HR: 1340h
AN: S23B-1372    [Abstracts]
TI: Surface Wave Tomography for Geodynamically Relevant Anisotropic Models
AU: * Panning, M P
EM: mpanning@princeton.edu
AF: Dept. of Geosciences Princeton University, 318 Guyot Hall, Princeton, NJ 08544, United States
AU: Nolet, G
EM: nolet@princeton.edu
AF: Dept. of Geosciences Princeton University, 318 Guyot Hall, Princeton, NJ 08544, United States
AB: Using seismic data to constrain not only the strength of anisotropy, but the orientation of the best-fitting symmetry axis is important for geodynamic understanding, as this can be ideally related to mantle convection flow patterns. Many recent surface wave models, though, only deal with anisotropy with a vertical axis of symmetry. On the other hand, anisotropic shear velocity models based on body wave measurements such as SKS splitting have traditionally assumed a horizontal axis of symmetry for the material properties, as a purely vertical axis produces negligible shear wave splitting. Recently, however, methods have been developed for using splitting measurements in tomographic inversions for more general symmetry axis orientations (e.g. Chevrot, 2006; Abt and Fischer, 2007). There have also been surface wave studies which model azimuthal dependence of Rayleigh wave velocity through linearized dependence on a horizontal fast axis (e.g Montagner and Tanimoto, 1991; Simons et al, 2002). As the frequency content of body wave splitting measurements and surface wave observations differ greatly, it is essential to have an appropriate finite frequency theory in order to include both in a consistent framework. We derive here nonlinear expressions for 3D finite-frequency surface wave sensitivity to arbitrarily oriented hexagonal symmetric media. We also discuss practical means of inverting for such a model, including combination with the compatible approach of shear wave splitting tomography proposed by Chevrot (2006).
DE: 7255 Surface waves and free oscillations
DE: 7260 Theory
DE: 7270 Tomography (6982, 8180)
SC: Seismology [S]
MN: 2007 Fall Meeting