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Gao et al. 1993
Gao, L.S., Poirier, J.P. and Aki, K. (1993). Attenuation due to partial melting: An experimental study on a model system, using the Lab Coda method. Journal of Geophysical Research 98: doi: 10.1029/92JB02296. issn: 0148-0227.

Partial melting at the grain boundaries of mantle rock is a source of attenuation often invoked in the interpretation of teleseismic data. However, related experimental studies are extremely difficult and hence are scarce. We have used a convenient metallurgical system to model a rock sample with a layer of fluid at grain boundaries: the analog of the rock sample is a cylinder of fine-grained, pure aluminum (diameter is 6 cm; height is 6 cm), and the analog of the fluid is provided by a thin layer of aluminum-gallium eutectic at the grain boundaries. The metal gallium, liquid at room temperature, diffuses extremely rapidly into the grain boundaries of aluminum where it forms a soft eutectic that melts at 28 ¿C. The total amount of gallium in the sample represents about 0.2 wt %. Ultrasonic (1 MHz) pulses were transmitted through the sample by a transducer, and the full waveform of the reflected and scattered signals, including the coda, were recorded. Analyses of the decay parameter of the coda envelope yield values of Q-1. Preliminary results shown that the thin film of aluminum-gallium eutectic at the grain boundaries noticeably increases attenuation. For pure aluminum at room temperature, Q-1 =0.095¿10-3; after invasion of gallium into the grain boundaries, the value measured at 26 ¿C (in solid state) was Q-1=0.62¿10-3; at 28 ¿C, when the eutectic became liquid, Q-1=1.01¿10-3, an order of magnitude higher than for pure aluminum. ¿ American Geophysical Union 1993

BACKGROUND DATA FILES

Abstract

Keywords
Physical Properties of Rocks, Wave attenuation, Volcanology, Physics and chemistry of magma bodies, Tectonophysics, Physics of magma and magma bodies
Journal
Journal of Geophysical Research
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Publisher
American Geophysical Union
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