地震学报（英文版）2007，Vol.20Issue(4)：359-369,11.
Middle and upper crust shear-wave velocity structure of the Chinese mainland
Middle and upper crust shear-wave velocity structure of the Chinese mainland
摘要
Abstract
In order to give a more reliable shallow crust model for the Chinese mainland, the present study collected many short-period surface wave data which are better sensitive to shallow earth structures. Different from traditional two-step surface wave tomography, we developed a new linearized surface wave dispersion inversion method to directly get a 3D S-wave velocity model in the second step instead of inverting for 1D S-velocity profile cell by cell. We convert all the regionalized dispersions into linear constraints for a 3D S-velocity model. Checkerboard tests show that this method can give reasonable results. The distribution of the middle- and upper-crust shear-wave velocity of the Chinese mainland in our model is strongly heterogeneous and related to different geotectonic terrains. Low-velocity anomalies delineated very well most of the major sedimentary basins of China. And the variation of velocities at different depths gives an indication of basement depth of the basins. The western Tethyan tectonic domain (on the west of the 95°E longitude) is characterized by low velocity, while the eastern Tethyan domain does not show obvious low velocity. Since petroleum resources often distribute in sedimentary basins where low-velocity anomaly appears, the low velocity anomalies in the western Tethyan domain may indicate a better petroleum prospect than in its eastern counterpart. Besides, low velocity anomaly in the western Tethyan domain and around the Xing'an orogenic belt may be partly caused by high crustal temperature. The weak low-velocity belt along ～105°E longitude corresponds to the N-S strong seismic belt of central China.关键词
surface-wave tomography/ shear-wave velocity/ sedimentary basins/ shallow crust/ ChinaKey words
surface-wave tomography/ shear-wave velocity/ sedimentary basins/ shallow crust/ China分类
天文与地球科学引用本文复制引用
FENG Mei,AN Mei-jian..Middle and upper crust shear-wave velocity structure of the Chinese mainland[J].地震学报（英文版）,2007,20(4):359-369,11.基金项目
National Natural Science Foundation of China (40504011, 40674058) （40504011, 40674058）
State Special Project of Oil-Gas of the Ministry of Land and Resources (XQ-2004-01). （XQ-2004-01）
