An approximate equation for qPqP reflection coefficients is used in order to recover contrasts in weak anisotropy (WA) parameters of media surrounding an interface. The approximation fits, within the subcritical region, exact calculations of reflections at a weak-contrast interface separating two homogeneous, weakly anisotropic elastic media of arbitrary symmetry. Linear dependence of reflection amplitudes on contrasts in WA parameters is convenient property of this approximation. Hence, the singular value decomposition (SVD) technique is applied to recovering the contrasts, with numerical reflection data from an interface separating an upper isotropic halfspace from a bottom transversely isotropic halfspace with horizontal axis of symmetry (HTI). Reflection amplitudes from a range of incidence angles commonly found in practice and from at least five measurement profiles are needed for recovering the contrasts in WA parameters. Such a conclusion is drawn by performing an uncertainty analysis for the inversion.
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