The 3-D structure of shear waves in the crust and mantle of east continental China inverted by Rayleigh wave data

The phase velocity dispersion of seismic surface waves have been calculated on the basis of clear and reliable Rayleigh wave records of the 21 seismic stations and 43 paths in east continental China. A distribution of phase v elocity dispersion is obtained by Talantola probability inverse method. The image of the distribution of 3-D shear wave velocity in the crust and mant le is inverted by the phase velocity dispersion curves in the researched ar ea. Then we obtain the S velocity structure in the cruse and mantle of east continental China. The results show that the overall tendency of the thick ness of east China crust is thin in the east and thick in the west. To the west of 105 degrees E, thickness of the crust gradually increases to 55km. There is an 'h' form slope belt of the crust thickness. The crust is relati vely thin in west Henan province and south Shanxi province. The thickness o f the crust beneath Dabie mountain and Tai mountain is thicker than surroun ding area. But the crust is not thicker beneath Qin mountain (Qinlin). In N orth China the top interface of the low velocity layer of the upper mantle is rather shallow. It is about 80-90km. In the area of Eerduosi depression, Sichuan syneclise and Cuizhou-Hunan area it is about 120-130km. In the eas t Yangtze block as well as middle and South China Folding System velocity i n the top upper mantle is relatively low and the velocity contrast of low v elocity layer is not evident. In the west of Yunnan-Guizhou folding system there is no low velocity layer within the top 200km of the upper mantle.