This create under the surface of a sheet of water, a shock wave from a plurality of seismic sources for imploding, and apparatus for implementing it.

摘要

In order to improve the spectral purity of the seismic signal, a number of individual sources are triggered by synchronising all of them using their implosion peak PI1 - PI4 and by choosing sources having different bubble periods Tb1 - Tb4 so that the times at which the explosion peaks PE1 - PE4 appear are shifted and spread out over time. The resultant signal has a residual explosion peak PE' which is highly attenuated in comparison with the resultant implosion peak PI'. The different bubble periods can be achieved by using multiple-muzzle guns fired simultaneously, since the bubble period decreases as the number of muzzles increases. IMAGE