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。主要目标是定义特征（“可观察到的”），这些特征可以用来区分地震或滑坡是海啸的起源。在近场中，采用水动力模拟来检验各种源参数对附近海滩上的预期最大爬升和沿海滩的横向分布的影响。该策略是识别可观测值的组合，这些组合对于一种类型的源在很大程度上是不变的，因此可以作为源判别符。此外，这一办法将适用于在过去十年进行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。这项研究将使人们更好地了解震源参数（两种类型的震源）与附近海滩产生的累积之间的关系，并将改进用于估计和减轻未来区域范围内海啸影响的模型。在远场，该项目考虑了频率频散及其在各种震源情景下对海啸波形演变的影响，同样包括地震和滑坡。用色散码和非色散码进行的模拟比较应该找出那些可能增强远场色散效应的源条件，并将先前一维传播的结果推广到全二维海洋。本文将系统地讨论震源类型对指向性的影响。这对于震源来说是很容易理解的，但是对于滑坡来说仍然存在争议。本研究将建立远场滑坡源对海啸灾害的可能贡献，并澄清水动力理论中各种近似在许多源情景下的适用性问题。研究结果将应用于1946年阿留申地震的案例，该地震给美国造成了100年来最严重的海啸破坏，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，这些海啸的来源机制没有确切的描述。这项研究将大大提高预测未来海啸期间的洪水和溃坝的能力，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，并积极与新闻媒体互动。他们还将编纂和永久存档以前海啸实地调查期间获得的大型访谈录像数据集。

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.