Linearized inverse scattering of teleseismic waves for anisotropic crust and mantle structure: 2. Numerical examples and application to data from Canadian stations

The objective of this study is to characterize elastic properties, including anisotropy, at the base of the crust and uppermost mantle using the Moho P M s phase recorded in the teleseismic P coda at Canadian stations. We use linearized inverse scattering and singular value decomposition to identify those parameter combinations to which idealized teleseismic data sets are most sensitive. Five to seven independent parameter combinations are likely to be resolvable, one of which is sensitive to isotropy, whereas the remainder quantify different harmonic orders (1θ, 2θ, 3θ) of back azimuthal response. Aside from the isotropic component which is resolved only by P ‐ SV interactions, P ‐ SV and P ‐ SH conversions exhibit a redundant sensitivity to model parameters for uniform back‐azimuthal sampling. We use parameter combinations from the idealized, uniform back‐azimuthal data distribution to compare Moho anisotropy at 25 broadband stations on the Canadian landmass. The isotropic component dominates at all stations and corresponds to shear velocity contrasts ranging between 10 and 35%. Perturbations to anisotropic material property parameters are more modest, generally between 3 and 7% when consistent between SV and SH responses and in many cases suggest an anisotropic lower crust. Inconsistent responses may manifest contamination by lateral heterogeneity, upper crustal reverberations, or pervasive crustal anisotropy leading to shear wave splitting.