TY - JOUR
AU - Yamauchi, Hatsuki
AB - Recent experimental studies have shown that anelasticity of polycrystalline materials is subject to the Maxwell frequency (fM) scaling: Q−1(f/fM). However, the applicability of this scaling to the seismic waves has not been guaranteed because experimental frequencies normalized to fM of the laboratory samples are usually much lower than the seismic frequencies normalized to fM in the upper mantle (106≤f/fM≤109). In this study, by using polycrystalline organic borneol as an analogue to mantle rock, we measured anelasticity up to f/fM≃108 and found that the Maxwell frequency scaling is not fully applicable at f/fM>104. A closer examination showed that each of the relaxation spectra obtained under various temperature, grain size, and chemical composition can be represented by the superposition of a background dissipation subject to the Maxwell frequency scaling and a peak dissipation centered at f/fM≃103. Significant increases of the peak amplitude and width with increasing temperature, grain size, and impurity content result in failure of the Maxwell frequency scaling at f/fM>104, where the peak dissipation dominates over the background dissipation. The peak is significantly broadened near the solidus temperature (T/Tmelt=0.93), producing an absorption band toward the normalized seismic frequencies. The absorption band suggested by the present data is characterized by variable amplitude and width, indicating a nonlinear reduction of seismic velocity near the solidus.
TI - Temperature, grain size, and chemical controls on polycrystal anelasticity over a broad frequency range extending into the seismic range
JF - Journal of Geophysical Research: Solid Earth
DO - 10.1002/2014JB011146
DA - 2014-01-01
UR - https://www.deepdyve.com/lp/wiley/temperature-grain-size-and-chemical-controls-on-polycrystal-9bXWjMe3gU
SP - 5414
EP - 5443
VL - 119
IS - 7
DP - DeepDyve
ER -