A note on attenuation and dispersion in marine sediments

Propagation loss is a critical factor for sonar performance.Low-frequency sound propagation loss is largely determined by acoustic attenuation in the sea bottom. This memorandum is part of an ongoing project where the objective is to quantify the bottom loss in areas of operational interest, and to provide appropriate methods for acquisition of relevant bottom data. To achieve this objective it is essential to understand how sound interacts with sediments of different characteristics. This memorandum summarizes and discusses theoretical models of physical mechanisms that govern acoustic propagation in marine sediments, in particular the frequency dependence of attenuation ' and sound speed (i.e. dispersion).