The flexural creep responses of a Co-Mg olivine-plus-basalt aggregate at temperatures near 1100 ¿C have been transformed to give attenuation spectra (QE-1 vs. &ohgr;) as functions of temperature. The experimental creep response of this mantle-analog material is well-modeled as a Burgers solid, displaying a steady-state creep that is preceded by a transient deceleration. Calculated attenuation spectra are based on the Burgers solid viscosities and elastic constants obtained from the creep experiments. The attenuation becomes total and zero in the low- and high-frequency limits, respectively, as is appropriate for polycrystalline olivine having a diffusional creep rheology. At intermediate frequencies (10-4 Hz to 10-2 Hz), Q-1E experiences a local maximum. Both the magnitude (QE-1≈15) and central frequency of this loss maximum increase with temperature. The attenuation peak is an anelastic loss compatible with the transient creep response; it is inferred to represent a melt flow mechanism that adjusts the size of melt-bearing triple-grain junctions in response to changes in the stress state. ¿ American Geophysical Union 1990