Abstract: Sea-Floor Acoustic Backscatter on the Mississippi-Alabama Outer Continental Shelf

J. Scott Laswell, William W. Schroeder, William W. Sager

Side-scan sonograms of the sea-floor and subbottom reflection profiles of the upper sediment layers were collected during a high-resolution geophysical study of the Mississippi-Alabama outer continental shelf. Sonar data reveal two categories of acoustic backscatter patterns: (1) homogeneous, and (2) patchy. Homogeneous backscatter appears uniform on the sonar records, and was divided into four arbitrary levels based on the strength of acoustic return. Six patchy backscatter patterns were identified, ranging from amorphous "splotches" to more regular lineations. Although much of the high homogeneous backscatter is found associated with topographic features, such as sand ridges and calcareous mounds, most areas of patchy backscatter occur independent of topographic relief. The various atterns of acoustic backscatter observed during this study are likely a function of both the differences in the degree of sea-floor roughness, and the changes in the type of sediment found both on and beneath the sea floor.

AAPG Search and Discovery Article #90983©1994 GCAGS and Gulf Coast SEPM 44th Annual Meeting, Austin, Texas, October 6-7, 1994