## 2pUW11. Angular variation in the simulated reflection and scattering properties of granular poroelastic ocean sediments.

### Session: Tuesday Afternoon, May 14

### Time: 4:05

**Author: Dennis J. Yelton**

**Author: Nicholas P. Chotiros**

**Location: Appl. Res. Labs., Univ. of Texas, Austin, TX 78713-8029**

**Abstract:**

Reflection and scattering properties of an inhomogeneous poroelastic medium
were studied via numerical simulation. The inhomogeneous medium was modeled as
an ensemble average of randomly layered poroelastic material. Each layer
represented a granular material of a particular grainsize. The thickness of each
layer was related to the associated grainsize and porosity by a conservation of
mass relationship. Lateral variations in grainsize were approximated by
performing a coherent ensemble average of results from several realizations of
the randomly stratified medium. Poroelastic medium parameters were chosen to
represent water-saturated sand. The mean and standard deviation of the grainsize
distribution were chosen to match existing experimental data in order to test
the model. Specifically, the inhomogeneous medium was modeled as bounded by a
homogeneous water half-space on the source side, and a homogeneous poroelastic
half-space of equivalent average porosity on the other side. Reflected signals
were computed for high-frequency plane waves incident at various grazing angles.
Coherent and random components of the reflected signal were calculated. The
coherent part was related to the reflection coefficient. The random component
was related to the scattering strength of the medium. Results were compared with
existing experimental data. [Work supported by ONR.]

from ASA 131st Meeting, Indianapolis, May 1996