Coseismic and early postseismic deformation associated with the January 2022 Mw 6.6 Menyuan earthquake, NE Tibet, revealed by InSAR Observations

The 7 January 2022 M-w 6.6 Menyuan earthquake struck the Qilian-Haiyuan fault zone, NE Tibet, offering a chance for understanding the regional seismogenic structure and rupture behavior. We use Interferometric synthetic aperture radar data to study the coseismic and early postseismic deformation of the event. Coseismic modelling highlights that the earthquake activated two strike-variable high-angle strike-slip faults (one SE-trending main fault and one ENE-striking secondary fault) corresponding to only part of the Lenglongling and Tuolaishan faults. Further postseismic analysis not only reveals a localized postseismic signal of up to similar to 3 cm related to the mainshock but identifies an obvious coseismic signal of up to similar to 2.3 cm associated with an M-W 5.1 aftershock characterized by sinistral strike-slip-faulting. The 2022 Menyuan earthquake, large aftershock and 2016 M-w 5.9 thrust-faulting Menyuan earthquake illuminate a positive flower structure of the Lenglongling fault. By a joint analysis of the inversions, fault kinematics and historical earthquake, we suggest that fault branches and low pre-stress jointly restrain the maximum rupture size in the 2022 Menyuan event.

Automated summary

The Menyuan earthquake on January 7, 2022 in northeastern Tibet provided insights into the regional seismogenic structure and rupture behavior. Analysis of the coseismic and postseismic deformation revealed the activation of two strike-slip faults and the presence of significant aftershocks. By combining inversion analysis, fault kinematics, and historical earthquakes, it was found that fault branches and low pre-stress play a role in controlling the maximum rupture size of the Menyuan event.