Effect of tides and source location on nearshore tsunami-induced currents
Effect of tides and source location on nearshore tsunami-induced currents
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DOI：
10.1002/2016jc012435
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发表时间：
2016-12-01
影响因子：
3.6
通讯作者：
Lynett, Patrick J.
中科院分区：
文献类型：
--
作者：
Ayca, Aykut;Lynett, Patrick J.
在这里，我们提出了数值模拟研究的结果，该研究研究了事件最大海啸诱发的电流如何因潮汐和波浪方向性的动态效应而变化。首先，通过将海啸与潮汐耦合并允许初始海啸波到达各个潮汐阶段，对三个港口的潮汐-海啸相互作用进行了分析。我们发现，对于所研究的事件和港口，海啸-潮汐相互作用可以使港口经历的事件最大水流速度改变高达 25%，并且我们注意到这种影响具有高度的地点特异性。其次，为了评估波浪方向性对事件最大洋流的影响，将地震源放置在整个太平洋地区，并调整震级以在研究港口产生相同的最大近海岸振幅。我们的分析还表明，对于所检查的港口和来源，离岸方向性和海啸频率内容的影响对港口中经历的事件最大电流的影响较弱。事件最大海流更重要的依赖性是波浪的近港振幅，这表明仅用有关预测的当地最大海啸振幅的信息就可以相当好地预测由远场大地震产生的海啸引起的港口中的事件最大海流。这项研究的动机是希望为了解潮汐和波浪方向性对沿海地区基于海流的海啸灾害的动态影响奠定基础。在海啸流建模中，考虑这些方面至关重要，但也具有挑战性。
Here we present the results of a numerical modeling study that investigates how event-maximum tsunami-induced currents vary due to the dynamic effects of tides and wave directivity. First, analyses of tide-tsunami interaction are presented in three harbors by coupling the tsunami with the tide, and allowing the initial tsunami wave to arrive at various tidal phases. We find that tsunami-tide interaction can change the event-maximum current speed experienced in a harbor by up to 25% for the events and harbors studied, and we note that this effect is highly site-specific. Second, to evaluate the effect of wave directionality on event-maximum currents, earthquakes sources were placed throughout the Pacific, with magnitudes tuned to create the same maximum near-coast amplitude at the harbor of study. Our analysis also shows that, for the harbor and sources examined, the effect of offshore directionality and tsunami frequency content has a weak effect on the event-maximum currents experienced in the harbor. The more important dependency of event-maximum currents is the near-harbor amplitude of the wave, indicating that event-maximum currents in a harbor from a tsunami generated by a large far-field earthquake may be reasonably well predicted with only information about the predicted local maximum tsunami amplitude. This study was motivated by the hope of constructing a basis for understanding the dynamic effects of tides and wave directivity on current-based tsunami hazards in a coastal zone. The consideration of these aspects is crucial and yet challenging in the modeling of tsunami currents.