Geodynamics and earthquakes in subduction zones and lithosphere

俯冲带和岩石圈的地球动力学和地震

• 批准号: RGPIN-2022-03861
• 负责人: Wang, Kelin
• 金额: $ 3.13万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=750987
• 关键词: Geodynamics; earthquakes; subduction; zones; lithosphere

With this application, I seek funds to provide partial support for two to three graduate students at any given year over the next five years. The proposed fundamental research is focused mainly on earthquake processes in subduction zones. The anticipated "big one" from the Cascadia subduction zone that threatens Canada's west coast is a near-home example to exemplify the societal relevance of the research. The students will study what controls the downdip extension of megathrust rupture, how shallow rupture contributes to tsunami generation, how the viscoelastic behaviour of Earth's mantle controls earthquake cycles, what crustal deformation observed today tells us about the next earthquake, how tectonic loading governs the state of stress in subduction zones and the lithosphere, what stress and structural environments enable earthquakes, and so forth. Our main method is to use computer modelling to explain global multidisciplinary observations to reveal underlying physical principles. The students are directed to develop geodynamic concepts from large volumes of observations and basic principles, not merely from textbooks and conventional models. With the long-term objective of understand the geodynamics of convergent margins and its larger tectonic environment, we will conduct research in three directions over the next five years. The first direction is about how the Earth's crust builds up energy for the next earthquake. The process begins right after the previous earthquake and proceeds in a complex fashion towards the next earthquake. It is controlled by the viscoelastic behaviour of the mantle. We will develop new viscoelastic earthquake cycle models and gain improved understanding of the deformation process. The results will guide the use of contemporary crustal deformation observations to evaluate seismic potential. The second direction is about earthquake rupture itself. We will study what enables or stops megathrust rupture to depths as large as 50 km or greater, factors including temperature and fault zone material. We will also study how the rupture of the shallow end of the megathrust deforms the seafloor to generate tsunamis. For both the shallow and deep parts, we question conventional concepts and aim to develop new theories. The results will contribute to the assessment of seismic and tsunami hazards and the design of early warning systems. The third direction is about how tectonic forces cause earthquakes. We will study the state of stress in subduction zones and the lithosphere, including investigating a paradox regarding earthquake occurrence under seemingly very low stresses. The results will yield new understanding of the mechanics of earthquake generation and guide future research in linking long-term tectonics to earthquake hazards.

通过此申请，我寻求资金在未来五年的任何一年中为两到三名研究生提供部分支持。拟议的基础研究主要集中在俯冲带中的地震过程上。威胁加拿大西海岸的卡斯卡迪亚俯冲区的预期“大个子”是一个近乎家庭的例子，可以体现这项研究的社会意义。 The students will study what controls the downdip extension of megathrust rupture, how shallow rupture contributes to tsunami generation, how the viscoelastic behaviour of Earth's mantle controls earthquake cycles, what crustal deformation observed today tells us about the next earthquake, how tectonic loading governs the state of stress in subduction zones and the lithosphere, what stress and structural environments enable地震，等等。我们的主要方法是使用计算机建模来解释全球多学科观察，以揭示基本的物理原理。这些学生被指示从大量观察和基本原理中发展出地球动力学概念，而不仅仅是教科书和传统模型。凭借理解收敛利润率及其较大构造环境的地球动力学的长期目标，我们将在未来五年内在三个方向进行研究。第一个方向是关于地球的地壳如何为下一次地震积累能量。该过程在上一场地震之后开始，并以复杂的方式朝着下一次地震进行。它由地幔的粘弹性行为控制。我们将开发新的粘弹性地震周期模型，并提高人们对变形过程的理解。结果将指导使用当代地壳变形观测值来评估地震潜力。第二个方向是关于地震破裂本身。我们将研究有助于或阻止大型破裂到50公里或更高的深度，包括温度和断层区域材料的因素。我们还将研究大型巨星浅端的破裂如何使海底变形以产生海啸。对于浅层和深层部分，我们质疑传统的概念，并旨在发展新理论。结果将有助于评估地震和海啸危害以及预警系统的设计。第三个方向是关于构造力如何引起地震。我们将研究俯冲带和岩石圈的压力状态，包括研究在看似非常低的应力下发生地震发生的悖论。结果将对地震产生的力学产生新的了解，并指导将来的研究将长期构造与地震危害联系起来。