Rayleigh Wave Dispersion And Three‐Dimensional Velocity Structure in the Continent And Its Margin of Southeastern China

Abstract

AbstractWith the matched‐filter of using frequency‐time analysis (FTAN) technology, we process the Rayleigh wave data recorded by China seismic stations, and then obtain the dispersion of Rayleigh wave of crossing southeastern China continent and margin belt. We obtain pure path dispersion data of 40 × 40 grid for the southeastern China continent and margin belt by using a stochastic method. Based on the gridding inversion, we obtain the three‐dimensional velocity structure for shear wave velocities by using the surface wave inversion program of Harkrider. The result indicates that: 1. The Moho depth of Southern China continent is 30–40 km and becomes thinner from west to east. At the margin and shallow sea region the Moho depth is 25–28 km and shows a clear zonal pattern. 2. The buried depth of low‐velocity layer in upper mantle lies between 60 to 150 km and exhibits strong lateral variation related to the distribution of deep faults and deep internal dynamic processes. The undulatory variation of the interface in the NS direction is flatter than that in theWE direction. 3. The margin of the southeastern continent is the sea‐continent transition belt of the East Asia continent. The depth of the Moho interface is shallow and the average velocity in the crust is low. The undulation behavior of the deep mantle interface indicates the heterogeneity of the structure and the coupling affect of deep and shallow medium.