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Access Type
Open Access
Document Type
thesis
Degree Program
Geosciences
Degree Type
Master of Science (M.S.)
Year Degree Awarded
2009
Month Degree Awarded
February
Keywords
San Andreas, San Jacinto, Model, Slip Rate, Uplift
Abstract
The San Andreas fault forms the right lateral transform boundary between the North American and Pacific tectonic plates. At various locations along the San Andreas fault the geometry of the fault surface is much more complex than a straight, vertical, plane. The San Bernardino Mountain segment of the San Andreas fault, in the San Gorgonio Pass region has one of the most complex active fault geometries in southern California due to a left-stepping restraining bend in the San Andreas fault. The evolution of the actively faulting pass has created an intricate network of active and formerly active, dipping and vertical, three-dimensionally irregular fault surfaces. The purpose of this research is to gain a better understanding of the mechanics of the present day active fault geometry and the evolution in the San Gorgonio pass region, through numerical modeling. We use the three-dimensional Boundary Element Method modeling code Poly3D to simulate different fault configurations. We see that fault geometries that include geologically observed and inferred fault dips match geologic data more accurately than simplified, vertical faults in the San Gorgonio Pass region of the San Andreas fault. The evolution of the San Andreas Fault in the San Gorgonio Pass region over the past million years may follow the principle of work minimization in the Earth’s crust up until the present day configuration.
DOI
https://doi.org/10.7275/695257
First Advisor
Michele L. Cooke