Constraints on Mantle Anelasticity from SLR Tidal Estimates

Satellite Laser Ranging (SLR) measurements of the Earth’s gravity field can be used to solve for solid Earth tides. We use those solutions to place constraints on anelasticity in the Earth’s mantle at periods of 12 hours and 18.6 years. The results imply that the anelastic parameter Q is smaller for those tides than for seismic waves. We interpret this as evidence that Q is frequency dependent. We find that the frequency dependence suggested by the SLR measurements is reasonably consistent with laboratory measurements, but inconsistent with seismic observations.

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