Subduction zone geodynamics and earthquake processes

这项提案寻求有限的资金，在未来五年的任何一年为两到三名研究生提供部分支持，作为我研究计划的一部分。拟议中的研究旨在了解俯冲带的工作，其中加拿大西海岸的卡斯卡迪亚俯冲带是一个离家不远的例子。学生们将研究是什么使巨型逆冲断层产生大地震，是什么使它们在缓慢滑动事件中蠕动，应力如何在地震周期中积累和释放，以影响上板块的地质，是否以及为什么相隔很远的地区的地震活动是物理连接的，等等。拟议的研究涉及基本的地球动力学，它有助于社会了解是什么原因造成地震和海啸灾害。我们的主要方法是使用计算机建模来解释全球多学科观测，以揭示潜在的物理原理。指导学生从大量的观测和基本原理中发展地球动力学概念，而不仅仅是从教科书和传统模型中发展。为了了解俯冲边缘的地球动力学，特别是控制地震生成的过程，我们将在未来五年内在三个相互关联的研究方向上进行。第一个方向是探索地震旋回变形与地质变形之间的联系。我们需要研究世界各地的俯冲边缘，并开发具有现实但复杂的力学特性的模型，以研究单个和多个地震周期的应力和结构演化。第二个方向是研究地球较浅和较硬的部分（岩石圈）和较深和较软的部分（软流圈）的解耦是否可以解释看似神秘的远距离相互作用，无论是在同一俯冲带还是在不同的俯冲带。第三个方向是解决温度和流体如何控制俯冲断层的滑动行为，特别是开发一个统一的模型来解释缓慢滑动事件的地球物理条件以及这些事件与产生大地震的断层部分的关系。**

This proposal seeks limited funds to provide partial support for two to three graduate students at any given year over the next five years as part of my research program. The proposed research is designed to understand the works of subduction zones, for which the Cascadia subduction zone off Canada's west coast is a near-home example. The students will study what enables megathrust faults to generate large earthquakes and what makes them creep in slow slip events, how stress is built up and relieved in earthquake cycles to affect the geology of the upper plate, whether and why seismic activities in areas very far apart are physically connected, and so forth. The proposed research addresses fundamental geodynamics, and it helps society to understand what causes seismic and tsunami hazards. 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 goal of understanding the geodynamics of subduction margins, especially processes that govern earthquake generation, we will proceed in three interrelated research directions over the next five years. The first direction is to explore the link between earthquake cycle deformation and geological deformation. We need to examine subduction margins around the world and develop models with realistic, although complex, mechanical properties to investigate stress and structural evolution over individual and multiple earthquake cycles. The second direction is to study whether the decoupling of the shallow and harder part the Earth (the lithosphere) and the deeper and softer part (the asthenosphere) can explain seemingly mysterious long-range interactions of regions very far apart, either in the same subduction zone or in different subduction zones. The third direction is to address how temperature and fluids control the slip behaviour of subduction faults, in particular to develop a unified model to explain geophysical conditions for slow slip events and the relation of these events with the part of the fault that generates great earthquakes. **