A Bayesian approach to anisotropic surface wave tomography

1D Anisotropic Surface Wave Tomography with Bayesian Inference

Anisotropic surface wave tomography is treated as an optimisation problem where it proceeds through a linearised two-step approach.It involves the construction of 2d group or phase velocity maps for eachconsidered period, followed by the inversion of local dispersion curves inferred from these maps for 1d depth-functions of the elastic parameters.Here, we cast the second step into a fully bayesian probability framework.Solutions to the inverse problem are thus an ensemble of model parameters distributed according to a posterior probability density function and their corresponding uncertainty limits.The method is applied to azimuthally-varying synthetic surface wave dispersioncurves generated by a 3d-deforming upper mantle.We show that such a procedure captures essential features of the upper mantle structure.The robustness of these features however strongly depends on the wavelength of the wavefield considered and the choice of the model parameterisation.Additional information should therefore be incorporated to regularise the problem such as the inclusion of petrological constraints to match the geodynamic predictions.