Modeling acoustic volume backscatter from two shallow-water marine environments by side-scan sonar

The authors use X-ray computed tomography (CT) of cores to provide three dimensional seafloor descriptions on scales much smaller than 1 cm ³. This scale of description is very relevant to sediment internal volume scattering at acoustic frequencies of 10-100 kHz. Statistical characterization and modeling is carried out in two selected environmental regimes: a region of seafloor that is gassy and a region of seafloor that is filled with shell hash. Characterizations of these two seafloor types based on the high-resolution environmental data sets are incorporated into forward models of scattering behaviour and comparisons are made between the various scattering mechanisms. Volume scattering strength predictions in the gassy sediment of Eckernfoerde Bay indicates that scattering from free gas bubbles will dominate that due to continuum variations even for the highest estimate of density and compressibility variance. Predictions of scattering strength versus grazing angle made for the shell hash sediment of the Louisiana continental shelf show that shell hash scattering tan in some instances be at the same level as the the very strong water-sand interface scattering