Direct Comparison of the Tsunami-Generated Magnetic Field With Sea Level Change for the 2009 Samoa and 2010 Chile Tsunamis
Direct Comparison of the Tsunami-Generated Magnetic Field With Sea Level Change for the 2009 Samoa and 2010 Chile Tsunamis
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DOI：
10.1029/2021jb022760
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发表时间：
2021-11-01
影响因子：
3.9
通讯作者：
Minami, Takuto
中科院分区：
文献类型：
--
作者：
Lin, Zhiheng;Toh, Hiroaki;Minami, Takuto
海啸引起的导电海水运动在背景地磁主场存在的情况下可以产生磁场。先前的研究发现，利用海啸产生的海底磁场，可以在海啸实际到达之前预测传播方向和波高。本研究使用2009年萨摩亚和2010年智利海啸的观测数据和三维模拟将海啸磁场和海啸海平面变化关联起来。海啸观测磁场与海啸海平面变化的直接比较显示，垂直方向的海啸磁场分量bz比海平面变化来得早。通过将观测结果与三维模拟相结合，还发现了观测到的水平海啸磁分量bh中的“初始上升”信号，其到达时间甚至早于bz。我们进一步研究的精度转换的海啸磁场的海平面变化，并发现，磁场派生海啸海平面是精确的，从差压计数据。然而，我们的模拟表明，现有的海啸源模型与我们的海啸磁力数据不兼容。因此，有必要包括磁场引起的海啸海平面变化，以改善这些源模型。
The motion of conductive seawater by tsunamis can generate magnetic fields in the presence of the background geomagnetic main field. Previous studies found that, using the tsunami-generated seafloor magnetic field, it is possible to predict the propagation direction and wave height prior to the actual arrivals of tsunamis. This study correlates the tsunami magnetic field and the tsunami sea level change using observed data and three-dimensional simulations of the 2009 Samoa and 2010 Chile tsunamis. Our direct comparison of the tsunami observed magnetic field and tsunami sea level change illustrate that the vertical tsunami magnetic component, bz, arrived earlier than the sea level change. The "initial rise" signal in the observed horizontal tsunami magnetic component, bh, which was arrived even earlier than bz also is found by combing the observation with the three-dimensional simulations. We further examine the precision of conversion of the tsunami magnetic field to the sea level change and find that the magnetic field derived tsunami sea levels are as precise as those obtained from differential pressure gauge data. However, our simulation shows that existing tsunami source models are incompatible with our tsunami magnetic data. Therefore, it is necessary to include magnetic field derived tsunami sea level changes to improve those source models.