The three-dimensional shear velocity structure of the mantle from the inversion of body, surface and higher-mode waveforms

Abstract

We present a 3-D model of shear heterogeneity (V sh ) in the whole mantle, derived from the inversion of hand-picked body, surface and higher-mode waveforms. The forward and inverse problems are formulated using the non-linear asymptotic coupling theory, the zeroth-order asymptotic expansion of a Born seismogram computed by normal mode summation and including coupling across mode branches. We invert iteratively for mantle heterogeneity and for centroid moment tensors until convergence. Our model, SAW24B16, is parametrized laterally in spherical harmonics up to degree 24 and radially in 16 cubic b-splines with knots spaced to reect the data sampling with depth.