Mantle layering from ScS reverberations 1. Waveform inversion of zeroth-order reverberations

This is the first paper in a four-part sequence that examines the nature of mantle layering required by the multiple-ScS phases and internal reflections observed within the reverberative interval of SH-polarized seismograms. Here we present path-averaged estimates of the two-way travel times through the crust+mantle (τ_ScS) and crust alone (τ_M), the whole mantle quality factor (Q_ScS), and the reflection coefficient at the M discontinuity (R₀(z_M)) obtained by iterative waveform inversion of ScS reverberations. We show that Q_ScS estimates derived from direct waveform inversion can be biased significantly if reverberations originating within the crust are ignored, especially in continental regions where the crust is thick. -from Authors