Research in Seismic Phenomena Connected with Earthquakes and Explosions

摘要

The structure of the crust and upper mantle in the Western United States has been intensively studied by refraction and reflection techniques. Strong lateral variations have been found which correlate well with gravity, heat flow, P-delay, and other geophysical data. Methods have been developed to handle lateral variations both for body wave and surface wave studies. A method has been developed for analyzing high pressure shock wave data in order to make direct comparisons with seismic data. The lower mantle is clearly enriched in iron compared to the upper mantle. The low-velocity zone has been determined to be caused by partial melting. Free oscillation data have been inverted to obtain continental and oceanic Earth models. Theoretical work for wave propagation in inhomogeneous media has provided a number of results in diffraction theory which are important in determining the nature of the Earth's core mantle boundary.