Abstract: This invention concerns a device for emitting mechanical waves in an external medium.This device comprises an annular or axial combustion chamber, shut by a valve, and comprising means of introducing fuel and oxidant, and an ignition system; the valve is composed of a differential piston, one side of which forms a mobile wall of a chamber containing fluid under pressure, and part of the other side of which forms a mobile wall of the combustion chamber.This device is used mainly to generate compression waves for the purpose of seismic exploration.

Abstract: Seismic waves are generated by detonating an explosive gas mixture in an earth cavity formed by driving a short earth auger to a desired depth, leaving most of the augered earth in the hole surrounding the auger shaft, and then pulling the auger and shaft upwardly to lift and compress the augered earth and pack it around the auger shaft, thereby forming and sealing the cavity below the auger. The gas mixture is then introduced through the hollow auger shaft and detonated, preferably by ignition propagation through the connecting hose and the auger shaft. Upon completion of as many gas fills and detonations as may be desired, the auger is reversed and withdrawn, leaving the ground surface virtually undisturbed.

Abstract: An apparatus for generating seismic waves includes an elongated closed tube with a piston in its internal cavity. The piston is carried by a piston rod which extends through the top of the tube, and includes a fuel inlet and exhaust channel. The piston also carries a second tube to define a combustion chamber therein, and a fuel conducting tube extending along the length of the piston rod and beyond the piston to approximately medially within the second tube. When a combustion fuel is introduced to within the combustion chamber and ignited, a force is applied to the piston in one direction and an opposite force is applied to the tube moving the tube with respect to the piston a distance approximately three times the diameter of the piston.

Abstract: An apparatus and method for controlling the travel of a vehicle mounted seismic gas exploder adapted to deliver a downwardly directed pulse to the earth and thereafter be driven in an upward direction by the resultant reaction force. The exploder is flexibly coupled by means of a rope and pulley arrangement to the piston rod of a hydraulic cylinder. Compressed coil spring means aligned with the cylinder are released when the exploder jumps upward and apply a force to extend the piston rod and in so doing cause the rope to be retracted with gradually diminishing force. The exploder may be held at the upper limit of its travel, and its subsequent descent is utilized to recompress the spring means.

Abstract: A seismic gas exploder is coupled to the movable piston of a hydraulic catching system so that the piston is constrained to move with the exploder as it rebounds upward from a shot and then falls back to earth. The weight of the gas exploder is applied through the piston to increase the pressure of the hydraulic fluid in the system when the exploder is moving in a downward direction. A two-position diaphragm actuated pressure switch monitors the fluid pressure, the position of the switch contacts being effective to control an exploder firing circuit or provide other indication of the exploder's position.