Effects of Partial Melting on Seismic Velocity and Attenuation: A New Insight from Experiments
Effects of Partial Melting on Seismic Velocity and Attenuation: A New Insight from Experiments
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DOI：
10.1146/annurev-earth-063016-015820
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发表时间：
2017-09
影响因子：
14.9
通讯作者：
Y. Takei
中科院分区：
文献类型：
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作者：
Y. Takei
长期以来，部分熔融对地震速度和衰减的影响一直被研究，主要集中在熔融的直接影响上，如孔洞弹性效应。对于非常小的熔体分数，直接影响通常很小。由于地球化学研究表明，部分熔融过程中的熔体分数很小(∼为0.1%)，因此很难用熔体的直接作用来解释上地幔低速区。最近的实验研究，通过使用一种类似的岩石，捕捉到了在没有熔化的情况下，在部分熔化之前多晶体滞弹性的显著增强。这一新认识的效应使我们能够一致地解释地震学和地球化学观测结果。新的滞弹性模型显著改变了对上地幔地震结构的解释。本文从线性滞弹性的基本知识出发，综述了近年来对多晶体滞弹性的认识进展。
The effects of partial melting on seismic velocity and attenuation have long been studied by focusing on the direct effects of melt, such as the poroelastic effect. The direct effects are generally very small for a very small melt fraction. Because geochemical studies have shown that the melt fraction during partial melting is very small (∼0.1%), it is difficult to explain upper-mantle low-velocity regions by the direct effects of melt. Recent experimental studies, by using a rock analog, have captured a significant enhancement of polycrystal anelasticity just before partial melting in the absence of melt. This newly recognized effect enables us to interpret seismological and geochemical observations consistently. The new anelasticity model significantly changes the interpretation of upper-mantle seismic structures. This review summarizes the recent progress in the understanding of polycrystal anelasticity, starting from a basic knowledge of linear anelasticity.