Computer Model Predictions of Ocean Basin Reverberation for Large Underwater Explosions

Abstract

Ocean basin reverberation results from interaction of the pressure wave from a large underwater explosion with the boundaries of the basin and of the seamounts and islands within it. Its net effect is to raise the ambient noise level at low frequencies for periods of from 30 minutes to 3 or 4 hours, depending on the acoustic source level and the size of the ocean basin.

A computer model has been developed to predict the reverberant field. This model has adequately matched experimental data for varying conditions in the North Atlantic, for explosive yields of up to ten tons. As an important test of its validity, we have applied the model for three high explosive shots, O.5 to 1 kiloton in yield, one in the Atlantic and two in the North Pacific, a basin with much greater area and myriad seamounts and islands. The remarkably good agreement between model results and data indicates that the assumptions made in developing the reverberation model are valid not only in the Atlantic, but can be applied equally well to making predictions of the character of the reverberant field for much larger sources in the much more complex Pacific Ocean environment.