The determination of acoustic source levels for shallow underwater explosions

Pressure–time records from the underwater detonation of 8‐, 48‐, and 1000‐lb explosive charges are presented. These data allow a limited verification of the extrapolation of depth dependent parametric relationships for the pressure–time waveform from deep to shallower sources. Time–domain deconvolution of the data to remove the effects of surface reflection is demonstrated. Similar methods are effective for the pressure histories in which cavitation is present or absent. The accuracy of the method is dependent on the signal‐to‐noise ratio in the data and on the relative arrival time of the surface reflected shock wave. Previously reported source energy levels have been scaled to the conditions of this data set. These scaled values generally agree with the mean energy levels derived from the data for each combination of charge weight and depth to within 1 to 2 dB.