Fine tomographic inversion of the upper crust 3-D structure around Beijing
WANG Fu-Yun 1, ZHANG Xian-Kang 1, CHEN Qi-Fu 2, CHEN Yong 2 ZHAO Jin-Ren 1, YANG Zhuo-Xin 1, PAN Su-Zhen 1 1 Exploration Geophysics Center, China Earthquake Administration, Zhengzhou 450002, China 2 Institute of Earthquake Science, China Earthquake Administration, Beijing 100036, China
Travel-time data from 3-D Moho reflection survey in 2002 are inverted using seismic tomographic method without blocks. The upper crustal 3-D structure of slowness of P, S wave and V P/V S around Beijing area are given. The slices of three structures in different depths reveal the NE and NW trends of slowness and V P/V S distributions. The upper crustal velocity images are resulted of the sedimental heterogeneity by active seismotectonics in the area. Most of regional earthquakes occurred in low-V P/V S zones, it indicates that earthquake activities are not only related to active faults and may be linked to crustal structure and its material property. There is a close relationship among velocity structure, active faults and upper crustal materials around Beijing area.