ASA 127th Meeting M.I.T. 1994 June 6-10

3aAO13. Sound scattering by rough interfaces and volume inhomogeneities of a layered seabed.

A. N. Ivakin

N. N. Andreev Acoust. Inst., 4 Shvernik St., 117036 Moscow, Russia

A geoacoustic model of sound scattering by the sea floor is developed, in which the floor is considered to be an irregular layered medium with random scatterers of two types: The roughness of seabed interfaces and the volume inhomogeneities (spatial fluctuations of the acoustical parameters). Appropriate software has been developed to calculate frequency-angular dependencies of scattering coefficient on the frequency and directions of incident and scattered waves for the bottom model consisting of an arbitrary number of irregular layers. It is shown that characteristic scales of displayed interference patterns essentially depend on parameters of layers, roughness of interfaces, and volume inhomogeneities. An example of remote acoustic characterization of seabed media and estimation of their irregularities from acoustic sensing data is presented using analysis of interference pattern of the frequency-angular dependencies of backscattering coefficient of a bottom consisting of a silty layer overlaying a sandy half-space.\v