Collaborative Research: Generation Mechanisms of Near-and-Far Field Tsunamis

这一行动是为了支持一个合作研究项目，以研究地震或水下滑坡引起的海啸在近场和远场的产生和传播。 其主要目标是定义特征（“可观测”），可用于区分地震或滑坡作为海啸的起源。在近场，水动力学模拟被用来研究的影响，各种源参数的预期最大爬高附近的海滩，并沿着海滩的横向分布。 该策略是确定组合的观测量，将在很大程度上是不变的一种类型的源，因此可以作为源判别。 此外，这一方法将应用于过去十年海啸后调查期间收集的现有数据库，以便详细确定控制破坏程度和范围的震源机制。 这项研究将导致更好地了解源参数之间的关联（两种类型的来源）和在附近海滩上产生的上升，并将改进用于估计和减轻未来海啸在区域范围内的影响的模型。在远场，该项目考虑了频率分散及其对各种来源情况下海啸波形演变的影响，也包括地震和山体滑坡。 比较与色散和非色散代码进行的模拟，应确定这些源条件，可能会提高在远场的色散的影响，并概括为一个完整的二维海洋一维传播获得的早期结果。 将系统地讨论源类型对方向性的影响。 这对于地震源来说是很好理解的，但对于山体滑坡来说仍然存在争议。 这项研究将建立可能的贡献滑坡源的海啸灾害在远场，并澄清的问题，在流体动力学理论的各种近似下的一些源的情况下的适用性。 研究结果将应用于1946年阿留申地震的情况，这是过去100年来海啸对美国造成的最大破坏，但其确切的生成机制仍然难以捉摸。 还将对一些历史上的海啸进行研究，因为这些海啸没有确切的来源机制，这项研究将大大提高预测未来海啸期间淹没和上升的能力，从而减轻其影响。 主要研究人员将继续他们的传统，研究生和本科生参与研究的各个方面，并与新闻媒体积极互动。 他们还将汇编和永久存档以前海啸实地调查期间获得的大量录像访谈数据集。

This action is to support a collaborative research project to study the generation and propagation of tsunamis in both the near and far fields, as generated by earthquakes or underwater landslides. The principal goal is to define features ("observables") that can be used to discriminate between an earthquake or a landslide as the origin of a tsunami.In the near field, hydrodynamic simulations are used to examine the influence of various source parameters on the expected maximum runup on a nearby beach, and on the lateral distribution along the beach. The strategy is to identify combinations of observables that would be largely invariant for one type of source, and thus could serve as source discriminants. In addition, this approach will be applied to the existing databases collected during the post- tsunami surveys conducted in the past decade, in order to determine in detail the source mechanisms that controlled the amplitude and extent of devastation. This research will result in a better understanding of the association between source parameters (for both types of sources) and the resulting runup at nearby beaches, and will improve the models used in estimating and mitigating the impact of future tsunamis on a regional scale.In the far field, the project considers the frequency dispersion and its effect on the evolution of tsunami waveshapes under a variety of source scenarios, again including both earthquakes and landslides. Comparing simulations performed with dispersive and non-dispersive codes should identify those source conditions that may enhance the effect of dispersion in the far field, and generalize to a full two-dimensional ocean earlier results obtained for one-dimensional propagation. The influence of source type on directivity will be addressed systematically. This is well understood for earthquake sources, but remains debatable for landslides. This research will establish the possible contribution of landslide sources to tsunami hazard in the far field, and clarify the question of the suitability of various approximations in hydrodynamic theories under a number of source scenarios. The results will be applied to the case of the 1946 Aleutian earthquake, which inflicted the greatest devastation by a tsunami on the United States in the past 100 years, but whose exact generating mechanism is still elusive. A number of historical tsunamis will also be studies, for which no exact description of source mechanism is available.The research will significantly improve the capability to predict inundation and runup during future tsunamis, and thus for mitigation of their effects. The principal investigators will continue their tradition of graduate and undergraduate student involvement in all aspects of the research, and active interaction with the news media. They will also compile and permanently archive the large dataset of videotaped interviews obtained during previous tsunami field surveys.