Experimental Studies of Sound Attenuation in Seabed Sediments on Column Sample Length Scale

Abstract

Seabed sediment microstructure has an influence on its acousto-physical properties, and the properties in a length of the sediment column reflect an aspect of the macroscopic behavior of the microstructure. An original measurement method of the sound attenuation within small distance cross sections in a sediment column, and the corresponding approach in data processing to attain an attenuation factor are detailed in the paper. This method was used to measure the compressional wave in series of points with a small distance in the sediment column, and it is shown that exponential attenuation is a type of compressional wave attenuation model for a sediment column in its full length. It indicates that there are various models of compressional wave attenuation in seabed sediments in the South China Sea after comparison of data from other literature. The method of measuring sound attenuation satisfies the sampling space interval in the acoustical forward and inverse problems in seabed sediments, and the original method provides a new approach for finding out sound attenuation mechanism in seabed sediments on small length scale.

Keywords:

• acoustic attenuation measurement
• column sample length scale
• seabed sediment
• small distance
• sound attenuation

Acknowledgments

Most of the work reported here was carried out in a project supported by Key Laboratory of Marginal Sea Geology, Chinese Academy of Sciences, project No. MSGL09-04, and additionally supported by the China National Natural Science Foundation, project No. 40876018 and No. 41176034, and from State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, project No. SKLOA201003.

Further, this work could not have been completed without the help of Professor Bo Lu, South China Sea Institute of Oceanology, Chinese Academy of Sciences. Thanks also to Audiowell Electronics (Guangzhou) Co., Ltd. supporting ultrasonic sensors made of bending piezoelectric diaphragms.

Notes

ND expresses no datum.