## 2pUW12. High-frequency bistatic scattering from elastic seafloors.

### Session: Tuesday Afternoon, May 14

### Time: 4:20

**Author: Anatoliy N. Ivakin**

**Location: Andreev Acoust. Inst., Shvernika 4, Moscow 117036, Russia**

**Author: Darrell R. Jackson**

**Location: Univ. of Washington, Seattle, WA 98105**

**Abstract:**

A high-frequency model of bistatic sound scattering is considered assuming
an elastic seabed with spatially fluctuating bulk parameters and a slightly
rough surface. The first-order perturbation solution is used to obtain an
approximate expression for the bistatic scattering strength, different geometric
configurations are considered, and the dependence of bistatic scattering
strength upon the incident and scattered grazing angles, as well as the
``bistatic,'' or azimuthal angle, is computed for various seabed types. The
parameters of the model include mean values for bulk properties and parameters
defining the spectra of fluctuations in bulk properties and seabed relief. The
influence of shear elasticity is examined by comparison with the case of a fluid
seabed having the same density and compressional wave speed. It is shown that
shear effects on both roughness and volume components of scattering are small
for sands which consequently can be treated as acoustic fluids for realistic
shear velocities (approximately 300 m/s and less). For consolidated sediments
and rock, shear effects are dominant, complicated, and very sensitive to bottom
parameters. Volume scattering exhibits a strong dependence on correlations
between the parameter fluctuations as well as their spectral aspect ratio. [Work
supported by ONR.]

from ASA 131st Meeting, Indianapolis, May 1996