HR: 11:05h
AN: S32A-04    [Abstracts]
TI: Towards Multi-mode Diffractional Tomography in Radially Anisotropic Media
AU: * ZHOU, Y
EM: yingz@vt.edu
AF: Virginia Tech, Department of Geosciences MC 0420, Blacksburg, VA 24061, United States
AB: We calculate the three-dimensional (3-D) sensitivities of low-order, multi-mode, surface-wave phase and amplitude measurements to the Earth's lateral heterogeneity in seismic velocity as well as radial anisotropy. The 3-D Born scattering sensitivity kernels are formulated for multi-mode measurements made between the data and mode-summed synthetic seismograms using a surface-wave mode-summation approach that fully accounts for interactions between simultaneous overtone arrivals. We derive sensitivity kernels for cross-spectral multi-taper measurements in radially anisotropic reference earth models. Our calculations of sensitivity kernels show that (1) in the presence of radial anisotropy, SH and SV waves are strongly coupled, and the sensitivities of Rayleigh waves to P wave velocities (PH and PV) become significant, when higher-mode surface-wave energy dominates in the measurement window; and (2) the windowing/tapering processes applied in making measurements have strong effects on the sensitivity kernels, especially for measurements made with short time windows. In general, multi-taper measurements are less sensitive to window selections compared to single-taper (e.g., cosine-taper or boxcar-taper) measurements. This multi-mode surface-wave approach opens the opportunity for imaging high-resolution structure of seismic velocity and radial anisotropy in the top 1000 km of the mantle.
DE: 7208 Mantle (1212, 1213, 8124)
DE: 7255 Surface waves and free oscillations
DE: 7260 Theory
DE: 7290 Computational seismology
SC: Seismology [S]
MN: 2007 Fall Meeting