Abstract:

The authors analyze the essential energy loss during sediment acoustic measurement process, describe the principle of differential attenuation measurement that is the research base of parallel-axis and vertical-axis differential distance attenuation measurement methods, and deduce its attenuation coefficient formula. According to sectioning characteristics of the cylinder seafloor sediment samples from the South China Sea, a coaxial differential distance attenuation measurement method (CDDAMM) is put forward with combination of the above two methods, which is reasonable in principle and feasible in practice. Using CDDAMM, they measure the sound propagation signals of the sediments in both room and controlled temperatures, calculate the acoustic attenuation coefficient, and study the effect of temperature on sound propagation energy. The sound attenuation characters of deep-water seafloor sediments from the South China Sea are as follows. The sediments have large acoustic attenuation coefficients with high sand contents. As temperature increases, the attenuation coefficients vary nonlinearly and inhomogenously, with a descending trend on the whole. This research has provided both data and method for acoustic remote measurement and inversion of physical and mechanical properties of seafloor sediments.

Key words: South China Sea')">South China Sea, Sediments, Temperature, Attenuation