Global Attenuation Model of the Whole Mantle Using Waveform Tomography

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9706380 Romanowicz This research is to resolve lateral variations in attenuation in the earth's mantle, which can help improve our understanding of the character of upwellings in the general mantle circulation. In recent work, a 3D model of shear attenuation in the upper mantle was developed, based on fundamental mode surface wave data in the spectral domain. The lateral resolution in this model is equivalent to that of a degree 6 spherical harmonics expansion. A new formalism developed for waveform inversion of surface wave and body wave seismograms was applied to obtain a degree 12 SH velocity model of the whole mantle. This work involves extending the waveform formalism to include off- great-circle path propagation and inverting for anelastic structure in the time domain. This will allow a deeper probing into the mantle using body wave information and eventually increase the lateral resolution of the Q models. ***