Research in Tsunami Generation and Propagation

要求为控制远场即跨洋海啸的产生和传播的地震参数性质的基础研究工作提供经费。具体而言，我们计划开展以下研究：(1)基于长变周期瑞利波的测量，开发地幔震级Mm，使远震地震的地震矩单站实时测量成为可能，从而为可能的海啸预警提供充分的信息；系统地研究若干震源参数，如震源深度、震源机制的几何形状、破裂的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，以及非双偶源的影响，如涉及滑坡和火山作用的源；（iii）使用详细的破裂模型综合个别地震的海啸，包括所谓的“海啸地震”，其海啸比地震矩预测的海啸大10倍；（iv）研究海洋深度变化通过海啸速度的横向非均质性以及海啸射线的折射所造成的聚焦和散焦效应。拟议的研究是一项广泛的尝试，旨在了解在海啸产生和传播期间，在上升和共振效应最终对潮汐测量站测量的幅度作出贡献之前，控制海啸幅度的因素。

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.