Abstract:We use the regional-scale double-difference tomography method to perform a joint inversion of the source location and velocity structure of the seismic events recorded from October 2008 to April 2020 in the Haicheng-Xiuyan area of Liaoning province. After excluding the discrete travel time, a total of 5,028 seismic events are collected for positioning. We determine that the average value of the root mean square residual error of the seismic phase travel time decreases from 0.507 s before positioning to 0.279 s after positioning. The results of the relocation show: 1) Most of the earthquakes occurred 5-15 km underground, and the seismic activity in the Haicheng-Xiuyan area was more concentrated in the geological structure and distributed on the fault zone in a strip form, which is similar to the Haichenghe-Dayanghe fault. 2) The main seismic activities we obtain from the inversion are mainly distributed in the low-velocity area and the area at the junction of the high-speed body and the low-velocity body. This is related to the fault structure and deep fluid.
XIA Caiyun,ZHANG Zhengshuai,JIA Lihua et al. Using Double-Difference Tomography to Study the Fine Velocity Structure in Haicheng-Xiuyan Area of Liaoning[J]. jgg, 2022, 42(2): 182-186.