Continuing Support for the Operation of the Los Angeles Strong Motion Array

这一行动是为了支持一个合作研究项目，研究地震或水下山体滑坡引起的海啸在近场和远场的产生和传播。主要目标是定义可用于区分地震或滑坡的特征(“可观测值”)作为海啸的起因。在近场中，水动力模拟被用来研究各种源参数对附近海滩上的预期最大抬升以及海滩上的横向分布的影响。策略是确定对于一种类型的源基本上不变的可观测的组合，从而可以作为源的判别式。此外，这一方法将适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幅度和程度的来源机制。这项研究将更好地了解震源参数(对于两种类型的震源)与附近海滩由此产生的上升之间的联系，并将改进用于估计和减轻未来海啸对区域规模的影响的模型。在远场，该项目考虑了各种震源情景下的频率分散及其对海啸波形演变的影响，同样包括地震和山体滑坡。用色散和非色散代码进行的比较模拟应该识别那些可能增强远场中色散效应的源条件，并将先前获得的一维传播的结果推广到全二维海洋。系统地讨论了震源类型对指向性的影响。对于震源来说，这是很好的理解，但对于山体滑坡来说，这仍然是有争议的。这项研究将确定滑坡震源对远场海啸灾害的可能贡献，并澄清流体力学理论中的各种近似在一些震源情景下的适用性问题。这一结果将应用于1946年阿留申地震的案例，这场地震给美国造成了过去100年来最大的海啸破坏，但其确切的产生机制仍然难以捉摸。一些历史上的海啸也将被研究，但没有准确的震源机制描述。这项研究将极大地提高预测未来海啸期间的淹没和抬高的能力，从而减轻其影响。主要研究人员将继续他们的传统，即研究生和本科生参与研究的所有方面，并与新闻媒体积极互动。他们还将汇编和永久存档在以前的海啸现场调查中获得的录像访谈的大型数据集。

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.