Correlation between dynamic deviatoric stress and seismic activity in the Gansu section along the northeastern margin of the Qinghai-Xizang Plateau

Based on the relative gravity data of southeastern Gansu from 2020 to 2024 and the global gravity field model WGM2012, this paper calculates the horizontal and dynamic deviatoric stress (HDS, DDS) in this region and analyzes its relationship with seismic activity, focusing on the relevant characteristics of the 2023 Jishishan M_S6.2 earthquake in Gansu. The results show that the HDS in the study area is mainly concentrated in tectonically active areas such as the Qilian-Haiyuan Fault Zone and the Qinghai Nanshan-Linxia Fault Zone. Seismic case studies indicate that earthquakes are mostly concentrated in areas with HDS exceeding 7 MPa. The study of the Jishishan M_S6.2 earthquake case shows that the HDS level in the epicenter area is relatively high. From 2021 to 2023, the DDS disturbance in the periphery of the 2023 Jishishan M_S6.2 epicenter intensified, especially in the year before the earthquake, when an arc-shaped high-value DDS zone appeared along the fault strike, suggesting that DDS anomalies may serve as potential indicators in earthquake risk assessment. Furthermore, Significant concentrations of deviatoric stress can still be observed in two high-HDS background areas: the eastern segment of the Tianzhu seismic gap and the southern segment of the Riyueshan fault. Their seismic hazard should be continuously monitored in the future.