RESEARCH IN SEISMIC PHENOMENA CONNECTED WITH EARTHQUAKES AND EXPLOSIONS
Annual rept. 31 Oct 1967-1 Nov 1968
CALIFORNIA INST OF TECH PASADENA SEISMOLOGICAL LAB
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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. 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. 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 Earths core mantle boundary. Studies of the static strains and tilts using appropriate source models in media with decoupling or soft zones indicate that the observations of large tilts accompanying some earthquakes may be the result of block decoupling phenomena in the western part of the Continent.
- Geology, Geochemistry and Mineralogy