| 摘要 |
Seismic energy wave-shape control apparatus and method in which the waveshape of the acoustical waves generated in the water by the use of submerged airgun seismic sources can be controlled and selected by the survey crew to provide the waveshape which is most desirable for use under the conditions being encountered as the survey is being carried out. The pressurized gas holding charge container is provided with a plurality of chambers such that an initial abrupt flow of pressurized gas as shown at 50 in FIG. 2 occurs from a primary chamber and passes out through the discharge ports into the surrounding water with explosive-like abruptness. Delayed after-flow of pressurized gas as shown at 52 in FIG. 2 then occurs from a secondary chamber for reducing the relative magnitude and changing the waveform of the second pressure peak P2. The relative volumes of the primary and secondary chambers are conveniently changeable by detaching the casing and shifting the position of a removable barrier, thus obtaining differing waveshapes as seen by comparing FIGS. 6; 7, and 8 with FIG. 5. If desired a tertiary chamber may be utilized to provide further changes in the waveshape.
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