Abstract: A geophone and a geophone planting tool adapted to engage the outer case of the geophone, to hold it securely during aligning, leveling and implanting into the earth and to release it upon lifting the geophone planting tool from the geophone have matable surfaces which enable forces to be transmitted from the geophone planting tool to the geophone.

Abstract: A geophone apparatus capable of detecting both horizontal shear and compressional seismic waves has a pair of geophones mounted such that, when in use, said geophones will be inclined at an angle of about 45.degree. in opposite directions from vertical. The output signals generated by the two geophones are summed to yield a compressional wave trace and/or are subtracted one from the other to yield a horizontal shear wave trace.

Abstract: The invention is an apparatus for obtaining a step function response signal from a geophone, comprising: (1) a controllable source of current; (2) a means for producing a switching pulse; (3) an electronic connecting means for applying current from the source to the geophone, while the pulse is being produced; and (4) an electronic connecting means for conducting the response signal from the geophone to a data acquisition system, after the pulse has been produced. Preferably, a time delay means is used to delay the connecting of the signal to the data acquisition system, for a time after the pulse has been produced.

Abstract: A rotating eccentric weight apparatus and method for generating coded shear wave signals for use in seismic exploration. The apparatus includes a rotatable eccentric and a position sensor capable of detecting each instant that the eccentric passes a particular angular position about its axis of rotation and generating a code signal for use in correlating the raw seismic data obtained. In one embodiment, the apparatus includes an outrigger shovel which transmits a sinusoidal shear wave signal generated by the rotating eccentric while the rest of the apparatus is caused to alternately decouple from and impact against the earth surface to transmit a coded train of pressure wave impulses into the earth.

Abstract: A rotating eccentric weight apparatus and method for generating coded shear wave signals for use in seismic exploration. The apparatus includes a rotatable eccentric and a position sensor capable of detecting each instant that the eccentric passes a particular angular position about its axis of rotation and generating a code signal for use in correlating the raw seismic data obtained. In one embodiment, the apparatus includes an outrigger shovel which transmits a sinusoidal shear wave signal generated by the rotating eccentric while the rest of the apparatus is caused to alternately decouple from and impact against the earth surface to transmit a coded train of pressure wave impulses into the earth.

Abstract: A seismic exploration method in which a rotating eccentric weight seismic source is employed to transmit a coded energy signal into the earth. A position sensor mounted on the source directly detects the instants at which the rotating eccentric passes a particular angular position about its axis of rotation, and generates a code signal which is used to correlate the raw seismic data. Preferably the source is allowed to decouple from the earth surface such that the coded energy signal transmitted into the earth is a coded impulse train.

Abstract: Compact, lightweight, rotating eccentric weight seismic sources and a seismic exploration method particularly suitable for use in relatively inaccessible onshore regions. The source includes an eccentric weight rotatable about an axis and a sensor to detect the instant of peak earthward force developed by the source. A coded energy signal is transmitted into the earth and the seismic waves returned from within the earth are detected. The polarity of a signal proportional to the seismic waves is periodically sampled to produce a plurality of sign-bit samples. The sign-bit samples are automatically shift-summed in response to a code signal generated by the sensor, thereby forming a plurality of shift-summed samples which are recorded to provide a correlated seismic trace.