Origin of the low rigidity of the Earth's inner core
Origin of the low rigidity of the Earth's inner core
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DOI：
10.1126/science.1141374
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发表时间：
2007-06-15
期刊：
影响因子：
56.9
通讯作者：
Johansson, Boerje
中科院分区：
文献类型：
--
作者：
Belonoshko, Anatoly B.;Skorodumova, Natalia V.;Johansson, Boerje
地球的固体铁内核具有低刚性，这表现在与铁合金中测量的剪切波速度相比，剪切波速度非常低。通常，当估计多晶体的弹性性质时，计算单晶的不同取向的平均值。这种方法没有考虑在与内核条件相关的高温下可能大量存在的晶界和缺陷。通过使用分子动力学模拟，我们表明，如果缺陷被认为是，计算的剪切模量和剪切波速度显着降低相比，从平均单晶值获得的那些估计。从而解释了内核中低剪切波速度的原因。
Earth's solid-iron inner core has a low rigidity that manifests itself in the anomalously low velocities of shear waves as compared to shear wave velocities measured in iron alloys. Normally, when estimating the elastic properties of a polycrystal, one calculates an average over different orientations of a single crystal. This approach does not take into account the grain boundaries and defects that are likely to be abundant at high temperatures relevant for the inner core conditions. By using molecular dynamics simulations, we show that, if defects are considered, the calculated shear modulus and shear wave velocity decrease dramatically as compared to those estimates obtained from the averaged single-crystal values. Thus, the low shear wave velocity in the inner core is explained.