Anelasticity, and the resulting velocity dispersion, is required in the Earth to reconcile seismic observations spanning three decades in frequency [e.g. Montagner and Kennett, 1996) and to compare high-frequency laboratory measurements with low-frequency tomographic models [e.g. Romanowicz, 1990; Karato, 1994]. Observed seismic wave attenuation is well explained by frequency independent anelasticity, which led to the concept of the mantle response as a superposition of absorption peaks with roughly constant attenuation in the seismic band.
We have performed preliminary investigations of the frequency dependence of anelasticity using the tranverse component surface (T>80s) and body (T>32s) waveforms of Li and Romanowicz  as well as a compilation of published normal mode quality factors. We consider a power law dependence of attenuation, . In our preliminary investigation, we conclude:
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