Influence of self-similar stresses on scenario earthquake construction: An example along the Tanlu Fault

Abstract

As a famous deep and large fault in eastern China, the Tanlu Fault passes through Anhui, Jiangsu, and Shandong and into northeastern China. It is important to improve the understanding of seismic hazard assessments in areas near faults. We start a scenario earthquake simulation in the M7.5 earthquake potential area of the Xinyi-Sihong segment of the Tanlu Fault. The fault rupture length and width are constrained according to the scaling law of large intraplate earthquakes, the background normal stress is depth dependent, and the initial shear stresses are determined using trial and error by matching the earthquake magnitude. Considering the 120 km rupture length of the M7.5 earthquake, we compare the horizontal uniform stress model and self-similar stress perturbation model. Our findings reveal that the seismic source time function of the horizontal uniform stress model is similar to that of the Haskell model and that of the self-similar stress perturbation model is more similar to that of a real earthquake case. We compare the dynamic rupture simulation and ground motion results under four different stress conditions and find that the shorter the characteristic length of the self-similar function is, the rougher the initial stress. For the M7.5 earthquake with an epicenter in the vicinity of Suqian, the Xinyi-Tancheng segment, which is located in the IX-intensity zone north of the epicenter, vibrates more strongly on the northern side than on the southern side due to the influence of the low-velocity zone and the peak slip rate. The response spectra analysis at stations in the study area is useful for improving the earthquake resistance capability.