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

1pUW12. Analyses of DTAGS acoustic array reverberation data from exposed rocks and sediment covered areas of ARSRP fine-scale experiment.

Ashok K. Kalra

James K. Fulford

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

Acoustic reverberation data that were acquired with Naval Research Laboratory's (NRL's) Deep Towed Acoustic/Geophysics System (DTAGS) over exposed rocks and sediment covered areas for the Acoustic Reverberation Special Research Program's (ARSRP's) fine-scale experiment were analyzed. DTAGS is identical to a seismic streamer with its own energy source but has two collinear receiver arrays (acoustic and geophysics) and the whole system can be towed to 5000-m depths close to the sea bottom. Only acoustic array data were analyzed to study the reverberation phenomena in the area. DTAGS acoustic array data were acquired with a point source LFM signal ranging from 250 to 650 Hz of 125-ms duration. The data were deconvolved for source signal recorded in the field and beamformed in time domain in order to preserve the higher frequencies of the returned signal. The beamformed data to isolate the reverberation signals pertaining to specific insonification areas of exposed rocks and/or sediment covered areas were analyzed. The reverberation from exposed rocks and sediment covered areas were analyzed for their frequency content and grazing angles to determine their relationships with scattering strengths. [Work sponsored by the Office of Naval Research.]