Characterization of Underwater Air Gun Sound Propagation Modes in the Shanwei Region

This study examines the impact of different seawater and seafloor characteristics on the propagation modes using the fluid-solid coupled modal equation. The dispersion curves show the variations in the propagation modes. The findings suggest that the impact of seawater and seabed density is limited, with the seabed P-wave velocity having a lesser influence and the S-wave velocity having a significant impact. Thus, accurately calculating the speed of sound in the seafloor is needed for dependable modal computations. During the extended transmission of waves generated by underwater air guns, three separate wave packets detected by ocean bottom seismometers (OBSs) correspond to the bottom P-wave, S-wave, and direct water wave. The velocity of sound can be deduced from the times at which these wave packets arrive. A study conducted in the vicinity of Shanwei City has established that the predominant route for air gun propagation is through the first-order normal mode.