In situ measurements of sediment sound speed in the frequency band of 2–10 kHz at target and reverberation experiment site

Abstract

As part of the environmental measurements for TREX13 (Target and Reverberation EXperiment 2013), in situ measurements of surfacial sediment sound speed were carried out off Panama City, Florida, using a system called Sediment Acoustic-speed Measurement System (SAMS). SAMS consists of ten fixed sources positioned just above the seafloor, and one receiver which is driven into the seabed to a known depth. During TREX13, 10 deployments were made along the main reverberation track which is about 7.5 km in length. All measurements were made at a penetration depth of 3m between 2 to 50 kHz, focusing on 2–10 kHz. Preliminary sediment sound speed results show variation from low sound speeds (muddy sites) to high sound speeds (sandy sites). A 3–5% of dispersion was observed at coarse sandy sites between 2 and 10 kHz, whereas little dispersion was observed at muddy sites. [Work supported by ONR.]