Anisotropy and the Structural Geology of the Tectosphere

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9805206ParkThis research deals with the mapping of seismic anisotropy in the continental crust and upper mantle of the Earth. In both the crust and upper mantle, seismic anisotropy can arise from preferred mineral orientations and fine layering of contrasting rock types. In the crust, anisotropy from aligned cracks is also often present, especially in the upper few km. The strength of anisotropy, its distribution with depth, its relation to plate motion, and the relation between mantle and crustal deformation are pivotal for our understanding of the mechanisms of continental formation and Earth history. This work will combine two complementary body-wave techniques: shear-wave splitting, and P-SH conversions in the P-coda. Continents are the longest-lasting surface remnants of the plate-tectonic engine, and also the principal record of this engine's activity prior to the Mesozoic. By characterizing the patterns of seismic anisotropy in the continental regions of the Earth, this research will investigate the record of process dynamics.