2011 Articles

Anelasticity and viscosity of partially molten rock analogue: Toward seismic detection of small quantities of melt

McCarthy, Christine; Takei, Yasuko

Anelasticity and diffusion creep viscosity of partially molten rock analogue were measured experimentally at various melt fractions (0.0025–0.04). The presence of even a small quantity of melt phase causes a significant increase in attenuation and dispersion, and decrease in viscosity (melt effect). Similar changes are additionally caused by the presence of a secondary solid component (chemical effect). The similitude that was observed in the anelasticity of melt-free systems when scaled by the Maxwell frequency for temperature and grain size effects was observed, too, in that of melt-bearing systems when scaled by the Maxwell frequency for melt and chemical effects. The combined melt and chemical effects on anelasticity offer a potential means of identifying small quantities of melt with seismic velocity perturbations.