Properties of electromagnetic fields generated by tsunami first arrivals: Classification based on the ocean depth
Properties of electromagnetic fields generated by tsunami first arrivals: Classification based on the ocean depth
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DOI：
10.1002/2015gl063055
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发表时间：
2015-04-16
影响因子：
5.2
通讯作者：
Tyler, Robert H.
中科院分区：
文献类型：
--
作者：
Minami, Takuto;Toh, Hiroaki;Tyler, Robert H.
海啸流与地磁场耦合产生电流和相关的磁场。虽然电磁（EM）海啸信号可用于分析，甚至预测海啸的传播，变浅水深的流体+电动力学的动态自洽效应还没有得到充分的澄清。在这项研究中，我们将海啸电磁现象分为三种情况下，海洋深度的基础上，发现更深的海洋的结果在更强的自感应，由于海啸相速度和海洋电导的增加。在这种深海的情况下，相对于海面高程的垂直磁变化的相位超前较小，而在海啸到来之前，水平磁分量的初始上升变得可观察到。此外，我们证实，在较浅的海洋海啸高度的增强移动的海洋深度提供海啸磁场的最大振幅从约2.0公里到1.5公里。
Tsunami flow coupled with the geomagnetic field generates electric currents and associated magnetic fields. Although electromagnetic (EM) tsunami signals can be used for analysis and even forecasting tsunami propagation, the dynamically self-consistent effect of shoaling water depth on the fluid + electrodynamics has not been adequately clarified. In this study, we classify tsunami EM phenomena into three cases based on the ocean depth and find that the deeper ocean results in stronger self-induction due to the increase in both tsunami phase velocity and ocean conductance. In this deep-ocean case, the phase lead of the vertical magnetic variation relative to the sea surface elevation is smaller, while an initial rise in the horizontal magnetic component becomes observable prior to tsunami arrival. Furthermore, we confirm that the enhancement of tsunami height in shallower oceans shifts the ocean depth supplying maximum amplitudes of tsunami magnetic fields from approximately 2.0km to 1.5km.