CAREER: Path Dependent Slip of the Shallow Subduction Megathrust

事业：浅俯冲巨型逆冲断层的路径相关滑动

• 批准号: 1945264
• 负责人: Melodie French
• 金额: $ 60.17万
• 依托单位: William Marsh Rice University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1945264&HistoricalAwards=false
• 关键词: CAREER; Path; Dependent; Slip; Shallow

This project is an integrated research and education plan to study the processes generating earthquakes and tsunamis in tectonic environments like the Pacific Northwest of the United States. "Subduction zones" are tectonic plate boundaries where one plate dives beneath another. They host Earth’s largest earthquakes and tsunamis. Both hazards are controlled by the mechanical properties of the rocks present along the boundary. These properties vary regionally due to different mineralogy in the host rocks. Rocks also undergo different physical and chemical changes as they are dragged into a subduction zone. These changes affect their mechanical properties as well. Here, the team study the effects of different physical and chemical paths on the mechanical properties of subduction-zone rocks. They carry out deformation experiments on rock specimens collected in targeted plate boundaries. Results helps unveiling the behavior of faults generating megathrust earthquakes. They also allow better assessing regional hazards. This project includes support for an early-career female scientist. In addition, it promotes a 3-part education plan to train students in rock mechanics at all levels, from K-12, to undergraduate and graduate levels. The 5-year award is co-funded by NSF Geophysics, Tectonics, and Marine Geology & Geophysics programs. The shallowest extent of subduction megathrusts hosts a variety of slip modes, including tsunamigenic earthquakes. The mode of fault slip at shallow conditions is proposed to be controlled by the physical properties of the sediments and rocks along the plate boundary, as well as external conditions like pore fluid pressure and temperature. However, there is no comprehensive model for which lithologies control slip behavior. How extrinsic variables control the deformation of these lithologies is also unclear. Here, the team studies experimentally the path-dependent strength and deformation behavior of shallow subduction-zone rocks. The project has a field-based component to collect naturally deformed specimens with relevant mineralogy and microstructures. The goals of the research and education plan are: (1) to determine how changes in mineralogy and porosity, experienced by subducted sediments and basalt, promote or inhibit different slip modes; (2) to quantify how the paths that lead to elevated pore fluid pressures affect different modes of slip; (3) to launch a 3-part education plan that includes the development of a mobile teaching laboratory, that of an inquiry-based electronics course, and the integration of undergraduate students in research and teaching activities.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该项目是一项综合研究和教育计划，旨在研究在美国西北部太平洋地区的构造环境中产生地震和海啸的过程。“俯冲带”是构造板块的边界，其中一个板块俯冲到另一个板块下方，它们发生了地球上最大的地震。这两种灾害都是由边界沿线岩石的机械特性控制的，由于母岩的矿物学不同，这些特性在被拖曳时也会发生不同的物理和化学变化。这些变化也会影响它们的力学性能，研究小组研究了不同的物理和化学路径对俯冲带岩石力学性能的影响。结果有助于揭示断​​层产生大逆冲地震的行为，还可以更好地评估区域灾害。此外，它还促进了一项由三部分组成的教育计划，对学生进行岩石力学培训。水平，该奖项为期 5 年，由 NSF 地球物理学、构造学和海洋地质学与地球物理学项目共同资助。浅层条件下的断层滑动模式被认为受板块边界沉积物和岩石的物理性质以及孔隙流体压力和温度等外部条件的控制。目前尚不清楚外在变量如何控制这些岩性的变形，该团队通过实验研究了浅俯冲带岩石的路径相关强度和变形行为。收集具有相关矿物学和微观结构的自然变形样本的组件 研究和教育计划的目标是：（1）确定俯冲沉积物经历的矿物学和孔隙度的变化。玄武岩，促进或抑制不同的滑移模式；（2）量化导致孔隙流体压力升高的路径如何影响不同的滑移模式；（3）启动一个由三部分组成的教育计划，其中包括开发移动教学实验室该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。