### ASA 126th Meeting Denver 1993 October 4-8

## 2pUW8. Two-dimensional modeling of low-angle backscatter from geologically
realistic seafloors.

**R. A. Stephen
S. A. Swift
**

**
**
*Dept. of Geol. and Geophys., Woods Hole Oceanogr. Inst., Woods Hole, MA
02543
*

*
*
The numerical scattering chamber has been used to quantitatively predict
low-angle backscatter coefficients for a suite of seafloor models. A number of
issues have been addressed: (a) How finely does seafloor bathymetry need to be
resolved in order to predict the backscattered field? Corollary issues in this
area are (i) at what resolution can one go from a deterministic to a stochastic
representation and (ii) how should one interpolate between bathymetric data
points? (b) How important are shear (rigidity) properties of the sediment and
basement in a predictive model of seafloor backscatter? (c) How important is
intrinsic attenuation (anelasticity) in a predictive model of seafloor
backscatter? (d) How do the magnitude and mechanisms of backscatter vary with
increasing sediment cover? (e) How effective are isolated facets on the
seafloor in generating strong backscatter? (f) Can realistic volume
heterogeneities within the sediment and basement generate comparable
backscatter levels to realistic seafloor roughness? These issues will be
discussed by comparing backscatter coefficients for various seafloor
representations.