[S-CG44] Science of slow-to-fast earthquakes

[SCG44-11] Investigation of Scaling Laws for Earthquake Source Parameters Using Simulations of Dynamic Rupture with a Hierarchical Patch Structure

*Kazuki Masuda¹, Yoshihiro Kaneko¹ (1.Kyoto University)

Keywords:Dynamic rupture, Hierarchical patch structure, Scaling laws

Understanding the processes of earthquake rupture growth and the resulting seismic radiation is important for seismic hazard and disaster mitigation. Although scaling laws of source parameters are often used to constrain the physical processes of earthquake rupture growth, whether scaling laws result from the feature of a friction law or the heterogeneity of the physical property has not been fully understood. Here we test a hypothesis that models of spontaneous dynamic ruptures on faults characterized by hierarchical patches of fracture energy Gc in the framework of a slip-weakening friction law can explain several, well-known scaling relations for earthquake source parameters. Our modeling approach is based on a spectral element method and incorporates an efficient, renormalization procedure proposed by Aochi and Ide (2003). We simulate earthquakes with a wide range of magnitudes (M2 to M6) on a simplified one-dimensional fault characterized by hierarchical patches of fracture energy Gc. We then quantify and examine various scaling laws for simulated source parameters, such as seismic moment versus source duration, magnitude-frequency relations, moment growth versus time, and fracture energy versus coseismic slip. We analyze how these scaling laws change as the model parameters are varied. Among the model parameters tested, the so-called seismic ratio (S ratio) has the largest influence on the trend of scaling laws, which suggests that the scaling laws may be used to constrain the underlying model parameters. We will report our efforts on identifying key model parameters on the resulting scaling laws and extending our model procedure to two-dimensional faults.