Sediment sound speed measurements using buried vector sensors

• Published in: The Journal of the Acoustical Society of America Vol. 119; no. 5_Supplement; p. 3445
• Main Authors: Lyons, Anthony P., Osler, John C., Chapman, David M. F., Hines, Paul C.
• Format: Journal Article
• Language: English
• Published: 01-05-2006
• Subjects: Marine; ASW, USA, Florida; ASW, Mexico Gulf
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.4786957

As part of the SAX04 sediment acoustics experiment conducted off the coast of Florida in the Gulf of Mexico, vector sensors containing three-axis accelerometers and pressure sensors were buried in the seabed. These sensors were used as the receivers to measure sediment sound speed dispersion from 300 to 3000 Hz a band in which it has been particularly difficult to make these measurements. The acoustic intensity measured by the vector sensors was combined with the experimental geometry and propagation conditions, to relate the angle of arrival to sediment sound speed as a function of frequency. Lower frequency measurements, 300 to 1200 Hz, used noise radiated from a moored research vessel as the acoustic source. Higher frequency measurements, 800 to 3000 Hz, used transmissions from an acoustic projector in a three-point mooring in the water column that could be adjusted to change the angle of ensonification. Results from the two techniques are compared with each other and previous measurements of dispersion in sandy sediments. [Work performed under ONR Grants N00014-04-1-0013 and N00014-03-1-0883.]