Abstract：We use GPS observations from 1999 to 2021 to study the crustal deformation characteristics in the area near the epicenter of the 2022 Menyuan 6.9 magnitude earthquake. The velocity field shows an obvious characteristic of ‘big in the south and small in the north’ on both sides of the Qilianshan-Haiyuan seismic belt. The results of the velocity profile of the seismogenic fault show that the extrusion rate on both sides of the fault is 3.1 mm/a, the strike-slip rate is 3.9 mm/a. These results are consistent with the strike-slip-dominated focal mechanism solution. This earthquake is in the gradient zone, which transitions from the high-value area to the low-value area of the principal strain rate field and surface expansion rate field. The earthquake occurred at the edge of the high value area of the maximum shear strain rate field and the second tensor invariant of strain rate. The coseismic Coulomb stress triggers most of the aftershocks and has a certain stress loading effect at the area from the Lenglongling fault to the Haiyuan fault. Based on the analysis results of crustal deformation characteristics and Coulomb stress, we think that the seismic risk of the area from the Lenglongling fault to the Haiyuan fault has been certainly improved.
LU Xiaofei,TAN Kai,ZHANG Caihong et al. Study of the GPS Deformation Characteristics of the Menyuan M6.9 Earthquake in 2022[J]. jgg, 2023, 43(4): 387-391.
