EAGER: Vectorial Anisotropic Body and Surface Wave Tomography Using USArray Data

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Robust modeling of both strength and orientation of anisotropicstructure is a tantalizing tool for constraining the dynamic processes in the lithospheric andsub-lithospheric mantle beneath North America, directly meeting the Earthscope goals of understandingthe active deformation of North America and tying it to deep Earth structure anddynamics. The long term goal of this research is to develop more detailed regional and globalmodels of seismic anisotropy that can both illuminate the dynamic processes of the upper mantle,as well as allowing for direct comparison with geodynamically predicted models. Theobjective of this EAGER application, which is the next step towards this long-term goal, is todevelop a new approach to image dynamic processes in the lithospheric and sub-lithosphericmantle beneath North America with a novel technique combining both body wave and surfacewave observables that allows for finite-frequency vectorial tomography. The international collaborationproposed here is uniquely suited to bring these approaches the PI and the researchgroup of S´ebastien Chevrot have been working on together and take advantage of the incredibledataset offered by the USArray transportable array to move towards obtaining an unprecedentedmodel of anisotropic structure beneath North America. The project will develop these modelsby pursuing the following specific aims. 1) Perform synthetic testing of joint inversions usingthis new approach. The inversions will allow us to gain unprecedented information about bothstrength and orientation of anisotropy. 2) Assemble and process USArray shear splitting andsurface wave data and merge and improve existing software between the two research groups.Dense data coverage of both splitting intensity and multi-taper fundamental mode phase delaywill be possible, and since both approaches have been developed from a consistent elastic parameterization,merging the software and performing joint inversions of the data shows greatpotential for greatly improving the capabilities of anisotropic modeling.