Geodynamics and earthquakes of subduction zones

俯冲带的地球动力学和地震

• 批准号: 227412-2011
• 负责人: Wang, Kelin
• 金额: $ 2.33万
• 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: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=523971
• 关键词: Geodynamics; earthquakes; subduction; zones

The proposed research is designed to understand mechanical processes of subduction zones. The findings will have important implications for understanding the geodynamics of plate subduction, especially its earthquake processes. This proposal seeks limited funding to provide partial support for two graduate students at any given year over the next five years to conduct computer modeling on three subjects. The first subject is the deformation cycles of great subduction earthquakes such as the M 9 earthquake in 1700 off Canada's west coast. Based on geodetic and seismological observations from different subduction zones, we will develop models to address how the Earth's crust and mantle deform during and after an earthquake and how strain energy is re-accumulated leading to the next event. The second subject is the Episodic Tremor and Slip (ETS), a phenomenon newly found downdip of the seismogenic zone of some subduction faults, such as at the Cascadia subduction zone off the west coast. This will help us understand the complex behavior of subduction faults, that is, why and how they slip not only in earthquakes but also in aseismic slip transients during the time between earthquakes. The third subject is geometrical and structural controls on great subduction earthquakes. Earthquake rupture is a manifestation of unstable friction, but subduction faults are not discrete frictional contacts but zones of three-dimensional structural complexity. We will work on a new conceptual framework that will allow us to address many unanswered first-order questions such as why the Cascadia subduction zone tends to produce infrequent but giant (M ~ 9) earthquakes while many other subduction zones tend to produce more frequent but smaller events.

拟议的研究旨在了解俯冲区的机械过程。这些发现将对理解板俯冲的地球动力学，尤其是其地震过程具有重要意义。该提案寻求有限的资金，在未来五年内的任何一年中为两名研究生提供部分支持，以对三个科目进行计算机建模。第一个主题是俯冲地震的变形周期，例如加拿大西海岸1700年的M 9地震。基于不同俯冲区的大地测量和地震学观察结果，我们将开发模型，以解决地震期间和之后地球的地壳和地幔的变形以及如何重新蓄能菌株能量，从而导致下一个事件。第二个主题是情节震颤和滑移（ETS），这是一种新发现的某些俯冲断层的地震源性区域的现象，例如在西海岸附近的卡斯卡迪亚俯冲带。这将有助于我们了解俯冲断层的复杂行为，即，为什么以及它们在地震之间的地震中，而且在无性滑移瞬变中的原因和方式。第三个受试者是俯冲地震的几何和结构控制。地震破裂是不稳定摩擦的一种表现，但俯冲断层不是离散的摩擦接触，而是三维结构复杂性的区域。我们将在一个新的概念框架上工作，该概念框架将使我们能够解决许多未解决的一阶问题，例如为什么卡斯卡迪亚俯冲带倾向于会产生不常见但巨大的（M〜9）地震，而许多其他俯冲区往往会产生更频繁但更小的事件。