Abstract: This invention relates to an improved method of seismograph exploration by means of time-variant oscillatory signals whereby the side lobes of the correlograms (or of the output waveforms) are randomized to prevent constructive reinforcement during vertical or horizontal stacking. The randomization is effected by using an approximate or inexact method of correlation or convolution or by admixing random (or white) noise into the correlation process.

Abstract: A depth controller whose streamlined body has only negative variable lift-producing means, such as a pair of vanes that can produce a controllable downward force. Embodied in the controller are also means providing an uncontrollable upward force. The vanes are preferably movable by translation or rotation in a single plane, inclined relative to the horizontal. Depth control means are operatively coupled to retract the vanes inward as the controller moves from the water surface down to a reference depth. The uncontrollable positive lift producing means return the controller to the desired depth should it fall below the reference depth. Each controller can be used to effectively maintain a seismic streamer cable section at or near the desired reference depth.

Abstract: A spar buoy is dynamically stabilized by providing a streamlined, V-shaped wing just above the center of gravity of the spar. The wing has a dihedral sufficient to stabilize the spar in three axes while under tow. The buoy may be equipped with a radio transmitter and a flasher beacon for tracking by an automatic direction finder.

Abstract: This invention relates to a land seismic exploration method and apparatus employing a plurality of elongated tubes each having a flexible wall for containing a volume of liquid explosive therein. Each tube is adapted to be detachably connected to either a detonating device for exploding the liquid explosive therein thereby creating a seismic explosion, or to a pressure transducer for monitoring the pressure changes in the liquid explosive caused by the detected seismic pressure waves.

Abstract: A depth controller having a streamlined body which comprises retractable and extendable lift producing means, such as a main pair of vanes that can produce a variable negative lift and an auxiliary pair of vanes that can produce a variable positive lift. Each pair is movable by translation or rotation in a single plane, inclined relative to the horizontal. Depth control means are operatively coupled to retract the main pair of vanes inward as the controller moves from the water surface down to a reference depth and to extend the auxiliary pair of vanes outward as the controller falls below the reference depth. Each controller can be used to effectively maintain a seismic streamer cable section at or near the desired reference depth.