Backscatter from gas bubbles in muddy sediments

Recent experimental evidence suggests that trapped gas bubbles may be dominant in backscatter from sandy sediments. A model based on scattering from a spatial distribution of resonant bubbles was previously used to predict shallow grazing angle backscatter from sandy sediments [F. A. Boyle and N. P. Chotiros, J. Acoust. Soc. Am. 93, 2397 (1993)]. A similar model is developed for predicting backscatter from muddy sites. The sediment gas fraction is treated as a free parameter in fitting model predictions to measured backscattering strengths. Model predictions are compared with experiment. [Work supported by NRL/SSC.]