Continental Dynamics of Asia

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Holt 9909621 The investigators propose to quantify the large-scale driving forces influencing active deformation in Asia. They will use observations of Quaternary Fault slip rates, Global Positioning System (GPS) velocities, topography data, and geoid (gravity) data to quantify the magnitude and style of strain rates and stresses within all areas influenced by the India-Eurasia continental collision. This work is designed to integrate both modeling and observations on a large scale, in which case distances between GPS stations are of the order of the thickness of the crust or the entire lithosphere. Much of the GPS data will be supplied (in vector form) by colleagues in China. Although the investigators will use available GPS velocity vectors to help constrain dynamic models, one objective in this research is to identify regions where future geodetic observations (or refined measurements at existing sites) are needed in order to test alternative tectonic hypotheses. The investigators will use a new methodology in which the stress field contributions associated with density differences within the lithosphere (near-field) and tectonic plate interaction (far-field) are quantified separately. This method should thus lead to new understanding about the relative role of collision-induced stresses and stresses that result from topography. The quantification of strain accumulation and the state of stress will be useful in seismic hazard analysis. Furthermore, the investigation of continental dynamics within Asia will yield insight into the nature of the dynamics affecting the Pacific-North American plate boundary zone in the United States.