Sound speed and attenuation in marine mud seabottom

Abstract

Acoustic propagation in shallow water is greatly influenced by the properties of the bottom. Comparing the acoustic characteristics in the sediments of sand or silty are well inverted or directly core measured, sound speed and attenuation in the mud sediment still need investigated further. An experiment was performed in the Yellow Sea in 2002 to inversion for the acoustic parameters. In the experiment, six different sediment types: Fine Sand, Silty Sand, Sand Silty, Sand-Silty-Clay, Silty Clay and Mud, are included in an area. A hybrid geoacoustic inversion scheme, which combines several inversion methods together to invert for the bottom parameters, is proposed based on the fact that the bottom acoustic parameters have different sensitivities to the different physical parameters of acoustic field. The inverted bottom parameters could distinguish the atlas marked bottom type quite well. The sound speed and attenuation parameter in the marine sediments of silty clay and mud is mainly discussed. The nonlinear frequency relationship of attenuation in the mud is compared with that of silty sand. [Work supported by the National Natural Science Foundation of China under Grant No. 11434012 and Grant No. 41561144006.]