Collaborative Research: Seismological and Geodynamic Investigation of Mantle Anisotropy

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This project will evaluate the robustness, resolution, and required complexity of global seismologic and geodynamic models of upper mantle azimuthal anisotropy in order to improve our understanding of mantle dynamics. Recent years have seen a refinement of seismological models of anisotropy, presumably indicative of shearing in mantle flow. Particularly surface wave inversions have been linked to models of mantle circulation with some success. Such findings make it appear feasible to test hypotheses for regional tectonic models using sophisticated synthetic data sets in the near future. However, while several questions about the implications of anisotropy remain unanswered, it is also true that comprehensive and quantitative models with thorough estimates of uncertainties are still lacking. This project addresses some of the relevant issues of seismological analysis and improved geodynamic models, such as: How stable are azimuthal anisotropy patterns with respect to data selection and inversion methods? How well constrained is anisotropy under continents and oceanic regions? What are the characteristic to convection models, from Newtonian to power-law rheology, from laterally constant to varying viscosity, and from finite strain to texture modeling. A range of resolution and synthetic model tests will be performed to evaluate the robustness of the seismological models. Such a combined seismologic and geodynamic research program will lead to new insights into upper mantle structure, anisotropy formation, and mantle convection. The aim is to formalize our understanding of lithospheric and upper mantle deformation based on mantle flow, in order to develop models with specific regional predictions that are useful for the design of field campaigns and geologic hypothesis testing.