Abstract:We use the fixed station network and the Himalayan Phase III array data, and adopt the double-difference tomography method to jointly invert the seismic position and velocity structure of Linfen basin and its surrounding areas, and finally obtain the precise location and velocity structure of earthquakes in the study area. The seismic relocation results show that the Linfen basin earthquakes have two dominant seismic strata(5-9 km and 18-25 km), and there are more earthquakes in the lower layer than the upper layer. The earthquakes have obvious clustering, and the lower boundary of seismogenic layer is clear. The earthquakes below Hongdong depression and Xinzhi uplift are clustered, and the small earthquakes with the deepest focal depth are all concentrated in this area. The velocity structure results show that the shallow velocity gradient in the study area is highly consistent with the exposed geological structure, which confirms the reliability of inversion results. The velocity structure below 12 km is different from the shallow structure, indicating that the regional crust generally presents the inconsistency characteristics between deep and shallow structures. In the early stage of Lingshi uplift, the paleochannels connected Linfen basin and Taiyuan basin, and occurred fault-block dome uplift in the later stage. This study can provide geophysical evidence for that, and speculates that the paleochannels located on western Lingshi uplift. The reason why the seismic belt located on western Lingshi uplift is that the west side has low-velocity structure compared with the east side, and is easy to break under the anticlockwise rotation force of Ordos block. From the surface of Linfen basin to 18 km, the overall low speed and low density structure is presented, which is related to the structural water content. The Linfen 1695 M7 earthquake occurred in the velocity conversion zone, and the Hongtong 1303 M8 earthquake occurred in the high-speed tectonic zone, which shows that the seismogenic structures and mechanisms of the two earthquakes are different.