This research is a study of lithospheric strength and tectonics by continued tomographic studies of lateral variations in Pn velocity and crustal thickness. The goals include tomographic mapping of Pn velocity and crustal thickness; modelling the effects of complex crust and mantle structure on Pn travel times; and interpreting the results in light of regional tectonics. Past work has mapped Pn in the Middle East, Central Asia, and the western United States. This work will extend that mapping into Europe and into Indochina. The data bases consist of ISC travel time data and travel times that are determined in this project. Ultimately, the quantitative knowledge of uppermost mantle velocity, crustal thickness, and other geophysical parameters will be used to link the tectonics and geology seen at the surface of the earth to the mantle beneath in order to gain insight into the processes that shape the earth's surface.
