This award will provide supplementary support to enable Dr. Jonathan Lees of the University of California, Santa Barbara to conduct collaborative research with Dr. Yoshimitsu Okada for six months at the National Research Center for Disaster Prevention, Tsukuba, Japan. They will apply tomographic techniques developed by Dr. Lees to determine the 3-dimensional P-wave velocity structure beneath the Kanto-Tokai district of Japan, and hence to image the subterranean crustal and upper mantle structures. The method developed by Dr. Lees assesses the behavior of tens of thousands of earthquake ray paths to determine the composition of the material along the paths. By superimposing the many linear descript- ions of the subterranean environment, a 3-dimensional description can be determined. Application of the tomographic method to the large, high quality data sets that have been recorded by dense seismic networks in Japan over many years should lead to a vastly improved understanding of the geological structures and tectonics of the region.
