Mainshock and Aftershock Sequence Simulations in Geometrically Complex Fault Zones
Abstract
Aftershocks seems to be located along the trace of the mainshock fault, however we do not know their exact location against the mainshock fault due to the location error. We hypothesize that most of aftershocks are rupture of small subsidiary faults instead of the reruptures of the mainshock fault, and they are triggered by the local increase of stress due to the rough geometry of mainshock fault. To explore this scenario, we perform 2-D earthquake sequence simulations considering a rough main fault and numerous subsidiary faults which obey the rate and state friction law. We demonstrate that many aftershocks occur at the side of the main fault, delineating the main fault trace. We also show that the roughness of the main fault decreases the concentration of aftershocks around the tip of the mainshock fault. Our numerical simulation reproduces the Omori-Utsu law for the temporal decay of aftershocks and the expansion of the aftershock zone. The variability of focal mechanisms of aftershocks strongly depends on the friction coefficient. Large aftershocks are limited in the tips of the mainshock fault. This is one of the first earthquake sequence simulation based on the continuum mechanics framework that reproduces realistic spatiotemporal aftershock activities.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMS038.0012O
- Keywords:
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- 7299 General or miscellaneous;
- SEISMOLOGY