Crustal dynamics prediction and characterization for the Yishu fault zone based on slip susceptibility analysis

We estimate the slip susceptibility of faults in the Yishu fault zone using a slip tendency analysis based on coupled tectonic stress profiles. Studying in situ stress data and focal mechanism solution data collected in this area over more than 30 years, we construct the stress profiles of the study area using the coupling analysis method for deep and shallow stress data. Subsequently, the susceptibility of faults to slip is comprehensively evaluated based on various stress indicators and other related factors. Our results show that the frictional characteristic index μm is low in the deep and shallow crust of the Yishu fault zone, indicating a low degree of overall stress accumulation. A comprehensive evaluation of the susceptibility of faults to slip based on five typical factors (μm, horizontal-to-vertical stress ratio K, angle between the P axis and fault plane θ, S-wave velocity, and seismic density) indicates that the overall seismic risk in the central part of the Yishu fault zone is low, while the northwestern Yishu fault zone exhibits high seismic risk. Furthermore, the southeastern part of the Yishu fault zone reflects the transition from medium- to low-seismic risk. These results provide geomechanical and fault mechanics evidence for evaluating the regional crustal dynamics of the Yishu fault zone.