Abstract: Two modifications of an offshore marine seismic energy source tow system are disclosed. Both systems comprise transmitters and receivers therein for continuously measuring the distance between a vessel towed submerged geophone streamer cable and a towed seismic air gun supporting paravane on each side of the streamer cable for generating and transmitting corrective steering signals to the paravane for maintaining each seismic air gun spaced from the towed submerged geophones at an exact predetermined distance for producing more accurate seismic velocity measurements. One embodiment has the acoustic transmitter on the geophone streamer cable and an acoustic receiver on each paravane in line with the transmitter, and a second embodiment has an acoustic transmitter on each paravane and a corresponding acoustic receiver for each paravane on the geophone streamer cable transversely of the transmitter. Methods for assembling the above two systems are disclosed.

Abstract: Methods for maintaining a steerable paravane supported seismic energy source, as an air gun, positioned laterally at a precise constant predetermined distance from a geophone mounted on a submerged geophone streamer cable while recording offshore marine seismic reflection data from a seismic tow system including electrical controls on a recording boat for towing the paravane and geophone streamer cable. Two modifications are disclosed.

Abstract: In seismic delineation of sedimentary section below the surface of a seismic energy propagation medium, a new use for an old article is disclosed. It includes a basic method for generating and shaping a seismic energy pulse comprising (1) generating a first energy pulse downwardly through the shortest distance to a point at the lower end of a vertical straight explosive material for forming a compressional forward portion of the seismic energy pulse, and (2) generating a second energy pulse later to form a rarefactional aft portion of the seismic energy pulse. By varying the length of the explosive material the lengths of the forward and aft portions are varied for controlling the shape of the seismic energy pulse, and by varying the position of the point of ignition of the linear explosive material, additional shaping of the seismic energy pulse results.