How do inertia, free surface interaction, and absolute friction coefficient level affect the final slip amplitude in a theoretical earthquake rupture model?
Abstract
Estimating the fault slip amplitude for a future large earthquake is a key problem in earthquake physics with important implications for mitigating earthquake hazards. Theoretically, one can estimate the fault slip with a mechanical model: when initial conditions are given, the corresponding fault slip can be calculated by solving the equations of fundamental physical laws.
Although advancements in computational power have allowed us to simulate earthquakes of great complexity, simplified "generic" models are still widely used as they can provide clear physical insights into earthquake processes. One classic example is the static crack model with a planar fault embedded in an unbounded elastic whole space. This model yields the result that fault slip is proportional to the shear stress change before and after the event (often referred to as "static shear stress drop") and to the length of the rupture/slipping region. In such a simple model, there is no normal stress change due to the slip process. Nonetheless, there are many other parameters to consider other than "static shear stress drop" and "rupture length". For example, when considering inertial effects, the final slip is typically larger than in a static model (known as dynamic overshoot). Most importantly, the classic whole space model suggests that the absolute level of friction coefficient and the absolute level of stress does not affect the final slip amplitude; however, for a dipping fault that ruptures close to the ground surface, the topography can induce a normal stress interaction that in turn can alter the shear stress on the fault through friction coefficient.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMS036.0007W
- Keywords:
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- 7209 Earthquake dynamics;
- SEISMOLOGY;
- 7215 Earthquake source observations;
- SEISMOLOGY;
- 7230 Seismicity and tectonics;
- SEISMOLOGY;
- 8118 Dynamics and mechanics of faulting;
- TECTONOPHYSICS