CAREER: Path Dependent Slip of the Shallow Subduction Megathrust

该项目是一个综合研究和教育计划，旨在研究在美国太平洋西北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下面的构造板块边界。它们是地球上最大的地震和海啸的发源地。这两种危险都是由沿边界存在的岩石的力学特性控制的。由于寄主岩石的矿物学不同，这些性质在区域上有所不同。当岩石被拖进俯冲带时，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，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质的影响。他们对目标板块边界采集的岩石试样进行变形实验。结果有助于揭示产生特大逆冲地震的断层的行为。它们还可以更好地评估区域灾害。这个项目包括对一位早期职业女性科学家的支持。此外，它还推动了一个由三部分组成的教育计划，以培养从K-12到本科和研究生水平的各级岩石力学学生。该奖项为期5年，由NSF地球物理学、构造学和海洋地质学和地球物理学项目共同资助。俯冲巨型逆冲断层的最浅层具有多种滑动模式，包括海啸型地震。浅层条件下的断层滑动模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。外在变量如何控制这些岩性的变形也不清楚。在这里，研究小组通过实验研究了浅俯冲带岩石的路径依赖强度和变形行为。该项目有一个基于现场的组件，以收集具有相关矿物学和微观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对不同滑移模式的影响；(3)实施移动教学实验室建设、探究式电子学课程建设、本科生科研与教学一体化的三部分教育计划。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.