CSEDI: Collaborative Research: Toward a Comprehensive Model of Mantle Flow & Seismic Anisotropy in the Western US - Using Mineral Physics to Directly link Geodynamics & Seismology

University Of California-San Diego Scripps Inst Of Oceanography, La Jolla CA

Investigators

Abstract

Quantifying the relationship between seismic anisotropy and mantle flow is important for advancing our understanding of surface tectonics and convection in the Earth's mantle. The investigators propose a joint approach: to calculate regional geodynamic flow models, compare derived finite strain to mineral physics calculations of texture, and perform seismological modeling to find both strain and texture predictions for anisotropy that are compatible with observations. They strive to answer the following questions: How are strain, mantle flow, and anisotropy related, in orientation and in magnitude? To what degree are deep convective currents coupled to the lithosphere? Can results from laboratory deformation experiments be applied to the behavior of the mantle at much lower strain rates? The western United States are an ideal natural test-bed for this project since the density of seismic and geodetic data is one of the highest worldwide, allowing for good lateral and depth resolution, which will increase further during the Earthscope efforts. The proposed study will also be useful for planning the future deployment of seismic instrumentation, in particular within the western United States plate boundary region. Funding will provide support for two female PIs and for the career development of two junior researchers working on a self-directed project. At the end of the funding period, the PIs expect to provide the community with a real-world test of texture formation algorithms and strain-anisotropy relationships, and with a quantitative guide to the interpretation of seismological observations of anisotropy with respect to geodynamics.