Abstract

The 2022 Menyuan earthquake occurred in the Qilian-Haiyuan fault system in northeastern Tibet. To investigate the reason behind this earthquake and the seismic hazards of the Tianzhu Seismic Gap, we demonstrated the spatiotemporal stress variation on the fault system before and after 2022 through numerical modelling. We found that the 2022 earthquake was delayed due to a stress shadow caused by historical earthquakes. This stress shadow also covers the middle of the Tianzhu Seismic Gap and prohibits its seismic activities to some extent. Acting as a stress barrier to prevent the Tianzhu Seismic Gap rupturing in one event, this stress shadow may decrease the possibility of generating a future earthquake of magnitude more than Mw7.7 in this gap. The east portion of the Tianzhu Seismic Gap was stress loaded, indicating its increased seismic hazards. Attention should be paid to the hazards prevention in the eastern portion of the gap.