Research in Tsunami Generation and Propagation

要求为控制远场，即跨洋海啸产生和传播的地震学参数性质的基础研究工作提供资金。具体地说，我们计划开展以下研究：(I)开发一种基于在很长但可变的周期内测量瑞利波的地幔震级mm，以便实现对远震地震的地震矩的实时单站测量，从而为可能发布海啸警报提供足够的信息；(2)系统研究一些震源参数，如震源深度、震源机制几何形状、破裂几何形状等对震源激发海啸的影响；我们将主要关注地壳结构的影响，特别是沉积分层的存在，以及非双重来源的影响，例如那些涉及滑坡和火山过程的来源；(3)使用详细的破裂模型来合成个别地震的海啸，包括所谓的“海啸地震”，其海啸比根据其地震矩预测的海啸大10倍；(4)研究海洋深度的变化由于海啸速度的横向不均匀而造成的聚焦和散焦效应，从而使海啸射线折射。拟议的研究是对在海啸产生时以及在其传播过程中、启动前和共振效应对潮汐观测站测量的海啸幅度的最终贡献的控制因素的广泛尝试。

Funding is requested for a fundamental research effort in the nature of seismological parameters controlling generation and propagation of far-field, i.e., transoceanic tsunamis. Specifically, we plan to carry out the following research: (i) develop a mantle magnitude Mm based on the measurement of Rayleigh waves at the very long but variable periods, in order to make feasible the one-station measurement of the seismic moment of a teleseismic earthquake in real time thereby providing adequate information for the possible issuance of tsunami warnings; (ii) research systematically the influence of a number of source parameters such as depth of focus, geometry of focal mechanism, geometry of rupture, etc., on the excitation of tsunamis by earthquake sources; we will focus primarily on the influence of crustal structure, and in particular of the presence of sedimentary layering, as well as on the effect of non-double- couple sources such as those involved in landslides and volcanic processes; (iii) use detailed rupture models to synthetize the tsunamis of individual earthquakes, including the so-called "tsunami earthquakes", whose tsunamis as much as 10 times greater than predicted from their seismic moments; and (iv) research the focusing and defocusing effects that variations in oceanic depth creates through lateral heterogeneity in tsunami velocities, and consequently refraction of tsunami rays. The proposed research constitutes a broad attempt at understanding the factors controlling the amplitude of the tsunami at its generation, and during its propagation, before run-up and resonance effects ass their final contribution to the amplitude measured at a tidal gauge station.