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.

这个项目是一个综合性的研究和教育计划，旨在研究在美国西北太平洋等构造环境中产生地震和海啸的过程。“俯冲带”是一个板块俯冲到另一个板块之下的构造板块边界。它们是地球上最大的地震和海啸的发源地。这两种危险都是由边界沿线岩石的力学性质控制的。由于寄主岩石中矿物学的不同，这些性质在区域上也不同。当岩石被拖入俯冲带时，它们也会经历不同的物理和化学变化。这些变化也会影响它们的机械性能。在这里，该团队研究了不同物理和化学路径对俯冲带岩石力学性质的影响。他们对在目标板块边界收集的岩石样本进行变形实验。研究结果有助于揭示产生巨型逆冲地震的断层的行为。它们还可以更好地评估地区性危害。该项目包括对一位职业生涯早期的女科学家的支持。此外，它还促进了一个由三部分组成的教育计划，以培训从K-12到本科生和研究生的所有级别的学生岩石力学。这项为期5年的奖项由美国国家科学基金会地球物理、构造和海洋地质及地球物理项目共同资助。最浅程度的俯冲巨型逆冲具有多种滑动模式，包括引发海啸的地震。浅层条件下的断层滑动方式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。然而，目前还没有岩性控制滑动行为的综合模型。外部变量如何控制这些岩性的变形也不清楚。在这里，该团队对浅俯冲带岩石的路径依赖强度和变形行为进行了实验研究。该项目有一个以实地为基础的组成部分，用于收集具有相关矿物学和显微结构的自然变形标本。研究和教育计划的目标是：(1)确定俯冲沉积物和玄武岩所经历的矿物学和孔隙度的变化如何促进或抑制不同的滑动模式；(2)量化导致孔隙流体压力升高的路径如何影响不同的滑动模式；(3)启动一个由三部分组成的教育计划，其中包括开发一个移动教学实验室，一个基于探究的电子课程，以及将本科生纳入研究和教学活动。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。