Geoacoustic characterization of seabed scattering experiment locations

Abstract

Measurements of acoustic forward and backscattering have been made by DRDC Atlantic during collaborative sea-trials on the Scotian Shelf off the coast of Nova Scotia and on the Strataform site off the coast of New Jersey. In this paper, the geoacoustic properties and roughness parameters that are necessary to interpret and model the scattering measurements are presented. They have been determined using complementary in situ and acoustic techniques. The in situ measurements have been made using grab samples and a free fall cone penetrometer that has been fitted with a resistivity module. The probe provides two independent means of calculating the undrained shear strength, an empirical sediment classification and sediment bulk density. The acoustic measurements include inversions for geoacoustic parameters using the WARBLE [Holland and Osler, J. Acoust. Soc. Am. (2000)] and normal incidence sediment classification [Hines and Heald, Proc. Inst. Acoust. (2001)] techniques. At the scattering experimental locations, these measurements have been combined with surveys using commercial equipment: sidescan sonar, multibeam bathymetry, and subbottom profilers to characterize the seabed.