Fault strength and rupture process controlled by fault surface topography

• DOI: 10.1038/s41561-022-01093-z
• Publication Date: 2023-01-02T17:02:56Z
• Authors: Shiqing Xu; Eiichi Fukuyama; Futoshi Yamashita; Hironori Kawakata; Kazuo Mizoguchi; Shigeru Takizawa
• Keywords: Stress field

Faults are rarely completely smooth, with topographic undulations coming from the distribution of asperities along fault surface. Understanding effects surface topography on strength and earthquake source properties has been limited due to a lack in situ observations field. Here we use simulated cycles metre-scale laboratory faults show degree heterogeneity, especially macroscopic peak represented by shear force required commence failure. Our results demonstrate that less heterogeneous is weaker, its lower strength, produces larger stress drop average than more fault. Rupture tends propagate at subshear speed while accommodates wider range rupture speeds, including slow slip supershear rupture. These reveal how heterogeneity affects initiation during propagation, which important implications for understanding natural earthquakes. Simulated earthquakes surfaces stronger, propagation those heterogeneous.