) magnetizing an electromagnetic geophone to full saturation of the magnet; c) measuring the value each for the fully saturated geophone sensitivity parameter and damping parameter; d) partially demagnetizing the geophone; e) measuring the value each for the partially demagnetized geophone sensitivity and damping parameters; f) calculating a slope for a geophone demagnetization line representing geophone demagnetization versus demagnetizing force by utilizing the measured fully saturated geophone sensitivity and damping parameters as one point on the line and utilizing the measured partially demagnetized geophone sensitivity parameter and damping parameter as another point on the line; and g) calculating an amount of demagnetization required to provide the geophone with sensitivity and damping par

Abstract: A method and apparatus of making a splice in a geophone cable for providing a weatherproof cable splice with maximum cable break strength. The ends of each of the cables are soldered to a printed circuit board to provided the necessary cable strength. The printed circuit board is covered by a silicone rubber boot which sealingly engages the ends of each of the cables on either side of the printed circuit board to insure moisture protection.

Abstract: The method of detecting vibrations comprises establishing a magnetic circuit with magnetic flux producing means and at least one airgap. Elastically supporting an annular non-magnetic conductor within the airgap. Fixedly supporting an annular coil in the airgap without there being relative movement between the coil means and the airgap, so that an electric signal becomes induced in the coil means in response to relative movement between the annular conductor and the airgap.The vibration transducer comprises a magnetic circuit having magnetic flux producing means and at least one airgap. An annular non-magnetic conductor is elastically supported within the airgap. An annular coil means is fixedly supported in the airgap without there being relative movement between the coil means and the airgap, so that an electric signal becomes induced in the coil means in response to relative movement between the annular conductor and the airgap.

Abstract: The seismic method comprises in one preferred embodiment, towing a long, flexible member over the earth's surface, the member having liquid-filled geophones mounted thereon or coupled thereto and suitably spaced therealong, and a seismic cable for receiving the individual outputs of the geophones. Each liquid-filled geophone provides an output electric signal having a polarity corresponding to the direction of the earth's motion. In another embodiment of the method of this invention, the geophones are positioned on the earth's surface in a predetermined pattern; their output signals are transmitted to a utilization device; then the geophones are moved to another location, and the detection process is repeated.In a simplified embodiment, the geophone comprises a hollow cylindrical casing defining a chamber therein. A high-density liquid substantially fills the chamber. The chamber has a flexible bottom wall which constitutes a force or pressure transducer.

Abstract: A multi-purpose seismic transducer includes a first seismic sensor having a first transfer function. A transfer-function shaping filter is coupled to the output of the first seismic sensor. The filter is adjustable to shape the first transfer function to match a plurality of different second transfer functions.

Abstract: The electric multi-contact connector consists of twin half-housings. Each half-housing carries a plurality of contact holders independently mounted in spaced-apart relationship on a multi-bore base. The prong-end of each contact is resiliently supported by its holder and makes a water-tight joint therewith. When the two half-housings are moved into latching engagement, each pair of mating prong-ends of the opposite connector half-housings inosculate. Each prong-end is preferably serrated to improve the conductivity between each mating pair of prong-ends under adverse operating conditions.

Abstract: Seismic waves are detected for a given seismic prospect with an accelerometer and a hydrophone and the outputs of said accelerometer and hydrophone are combined directly to create a signal for seismic analysis. The accelerometer and hydrophone may be combined physically in a single composite unit for recording the seismic waves or an accelerometer and hydrophone may record the seismic survey independently for subsequent combining of the signals from the accelerometer and hydrophone.

Abstract: A conventional electromagnetic geophone includes a coil assembly that is spring-suspended in an air gap between concentric pole pieces of a magnet. The coil assembly is wound on the outer wall of a bobbin. The bobbin is typically made from or includes a metallic material to provide a mass for mechanical damping and a conductor for electrical eddy-current damping of the spring-suspended coil assembly. The improvement of this invention lies in mounting on the bobbin, a vernier mechanical damping mass made of a coil of insulated wire. The coil is open-ended and the mechanical damping force is adjustable in accordance with the number of turns in the coil.

Abstract: The seismic transducer comprises a hollow, elongated casing having a bore defining a chamber. An opening extends through the wall of the casing into the chamber. A hydrophone is removably disposed inside the chamber. The hydrophone comprises an elastomer body in a portion of which is embedded a rigid cage marginally supporting a pressure detector assembly. Means are coupled to the casing for exerting a static pressure on the elastomer body. The cage has a geometric configuration adapted to substantially shield the detector from the static pressure which causes the end portions of the elastomer body to expand outwardly, whereby each end portion forms a fluid-tight seal against the wall of the chamber.

Abstract: The marine connector comprises a pair of complementary connector units, each attachable to an electric cable-end for interconnecting the same. Each connector unit has longitudinally-spaced, front and rear end walls interconnected by an axial transverse partition. Male and female electric contact elements are mounted on the front wall of each connector unit on opposite sides of the partition and are aligned for telescopic connection with one another. The conductor ends are anchored to the partition by means including a solder ball and extend therefrom to the related contact elements. A sealing sleeve made of a flexible resilient material is slidably mounted on the cable-end portion leading to each unit.

Abstract: The transducer unit includes a rigid hollow casing. The casing defines through its cylindrical wall a plurality of sound-transmitting windows. A hydrophone having an elastomer core is removably positioned in the bore of the casing opposite to the windows. A pressure transducer element is embedded inside the core. The core is slightly compressed so as to form plugs for the windows.

Abstract: A geophone case with an improved internal cable anchor. The anchor has three parallel bores extending in a longitudinal direction for tightly accepting a cable therethrough, whereby the cable makes two 180.degree. bends which provide the necessary reaction force to the cable.