Backscattering of Explosive Sound from the Deep‐Sea Bed

The return by the deep ocean bottom of the sound produced by an explosive charge consists of a decaying burst representing scattering at successively decreasing grazing angles with the bottom. An analysis of shot records at three deep‐water locations between Cape Hatteras and Bermuda has yielded the backscattering strength of the sea bottom over a range of frequencies and angles between 30° and 90°. In the range 30° to about 65° the bottom appears to behave as a diffuse backscatterer of sound; between 65° and 90° (normal incidence) an increased return may represent reflection from inclined flat facets of the sea bed or from sub‐bottom sediment layers. Analyses in several frequency bands between 0.5 and 8.0 kc indicate no frequency dependence of the scattering strength that could not be due to shock‐wave attenuation effects in the sea. The coefficients agree with those obtained with pulsed sinusoidal sound sources.