The Estimation Of Effective Elastic Thickness Based On The Coherence Method In South China Sea

The effective elastic thickness is a physical quantity based on the lithospheric elastic sheet model and characterizes the stiffness of a long time lithosphere.The Te is widely used to explain the large-scale structure and movement of the lithosphere due to the multiple factors such as the thermal structure,age and load of the lithosphere.Studies on the continental lithosphere show that the Te is related to the craton,and has a certain correlation with the density distribution and stress state of the lithosphere.The Te of the oceanic lithosphere is mainly controlled by the thermal structure of the lithosphere and the age at which the load is formed.At present,the study of Te in China is mainly concentrated in the continental lithosphere.The calculation and interpretation of the Te in the marine area are not enough and need to be further developed.The South China Sea is the edge of the western Pacific Ocean.It is located at the intersection of the Eurasian Plate,the Pacific Plate,and the Indo-Australian Plate.The center has developed dilated ridges.The geological structure of the South China Sea is complex and the plate interaction is obvious.Therefore,studying the Te of the area can provide evidence for the structure and dynamics of the lithosphere.Most of the Te in the South China Sea is small,indicating that it is basically in the Airy equilibrium state.This is consistent with previous studies.The Te increases in the Manila trench and in the southwest direction due to the load on Luzon and Palawan.The Te increases in the northern part of the South China Sea.The rigidity of the lithosphere gradually increases because the area transforms from the oceanic crust to the continental crust.The effective elastic thickness of the oceanic lithosphere in the South China Sea has a negative correlation with surface heat flow.The relationship between effective elastic thickness and seismic volcanic distribution in the South China Sea is approximately positively correlated.