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

5pUW7. Inversion of normal incidence backscatter data from gassy sediments.

Timothy J. Kulbago

Kenneth E. Gilbert

Appl. Res. Lab. and the Graduate Program in Acoust., Penn State Univ., P.O. Box 30, State College, PA 16804

Simulation studies of normal-incidence backscatter from shallow-water sediments indicate that high-frequency probe signals (f(approximately equal to)30 kHz) cannot easily distinguish between soft gassy sediments and hard nongassy sediments. Much lower frequencies, on the other hand, clearly differentiate between the two cases. An approach is presented here that uses gross structural information from high-frequency probe signals together with inversion of low-frequency data to extract the physical properties of the near-surface sediment. The approach is applied to simulated backscatter data for both gassy and nongassy sediments. Possible experimental tests of the method are described.