ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

4aUW9. Seismoacoustic modeling of thin sedimented regions in the mid-Atlantic ridge.

Stanley A. Chin-Bing

Naval Res. Lab., Stennis Space Center, MS 39529-5004

Joseph E. Murphy

Univ. of New Orleans, New Orleans, LA 70148

In several previous meetings results have been reported comparing computer generated acoustic simulations with reverberation data taken from the mid-Atlantic ridge region during the 1993 Acoustics Experiment (``Site A, Seg 076'' from the ONR Acoustic Reverberation Special Research Program). The acoustic simulations used representations of the rough, range-dependent ocean sediment/subbottom bathymetry that were generated by geomorphology models (the Webb--Jordan sediment distribution model and the Goff--Jordan fractal seafloor/basement model). A modified version of the Collins FEPE2WAY model was used for the long-range reverberation predictions. The simulated backscatter signal (210--280 Hz) compared favorably, in structure and level, with the reverberation data. In this study the same PE model is used to propagate the incident field to a thin sedimented region of interest. This field is then used as the initial field to the FFRAME and SAFE models to study the seismoacoustic influence of the thin sedimented regions on reverberation. Results will be presented that indicate the effects that shear waves and shear wave attenuations have on the reverberation. [Work supported by Office of Naval Research, Acoustic Reverberation SRP, and a High Performance Computing DoD Shared Resource Center grant.]