STUDY OF THE ACOUSTICAL EFFECTS OF SUB-BOTTOM ABSORPTION PROFILES

This paper considers the acoustical effects of variations of sediment absorption with depth for several sediment types. A simple measure of absorption effects is given by the total absorption along the sub-bottom ray paths. This total absorption is considered for a variety of absorption and sound-speed gradients for both semi-infinite and finite layers. The plane wave reflection loss (bottom loss) is then considered for several treatments of attenuation, layering, and sediment type. It is found that, for clay sediments, plausible variations in absorption gradients can result in variations in bottom loss of several decibels. These conclusions are reinforced by consideration of the absorption gradient effects on normal mode attenuation coefficients. © 1979, American Institute of Physics. All rights reserved.