Seafloor Sediment Acoustic Properties on the Continental Slope in the Northwestern South China Sea

• Published in: Journal of marine science and engineering Vol. 12; no. 4; p. 545
• Main Authors: Li, Guanbao, Wang, Jingqiang, Meng, Xiangmei, Hua, Qingfeng, Kan, Guangming, Liu, Chenguang
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.04.2024
• Subjects: Acoustic propagation; Acoustic properties; Acoustics; Attenuation; continental shelf; Continental slope; Deep sea; Deep sea sediments; Deep water; Direction; Distribution patterns; Empirical equations; Environmental factors; Experiments; Grain size; In situ measurement; Laboratories; Measurement techniques; Ocean floor; Particle composition; Particle size; Physical properties; Porosity; Rivers; Seawater; Sediment; Sediment samplers; Sediment samples; Sediment sampling; Sediments; Shallow water; Shelving; Slopes; sound speed; Sound velocity; Spatial distribution; Underwater acoustics; Underwater communication; Variation; Water depth; Wave propagation; South China Sea; China; Pacific Ocean; Red River; Hainan Island
• ISSN: 2077-1312; 2077-1312
• DOI: 10.3390/jmse12040545

The acoustic properties of seafloor sediments on continental slopes play a crucial role in underwater acoustic propagation, communication, and detection. To investigate the acoustic characteristics and spatial distribution patterns of sediments on the continental slope, a geoacoustic experiment was conducted in the northwestern South China Sea. The experiment covered two sections: one crossing the shelf and slope in the downslope direction, and the other near the shelf break in the along-slope direction. In situ techniques, sediment sampling, and laboratory measurements were used to acquire data on sediment acoustic properties (such as sound speed and attenuation) and physical properties (including particle composition, density, porosity, and mean grain size). The experimental findings revealed several key points: (1) Acoustic properties of shallow water coarse-grained sediments and deep-sea sediments were higher when measured in the laboratory compared to in situ measurements. (2) Relationships between measured attenuation and physical properties, as well as between sound speed and mean grain size, showed deviations from previous empirical equations. (3) Sediment acoustic and physical properties exhibited significant variations in the downslope direction, while showing gradual variations in the along-slope direction. These variations can be attributed to sedimentary environmental factors such as material sources, hydrodynamic conditions, and water depth.