Seismic oceanography study of internal solitary waves in the northeastern South China Sea Basin

In previous work, the internal solitary waves (ISWs) discovered by seismic oceanography are mostly near the Dongsha Island. This paper uses the method of seismic oceanography to find the ISWs in the basin for the first time in the northeastern South China Sea. The pre-stack migration is used to examine the changes of the ISWs structure. It is found that the ISWs waveforms are stable overall during the acquisition period. The shallow reflection of the ISWs has a relatively larger change than the deep. By improving the methods of the predecessors, the ISWs apparent phase velocity is calculated by pre-stack migration profile using the Common Offset Gather (COG). The fitting curve of CMP (Common Mid-Point)-shot point pairs using this method has a better linearity than that using Common Offset Gather directly. The apparent phase velocity of this ISWs using the improved method is 0. 82 m.s(-1), and the apparent direction of the ISWs propagation is from NW to SE (172 degrees N, 0 degrees pointing north).