This award will support collaborative research betwen Dr. Emile Okal, Department of Geological Sciences, Northwestern University and Professor Michael Cara, Institut de Physique du Globe, University of Louis Pasteur, Strasbourg, France. The research project will involve the joint operation of a three-component broad-band seismic station at Midway Island (Pacific Ocean) Both investigators have been engaged for several years in surface-wave studies on a world-wide basis, and locally in the Pacific Ocean. The common goal in this research has been the resolution of the crustal and upper mantle structure under the Pacific Basin, in particular, its lateral heterogeneity and anisotropy. In this general framework, Drs. Cara and Okal have started an active cooperation in surface-wave investigations in the Pacific Basin. In this project they will jointly operate a "portable" high quality broad-band seismic station in Midway Island. The data to be gathered will be of importance for our understanding of the mechanical and thermal evolution of the lithosphere near hot spots, as well as for the dynamics of the mantle plumes. A major difficulty in constraining models of thermal rejuvenation of the lithosphere is the lack of observational constraints, other than ocean bathymetry and heat flow. The results of this research will address this problem.
