Seismological Investigations of Deep Earth Structure

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EAR-0229323Peter M. ShearerThe increasing availability of large numbers of high-quality digital records from the global seismic networks has made possible a variety of new ways to study deep Earth structure. By analyzing hundreds or thousands of seismograms, it is often possible to resolve new features in the data, or to perform more comprehensive analyses of problems that were previously addressed on smaller scales. This project will continue and extend analyses of global seismic data at U.C. San Diego to address a variety of geophysical issues. These include: (1) Resolution of seismic discontinuities in the upper mantle using reflected and converted seismic phases, (2) Integrated inversions for discontinuity topography and three-dimensional seismic velocity variations in the mantle, (3) Analyses of both compressional and shear waves to resolve details of mantle attenuation structure, (4) A search for hypothesized mid-mantle discontinuities that may separate the mantle into different convecting cells, (5) Study and modeling of high-frequency waves scattered from small-scale mantle structure, and (6) Development and application of waveform cross-correlation and cluster analysis techniques to long-period waveforms. This research is likely to lead to improved methods for seismic data analysis and new constraints on deep Earth structure, composition and evolution. The bulk of the funding will provide graduate student and postdoc support that will further education in the Earth Sciences.