Azimuthal Anisotropy From Multimode Waveform Modeling Reveals Layering Within the Antarctica Craton ...

• Main Authors: Beghein, Caroline, Xu, Haotian
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Zenodo 2023
• Subjects: Antarctica, seismic anisotropy, seismic tomography, surface waves; Antarc*; Antarctica
• Online Access: https://dx.doi.org/10.5281/zenodo.8346552; https://zenodo.org/record/8346552

The isotropic structure of the crust and upper mantle under Antarctica has been constrained by many studies. However, the depth dependence of seismic anisotropy, a powerful tool to characterize deformation and flow, is still poorly known. Here, we modeled three-dimensional (3-D) variations in azimuthal anisotropy under Antarctica using a multimode Rayleigh waveform fitting technique. We first searched the model space with a reversible-jump Markov Chain Monte Carlo approach to find path-averaged vertically polarized shear wave velocity profiles that fit fundamental and higher mode Rayleigh waveforms. We then inverted them to obtain a 3-D velocity and azimuthal anisotropy model across the region down to 600 km depth. Our results reveal that the east-west dichotomy found in other studies is not only characterized by different wave velocities but also by different anisotropy directions, likely reflecting the different deformation histories of the two blocks. Azimuthal anisotropy was found to be present in the ... : submitted to Seismica ...