Numerical Simulation of the Mechanical Properties of Anninghe - Zemuhe - Xiaojiang Faults in Southwestern China

Abstract:

The southeastern boundary of Chuandian block in southwestern China, i.e. Anninghe-Zemuhe-Xiaojiang fault zone, which is now very active, the earthquake occurred frequently and in segments, strong earthquakes swarmed. In different segments, seismicity, slipping rates are obviously different. Studying the faulting mechanics in segments is important for understanding the rule of seismicity in this fault zone. With the earth interior structure, seismotectonics data, stress field and GPS data, rheology of the lithosphere as constraint conditions, we establish the three-dimensional finite element model of the Anninghe-Zemuhe-Xiaojiang fault zone. Faulting mechanical characters in segments, including the fault inactive, locking, aseismic creeping, stick-slipping and the rupturing, et al., are specified with contact surfaces and weak zone materials in ADINA program; and multi-timescale method is adopted to analyze the rupture in seconds and secular fault creep in tens of thousands of years. Numerical simulation results of the stress, strain and slip rate are used to explore the relationship between earthquakes and the faulting zone activity, and reveal the mechanisms of the faulting mechanical characters in segments.