Integrating Three-Dimensional Earthquake Rupture Dynamics, Ocean Acoustic Waves and Tsunami: Effects of Inelastic Failure in the Accretionary Wedge

浅俯冲带（上10？15公里）在浅倾斜的板块界面上发生地震，并有效地产生海啸。然而，人们对地震破裂产生海啸的物理机制还不太了解。这项研究将把研究人员以前的地震破裂模型扩展到3D，并将这些模型与海洋声波和海啸模型相结合。地震破裂和海洋声波和海啸的完全耦合系统提供了理解这些地震和海啸生成的物理的主要理论手段。这些模型也可以用来提取有用的信号，可用于区分潜在的机制和海啸earlywarning.This建议解决的主要问题之一，在地震力学：物理学的异常破裂特征和海啸成因浅俯冲带。为什么这些地震能有效地产生海啸，但辐射出微弱的高频能量？是什么导致了缓慢的破裂速度和低的力矩比例辐射能量？海啸是由海沟附近的大的浅部滑动、楔体中的分布非弹性变形还是两者都有引起的？海洋声波能用于海啸预警吗？随时间变化的海底变形如何影响近场海啸？这一为期三年的研究项目将包括以下活动：㈠开发一种更新的拉格朗日有限元方法，以在二维和三维中将海啸和海洋声波与地震破裂完全耦合，并利用现有的欧拉方法对其进行验证。(ii)模拟有和没有非弹性楔破坏的沿走向破裂传播，并研究它们如何显著影响海啸和海洋声波。测试和提取可用于海啸预警的信号。(iii)开发典型海啸地震的动态破裂模型，并模拟区域/海啸距离的波形。检查海啸、高速率GPS和海啸数据的分辨率。

Shallow Subduction zones (upper 10 ? 15 km) host earthquakes on shallow-dipping plate interfaces and efficient in generating tsunami. The physics of tsunami generation from earthquake ruptures is, however, not well understood. This research will extend the researcher's previous earthquake rupture models to 3D and integrate these models with ocean acoustic waves and tsunami models. The fully coupled system of earthquake rupture and ocean acoustic waves and tsunamis provides the principal theoretical means for understanding the physics of these earthquakes and tsunami generation. These models can also be used extract useful signals that can be used in differentiating underlying mechanisms and tsunami early warning.This proposal addresses one of the major unsolved problems in earthquake mechanics: the physics of anomalous rupture characteristics and tsunamigenesis in the shallow subduction zone. Why can these earthquakes generate tsunami efficiently but radiate weak high-frequency energy? What gives rise to slow rupture velocity and low moment-scaled radiated energy? Is tsunami generated by large shallow slip near the trench, distributed inelastic deformation in the wedge, or both? Can ocean acoustic waves be used in tsunami early warning? How does time-dependent seafloor deformation affect near-field tsunami? This 3-year research project will include the following activities: (i) Develop an updated Lagrangian finite-element approach to fully couple tsunami and ocean acoustic waves with earthquake rupture in 2D and 3D, and validate it with an existing Eulerian approach. (ii) Simulate along-strike rupture propagation with and without inelastic wedge failure and examine how they may significantly affect tsunami and ocean acoustic waves. Test and extract signals that can be used in tsunami early warning. (iii) Develop dynamic rupture models of representative tsunami earthquakes and simulate waveforms to regional/teleseismic distances. Examine the resolving power of teleseismic, high-rate GPS, and tsunami data.