Seafloor sub-bottom Imaging along the TREX reverberation track

• Published in: The Journal of the Acoustical Society of America 2014-10, Vol.136 (4_Supplement), p.2268-2268
• Main Authors: Lopes, Joseph L., Arrieta, Rodolf, Paustian, Iris, Pineda, Nick, Williams, Kevin
• Format: Article
• Language: English
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.4900195

The Buried Object Scanning Sonar (BOSS) integrated into a Bluefin12 autonomous underwater vehicle was used to collect seafloor sub-bottom data along the TREX reverberation track. BOSS is a downward looking sonar and employs an omni-directional source to transmit a 3 to 20 kHz linear frequency modulated (LFM) pulse. Backscattered signals are received by two 20-channel linear hydrophone arrays. The BOSS survey was carried out to support long-range reverberation measurements at 3 kHz. The data were beamformed in three dimensions and processed into 10cm x 10cm x 10cm voxel maps of backscattering to a depth of 1 m. Comparison of the BOSS imagery with 400 kHz multibeam sonar imagery of the seafloor allows muddy regions to be identified and shows differences rationalized by the differences in sediment penetration of the two frequency ranges utilized. Processed BOSS data are consistent with observations from diver cores and the reverberation data collected by stationary arrays deployed on the seafloor. Specifically, stronger and deeper backscattering from muddy regions is observed (relative to near-by sandy regions). This correlates well with the large amounts of detritus (e.g., shell fragments) and complicated vertical layering within cores, and the enhanced reverberation, from those regions. [Work supported by ONR.]