9628401 Ammon This research involves the combination of receiver-function and surface-wave information into the construction of a mutually consistent Earth-structure model of the crust and upper mantle. Both receiver functions and surface waves are sensitive to the shear velocity of the Earth but the information contained in these waveforms is complementary. Receiver functions are predominantly sensitive to the velocity contrasts, the surface waves are predominantly sensitive to slowly-varying velocity changes. Combining this complementary information should produce better images of the subsurface variations in shear velocity. Work will begin in North America. The results will help to understand the interaction between the curst and mantle during the evolution of the continents. ***