Collaborative Research: Self-Consistent Kinematics and Dynamics of the U.S.

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EAR-0001160Holt, William E.The investigators propose to use recent GPS/VLBI/SLR observations, Quaternary fault slip rates, the geoid, crustal thickness variations, and topography data to quantify both the strain rate tensor field and the vertically averaged deviatoric stress tensor field within western North America. Results to date indicate that gravitational potential energy (GPE) differences control the large fault-normal compression observed along the California coast as well as the extension at the Wasatch Range. Deformation in the Basin and Range is driven, in part, by gravitational potential energy differences but the extension directions there are strongly modified by plate interaction stresses. The analysis will be extended to investigate the state of stress north to Alaska, and south to include the Rivera Triple Junction. The area of analysis will include the effects of GPE differences out to the Mid-Atlantic Ridge. A coupled analysis will investigate the self-consistent kinematics using observations from GPS, VLBI, SLR, and Quaternary fault slip rates. The proposed joint kinematic and dynamic modeling is important because it provides a comprehensive understanding of the relationship between geodetic observations (GPS, VLBI, SLR), lithospheric strain rates, and lithospheric stress. Refined models of the dynamics will be investigated using forward modeling methods with velocity boundary conditions determined from the kinematic modeling. They will also investigate the possible role of basal tractions in affecting the dynamics. This work should provide important input to enhance the planning and implementation of the proposed Plate Boundary Observatory and USArray initiatives.