5:15 PM - 7:15 PM
[SSS11-P20] Seismic Hazard Analysis in the Tianzhu Seismic Gap Based on Interseismic Locking and Rupture Dynamics
Keywords:Fault locking, Slip deficit, Tianzhu seismic gap, Dynamic rupture simulation, Strong ground motion simulation
The Tianzhu seismic gap, located at northeastern margin of the Tibetan Plateau, is an important segment of the Haiyuan fault system. In recent years, multiple earthquakes have occurred on both sides of the gap, yet no significant seismic event has been observed within it for the past several centuries. Given the high slip rate of the region, there is a considerable likelihood of a large earthquake occurring, making it crucial to analyze its seismic hazard. In order to simulate a more realistic earthquake rupture process, we constrain the calculation of the heterogeneous stress distribution based on fault locking. We combine the fault locking distribution and slip deficit rate, along with the interseismic stress accumulation time, to calculate the stress accumulation on the fault plane. Based on this, we simulated the dynamic rupture process and strong ground motion of the Tianzhu seismic gap. Inversion results indicate the presence of strong locking zones within the Tianzhu seismic gap, which poses a high seismic risk. Dynamic simulation results suggest that the region is likely to occur an earthquake with a magnitude of Mw 7.3-7.4, with a maximum intensity of Ⅺ. To thoroughly analyze the potential rupture scenarios in this region, we conducted simulations based on the rupture results under a maximum slip deficit rate of 5 mm/yr. Under these conditions, the earthquake magnitude could reach up to Mw 7.5. This study provides a method for quantitatively analyzing the potential seismic hazard and reveals a high seismic hazard potential in the Tianzhu seismic gap.