Study of rock anelasticity for seismological application

最近的实验研究表明，多晶材料的滞弹性服从麦克斯韦频率（fm）标度：1/Q（fn），其中fn=f/fm。然而，由于实验室中的fn通常比地震波的fn低得多（6 < log_10（fn）< 9），因此这种比例对地震波的适用性还没有得到保证。通过使用多晶有机硅作为地幔岩石的模拟物，我们测量了直到log_10（fn）= 8的滞弹性，发现这种标度在log_10（fn）> 4时并不完全适用。进一步的研究表明，在不同温度、晶粒尺寸和化学成分下获得的弛豫谱可以由受麦克斯韦频率标度影响的背景和以log_10（fn）~ 3为中心的峰的叠加来表示。随着温度、漏极尺寸和杂质含量的增加，峰值幅度和宽度显著增加，导致麦克斯韦频率定标在log_10（fn）> 4时失效。

Recent experimental studies have shown that anelasticity of polycrystalline materials is subject to the Maxwell frequency (fm) scaling: 1/Q(fn) with fn=f/fm. However, the applicability of this scaling to the seismic waves has not been guaranteed because fn in the laboratory is usually much lower than that of the seismic waves (6 < log_10(fn) < 9). By using polycrystalline organic borneol as an analogue to mantle rock, we measured anelasticity up to log_10(fn) = 8 and found that this scaling is not fully applicable at log_10(fn) > 4. 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 subject to the Maxwell frequency scaling and a peak centered at log_10(fn) ~ 3. Significant increases of the peak amplitude and width with increasing temperature, drain size, and impurity content result in failure of the Maxwell frequency scaling at log_10(fn) > 4.