Dynamic Modeling of Potential Earthquake Rupture Paths through Cajon Pass, Southern California
Abstract
Cajon Pass is the site of a complex junction of several active major faults. The right-lateral strike-slip San Jacinto fault splays off southeastward from the throughgoing, right-lateral strike-slip San Andreas fault. The Cucamonga thrust fault approaches both strike-slip faults, and likely penetrates and offsets them, bringing sections of the San Andreas and San Jacinto closer together than their apparent surface separation of 1.5 km. Due to the number of active faults in the Cajon Pass area and their proximity to densely populated urban southern California, the seismic hazard and risk from ruptures in the pass is high. We use dynamic rupture modeling to determine possible rupture behaviors and lengths for Cajon Pass earthquakes, with particular focus on understanding interactions that may lead to or inhibit joint rupture of two or more faults in a single event. We incorporate realistic fault geometry, initial stresses, and surrounding geology into these models. Models incorporating only the San Andreas and San Jacinto faults tend to produce multi-fault rupture from a number of nucleation points. We also investigate how the cross-cutting Cucamonga thrust may affect rupture patterns on all three faults.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.S13E..08L
- Keywords:
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- 4314 Mathematical and computer modeling;
- NATURAL HAZARDSDE: 7209 Earthquake dynamics;
- SEISMOLOGYDE: 8118 Dynamics and mechanics of faulting;
- TECTONOPHYSICSDE: 8163 Rheology and friction of fault zones;
- TECTONOPHYSICS