晋冀蒙交界地区地壳三维P波速度结构及地震活动性研究

2014年9月晋冀蒙临时地震台网正式运行，为晋冀蒙交界地区的地震研究提供了丰富的资料。结合临时台与固定台记录的P波走时资料，采用双差层析成像方法对该区进行地震重定位和三维P波速度结构联合反演，分析该区3个典型盆地的速度扰动结果，结果表明，地震重定位残差显著降低，震源深度分布更加合理；P波速度浅层基本符合平原地区低速、山区高速的特点，深层则有相反表现，典型盆地P波速度在浅层较为复杂，高低速相间，深层表现为低速；研究时段内忻定盆地和延怀盆地地震活动密集，大同盆地地震活动较弱，低速体及边缘地震活动强度高于高速体及边缘。

Reserch on 3D P-wave velocity structure of the crust and seismic activity in the juncture area of Shanxi,Hebei and Inner Mongolia

September 2014, a temporary station network in the juncture area of Shanxi, Hebei and Inner Mongolia was officially put in operation, which provided abundant information for the earthquake research in the area. We did joint inversion of seismic relocation and 3D P-wave velocity structure by double-difference tomography combined with P-wave arrival time data recorded by the temporary stations and the fixed stations in the area. The velocity perturbation results of three typical basins in the area were analyzed. The results show that the residual of seismic relocation is significantly reduced and the distribution of focal depth is more reasonable. The P-wave velocity in shallow is basically consistent with the characteristic that the plain is low velocity area and the mountain is high velocity area, while the reverse in deep. The P-wave velocity in shallow of the typical basin is more complicated, high and low velocity alternatively, and the deep shows low velocity. The seismic activity is dense in the Xinding basin and the Yanhuai basin, and the seismic activity in the Datong basin is weak. The seismic activity in low velocity body and its edge is higher than that in high velocity body and its edge.