Upgrade of a Triaxial Rock Deformation Apparatus to Measure the Rheology of Subduction Megathrusts

升级三轴岩石变形仪以测量俯冲巨型逆冲断层的流变学

• 批准号: 1921517
• 负责人: Melodie French
• 金额: $ 10.24万
• 依托单位: William Marsh Rice University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1921517&HistoricalAwards=false
• 关键词: Upgrade; Triaxial; Rock; Deformation; Apparatus

Earthquakes are felt as elastic waves that shake the ground, but the cause of these waves is slip along faults kilometers beneath the surface. Not all faults produce earthquakes, however, and the reasons that some faults slip destructively in earthquakes, whereas others slip so slowly that they do not produce elastic waves are not entirely known. The faults associated with the greatest hazards are found at subduction plate boundaries, such as the Pacific Northwest of the United States. These faults create the largest earthquakes and associated tsunamis, but they are also the least understood. Whether a fault slips destructively or not is controlled by the mechanical properties of the rocks within the fault zone. This proposal will fund the upgrade of equipment that will be used to measure the mechanical properties of rocks from subduction plate boundary faults. The results of these measurements will be used to determine how the rocks present in a given region determine how the faults slip, whether in an earthquake or less destructively. The measurements made by this equipment will, therefore, contribute to improved models of seismic hazards for populous regions, such as the Pacific Northwest.The physical properties of rocks along the subduction plate boundary are thought to affect the depths of transitions between aseismic and seismic slip, and phenomena such as slow slip, low-frequency earthquakes, and tremor. However, there is still considerable uncertainty about which lithologies and which properties control these processes in subduction zones, in part because the minerals present in subduction zones are both more varied and more challenging to study. This award will upgrade a triaxial rock deformation apparatus donated to Rice University for the purpose of studying the constitutive behavior of rocks present along the subduction plate boundary. The apparatus will be used to measure the constitutive behavior at temperatures that span the seismogenic zone (500 degrees C) and over 8 orders of magnitude in strain rate. These constitutive relations can then be used in models of fault slip along subduction megathrusts to understand how far landward and seaward earthquakes might propagate, which will inform seismic hazards associated with ground shaking and tsunamis, respectively. The project will fund the development of a rock deformation laboratory by an early career PI and the upgraded apparatus will be used by students to conduct their thesis research. Lab members will communicate to the public about this research through a social media account.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.

地震被认为是弹性的波浪，但这些波的原因是沿着表面下方的断层沿断层滑落。但是，并非所有的断层都会产生地震，而某些断层在地震中破坏性的原因，而另一些断层则慢慢滑动，以至于它们不会产生弹性波。与最大危害相关的断层在俯冲板边界，例如美国西北太平洋。这些断层造成了最大的地震和相关的海啸，但它们也是最了解的。故障是否破坏性地滑动是由断层区域内岩石的机械性能控制的。该提案将资助用于测量俯冲板边界断层岩石的机械性能的设备升级。这些测量结果的结果将用于确定给定区域中存在的岩石如何确定断层滑移的方式，无论是在地震中还是破坏性地。因此，该设备进行的测量将有助于改善人口众多地区的地震危害模型，例如太平洋西北。 ，以及诸如慢速滑移，低频地震和震颤之类的现象。但是，对于哪些岩性和哪些特性控制俯冲带中的这些过程仍然存在很大的不确定性，部分原因是俯冲带中存在的矿物质既多样化又更具挑战性的研究。该奖项将升级捐赠给赖斯大学的三轴岩石变形设备，目的是研究沿俯冲板边界上存在的岩石的本构行为。该设备将用于测量跨越地震区（500度C）的温度和应变率以上8个数量级的构成行为。 然后，这些构成关系可以用于沿俯冲层的断层滑移模型中，以了解地震可能会传播多远，这将分别为与地面震动和海啸有关的地震危害提供信息。该项目将资助早期职业生涯的岩石变形实验室的发展，学生将使用升级的机构进行论文研究。实验室成员将通过社交媒体帐户向公众沟通这项研究。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的评论标准来评估值得支持的。