Towards 3-d Fabric In The Continental Lithosphere and Asthenosphere: The Tien Shan

[1] As shown by previous observations of shear wave splitting of the SKS phase, the fast direction of azimuthal anisotropy beneath the Tien Shan tends to be aligned with the strike of the belt. This direction implies that the anisotropy is related to the current orogenesis. Now we describe an attempt to constrain the distribution of the anisotropy with depth by combining observations of SKS and P receiver functions. The data are inverted for the parameters of anisotropy with the aid of a genetic algorithm. The results of the joint inversion suggest that the actual distribution of anisotropy with depth can be more complicated than usually thought. The deformed mantle layer can be a few hundred kilometres thick. In the most reliable models fast direction of anisotropy in the shallow mantle is significantly different from that inferred from the observations of SKS. At some stations the data require anisotropy in the crust.