Studies in Western U.S. Geodynamics

University Of Oregon Eugene, Eugene OR

Investigators

Abstract

Intellectual Merit: Three regional studies will address the processes responsible for the tectonic behavior in each region. The study areas are: 1) Southern California. Study will focus on the cause of mountain building in the transform-fault environment of the San Andreas fault; 2) the Sierra Nevada. Study will focus on the tectonic strengths of the bounding San Andreas fault and eastern California shear zone and on the nature of the gravitationally driven extension of the Basin and Range; and 3) the Pacific Northwest. Study will focus on the interplay between the shear tectonics imposed by Pacific-North America interaction and the subduction margin, which varies from weakly to strongly compressive. These regional studies will be modeled in a manner consistent with plate scale stresses and will be used to improve the current plate scale dynamic model. The proposed research will be accomplished in two and three dimensions with a finite element computer simulations that incorporate faults, viscous and plastic rock deformation mechanisms, and gravity-driven processes in realistic ways. This project will produce results that will help to understand the relative importance of plate interaction and internal buoyancy driven continental deformation. Also, improved models of the distribution and rate of deformation will be produced based on geodetic and geologic faulting data. These results will be used both to evaluate the quality of the computer simulations and to constrain lithospheric strength. Broader Impacts: Results will help constrain the strength and behavior of faults, which is important to understanding earthquake processes. This project will prepare a graduate student for the future through collaborations, participation in a diverse set of disciplines, and integration of the range of findings into consistent results. It also will help foster an international collaboration.