Spontaneous Dynamic Rupture Simulation on Geometrically Complex Faults Governed by Different Friction Laws

Bin Luo, & Benchun Duan

Submitted August 14, 2016, SCEC Contribution #6819, 2016 SCEC Annual Meeting Poster #048

The constitutive law describing how friction resistance evolves dynamically on the existing shear fault surface is one of the major factors controlling the behavior of dynamic earthquake rupture. The laboratory-derived rate- and state- friction laws have been widely applied in spontaneous dynamic rupture modeling and behave similarly to the standard slip-weakening friction law on a flat fault model. However, when geometrical complexity is introduced to the fault surface, rupture behavior obeying different friction laws may be affected differently by these geometrical irregularities. Using our explicit, dynamic finite element method code EQdyna, we carry out multiple spontaneous dynamic rupture simulations on both planar and non-planar faults governed by slip-weakening law(SW) and rate- and state- friction laws including ageing law(RS-A), slip law(RS-S) and slip law with flash heating(RS-FH) for comparison to explore the differences between their associated rupture behaviors. Our result suggests that models with all kinds of friction laws applied here share common, friction-law-independent features of geometrical effects on rupture behavior, such as local static stress alteration, dynamic unclamping on extensional sides and clamping on compressional sides of bulging bumps on the fault surface. Nonetheless, different friction laws provide different description of the yielding process in response to stress heterogeneity induced by non-planar geometry, resulting in different level of geometrical impact on rupture propagation. Compared to the model with SW, those models with rate- and state- friction at low velocity levels (RS-A and RS-S) show geometrical effects to a lesser extent, while the one with RS-FH inducing pulse-like rupture instead of crack-like rupture shows much stronger geometrical impacts on rupture propagation.

Key Words
dynamic rupture, non-planar fault, various friction laws

Citation
Luo, B., & Duan, B. (2016, 08). Spontaneous Dynamic Rupture Simulation on Geometrically Complex Faults Governed by Different Friction Laws. Poster Presentation at 2016 SCEC Annual Meeting.


Related Projects & Working Groups
Fault and Rupture Mechanics (FARM)