Yongsheng Li

and 8 more

A Mw 6.6 earthquake struck Menyuan, Qinghai, China, on January 7, 2022. To determine the rupture parameters and the seismogenic environment, we resolve the optimal rupture parameters and discuss the tectonic implications of this earthquake event. The Coseismic InSAR deformation maps suggested a maximum of ~80 cm distributed in the light-of-sight direction of the satellite on the southern side of the fault and a maximum of ~70 cm on the northern side. We further estimated the focal mechanism by building a two-segment sinistral strike-slip fault model. The best-fitting solution emphasized that the 2022 Menyuan earthquake ruptured at the junction of the Tuolaishan fault and the Lenglongling fault. Both rupturing faults were dominated by the sinistral strike-slip, and the main slip was concentrated at the shallow part of the rupture plane. The latter is the main rupture segment with a strike of 106{degree sign} and a dip of 86{degree sign}. The slip has mainly occurred at depths of 0-8 km, and the rupture was exposed to the surface. The maximum slip reached ~3.5 m, which was mainly distributed at a depth of 4 km. Jointed analysis of optimal slip model, relocated aftershocks, Coulomb stress change, and field observation suggested that the strain energy in Tuolaishan fault may not be fully released and needs further attention. Moreover, the 2022 Mw6.6 Menyuan earthquake caused a significant stress loading effect on the western Tuolaishan fault and eastern Lenglongling fault, which implied that the 2022 event had strengthened the seismic risk in these regions.