Theoretical and experimental investigations of the seismic effects of underwater explosions of dynamite charges are described. We investigate the acoustic efficiency in a broad frequency band and in the seismic frequency band, the partition of energy between the shock wave and bubble pulses, the seismic effects of cavitation due to ghost reflection at the air‐water interface, and the damage caused to marine life. Results concerning the variation of the seismic efficiency with shot conditions are given: the conclusion is that the seismic efficiency of charges of the order of 100 gm can be considerably increased by dividing the charges and by shooting at depth. Experiments show that two or three properly spaced 50 gm charges of dynamite, shot at a depth of about 12 m, give the same result as a single charge of about 5 to 15 kg shot at a depth of 1 m. CDP marine sections comparing caged charge shooting with conventional shooting in the same area are shown.
Surface waves generated by underwater explosions offshore Scotland