Physics-based simulation of seismicity based on fault kinematic models: a case study of the Northern Shanxi Rift, North China

Abstract

Abstract The long-term seismicity inferred from the physics-based simulations provide a valuable complement to limited historical and instrumental records, especially in continental interiors characterized by low-frequency strong earthquake activity. This study presents a detailed long-term (steady-state) slip rate model for major active faults in the northern Shanxi rift, constrained by multi-source geophysical kinematics and inverted using NeoKinema program package. Utilizing our derived fault kinematic model as input for the physics-based seismicity simulator (Virtual Quake, VQ), we simulated the fault-scale long-term seismicity. Our results reveal that the northern Shanxi rift is dominated by horizontal crustal extension with a maximum extension rate of approximately 1 mm/year in the NW direction and associated normal faulting. Active boundary faults trending NEE exhibit relatively high slip rates, ranging from approximately 0.30–0.74 mm/year. In contrast, secondary or buried faults with nearly EW trending orientations generally have lower slip rates, fluctuating around 0.2 mm/year. Notably, the nearly NS-trending faults in the southern region exhibit a significant right-lateral strike-slip motion (~ 0.4 mm/year), while the NW-trending fault zones in the northern region are characterized by predominantly left-lateral strike-slip motion (~ 0.3 mm/year). Statistical analysis of the Coefficient of Variation (CoV) of recurrence intervals in the simulated long-term seismicity indicates that the recurrence intervals of most faults are relatively uniform, except for the east segment of the North Liulengshan fault. The high CoV value for this fault suggests a more pronounced tendency for seismicity clustering. In contrast, the North Hengshan fault exhibits the lowest CoV value, indicating relatively stable seismicity and a quasi-periodic pattern. Correlation analysis between fault slip rates and recurrence interval variability reveals that faults with lower slip rates tend to exhibit stronger clustering behavior, while faults with higher slip rates tend to exhibit a more pronounced quasi-periodic pattern. Seismic hazard analysis based on the conditional probability of strong earthquakes further highlights the significant seismic potential of the North Hengshan fault. The estimated probabilities of strong earthquakes(> M6.5) occurring within the next 100 and 200 years are80% and 96%, respectively, indicating its significant strong earthquake potential in the North Hengshan Fault. Graphical Abstract

Keywords

• Northern Shanxi rift
• Long-term fault slip rate
• Joint inversion
• Physics-based seismicity modeling