Measurements of High-Frequency Acoustic Scattering from Glacially-Eroded Rock Outcrops

TitleMeasurements of High-Frequency Acoustic Scattering from Glacially-Eroded Rock Outcrops
Publication TypeJournal Article
Year2016
AuthorsOlson, DR, Lyons, AP, Sæbø, TO
JournalJournal of the Acoustical Society of America
Volume139
Pages1833-1847
Date PublishedApril 2016
Keywordsacoustic seafloor scatter rock

Measurements of acoustic backscattering from glacially eroded rock outcrops were made off the coast of Sandefjord,Norway using a high-frequency synthetic aperture sonar (SAS) system. A method by which scattering strength can be estimated from data collected by a SAS system is detailed, as well as a method to estimate an effective calibration parameter for the system. Scattering strength measurements from very smooth areas of the rock outcrops agree with predictions from both the small-slope approximation and perturbation theory, and range between 33 and 26 dB at 20 grazing angle. Scattering strength measurements from very rough areas of the rock outcrops agree with the sine-squared shape of the empirical Lambertian model and fall between 30 and 20 dB at 20 grazing angle. Both perturbation theory and the small-slope approximation are expected to be inaccurate for the very rough area, and overestimate scattering strength by 8 dB or more for all measurements of very rough surfaces. Supporting characterization of the environment was performed in the form of geoacoustic and roughness parameter estimates.

DOI10.1121/1.4945589
Refereed DesignationRefereed