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

整合三维地震破裂动力学、海洋声波和海啸：增生楔中非弹性破坏的影响

• 批准号: 1620101
• 负责人: Shuo Ma
• 金额: $ 27.27万
• 依托单位: San Diego State University Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2022-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1620101&HistoricalAwards=false
• 关键词: Integrating; Three; Dimensional; Earthquake; Rupture

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.

浅层俯冲带(上10 ？15公里)在浅倾板块界面上发生地震，并有效地产生海啸。然而，地震破裂产生海啸的物理原理还没有得到很好的理解。本研究将研究人员之前的地震破裂模型扩展到三维，并将这些模型与海洋声波和海啸模型相结合。地震破裂与海洋声波和海啸的完全耦合系统为理解这些地震和海啸产生的物理学提供了主要的理论手段。这些模型还可以提取有用的信号，用于区分潜在机制和海啸预警。本文解决了地震力学中尚未解决的主要问题之一：浅层俯冲带异常破裂特征和海啸成因的物理性质。为什么这些地震能有效地产生海啸，却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矩标辐射能量？海啸是由海沟附近的大浅层滑动引起的，还是分布在楔形的非弹性变形引起的，还是两者兼而有之？海洋声波能否用于海啸预警？随时间变化的海底变形如何影响近场海啸？这个为期三年的研究项目将包括以下活动：(i)开发一种更新的拉格朗日有限元方法，以二维和三维的方式将海啸和海洋声波与地震破裂完全耦合，并使用现有的欧拉方法进行验证。（ii）模拟有无非弹性楔块破坏的沿走向破裂传播，并检查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。发展有代表性的海啸地震的动态破裂模型，模拟区域/远震距离的波形。检查远震、高速率GPS和海啸数据的分辨能力。