This project will use the growing revolutionary data source from the global array of broad-band seismometers to derive detailed seismic velocities through the upper mantle of tectonically active areas. The analysis technique is one which has been successfully developed and applied in pioneering earlier studies by the investigators. The tectonically active areas of the western US and Asia will be the focus of this study. The precision velocity distribution will be used as a constraint to models of the driving forces of the distortion of the crust and upper mantle and, thus, the research is a contribution to the National Earthquake Hazard Reduction Program.
