New progress has been made in imaging research on the ratio of vertical and horizontal wave velocity in the ocean-continent transition zone of the Zhongsha block

South China Sea Institute of Oceanology edge of the sea and ocean Key Laboratory of Geological ( the OMG ) researcher Qiu Xuelin team of Dr.

The ocean-continent transition zone ( COT ) is a key area for understanding the state of magma supply and the geodynamic mechanism in the process of passive continental margin rifting and rupture to seafloor expansion

The value of Vp/Vs is generally considered to be a key indicator that can effectively reveal the lithological composition, so it is expected to be used to solve the problem of COT structure

In order to accurately determine the COT structure, the researchers took the COT on the south side of the Zhongsha block as an example, using active source submarine seismograph ( OBS ) detection data, proposed a set of S- wave crustal / upper mantle velocity structure inversion method, and obtained Vp /Vs model results

Through verification and comparative analysis with adjacent multi-channel seismic profiles, the researchers revealed that the COT, which may be invaded by magma from north to south, gradually transitioned to the serpentinized mantle structure under the thin oceanic crust

This research provides an example for the acquisition of active source OBS shear wave inversion imaging and Vp/Vs model, and provides new ideas for solving COT structural problems in the future

The OBS data used in this study was collected by the South China Sea Geophysical Shared Voyage Project of the National Foundation of China on the "Experiment 2 " scientific research ship of the South China Sea Institute of Oceanology, Chinese Academy of Sciences.

Related paper information: https://doi.

Figure 1( a ) P- wave velocity structure model; ( b ) S- wave velocity structure model; ( c ) Vp/Vs value model

Figure 2Judgment of lithology by Vp/Vs value distribution