A broadband model for a range of ocean sediments

Abstract

In the context of the Biot theory of sound propagation in porous media, particularly water-saturated granular media, Yamamoto and Turgut [J. Acoust. Soc. Am. 83(5), 1744–1751, May, 1988] have shown that the pore size distribution can have a profound effect on the frequency dependence of the attenuation of sound. In sandy sediments below the characteristic frequency, the attenuation is predicted to increase as the second power of frequency. In soft sediments, it is found that the rate of increase is closer to the first power. By adjusting the width of the pore size distribution, it is possible to smoothly change from the second power of frequency to the first power, in certain frequency bands. This suggests that pore size distribution may be a critical parameter in the determination of sound attenuation in the seabed. The model predictions are compared to measurements from the Shallow Water 2006 experiment as an illustration. [Work supported by the Office of Naval Research, Ocean Acoustics Program.]