Collaborative Research: The rheological behavior of gouge at high temperature

合作研究：高温下凿岩的流变行为

• 批准号: 2240735
• 负责人: Heather Savage
• 金额: $ 10.16万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2240735&HistoricalAwards=false
• 关键词: Collaborative; Research; rheological; behavior; gouge

Major earthquakes are generated along faults in Earth’s tectonic plates as rocks are sheared past each other. Assessing the hazard associated with a fault zone requires understanding the conditions that promote earthquake nucleation. Shearing on faults can occur in an unstable manner, where rapid slip allows an earthquake to nucleate, or in a stable manner, where slip is steady and suppresses earthquake nucleation. Although much work has been devoted to understanding the conditions that lead to earthquake nucleation in the relatively cold portions of Earth’s crust, there is still a considerable gap in knowledge regarding the stability of faults in hotter regions. These hotter regions include the conduits of explosive volcanoes and transform faults in the oceans. Our work will determine the influence of temperature on fault stability to enable accurate assessments of hazard and risk in these regions. This work will also provide training to early-career researchers at the postdoctoral, graduate, and undergraduate levels. The team involved in this research will also work to introduce high-temperature experimental rock physics to groups typically underrepresented in the sciences via international conferences, and they will run a short-course on earthquakes and faulting to be offered to early-career researchers around the world in an in-person and virtual format.We will specifically answer three questions related to fault stability at high temperatures. First, how do extreme temperatures affect the strength and stability of fault materials? To answer this question, we will conduct deformation experiments on fault materials over a wide range of conditions. Second, what microscopic mechanisms control the strength of fault materials, and how do they compete with one another? To answer this question, we will use high-resolution microscopy to compare mechanical measurements with theoretical models based on the microphysics of rock deformation. Third, how do these mechanisms interact to determine fault stability, and what does this mean for the depth range of earthquakes in natural settings? To answer this question, we will assess the relationships among microscopic features, the macroscopic strength, the observed stability, and the rate of deformation. The net result of these observations will be a refined model for the stability of fault zones at high temperatures, which we will then compare to available catalogs of earthquake locations in relatively “hot” regions to test our predictions of the depth range of earthquake nucleation.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.

当岩石相互剪切时，大地震会沿着地球构造板块的断层产生。评估与断层带相关的危险需要了解促进断层上的地震成核的条件，其中快速滑动会导致地震发生。地震成核，或者以稳定的方式，滑移稳定并抑制地震成核，尽管人们已经做了很多工作来了解在相对寒冷的情况下导致地震成核的条件。在地壳的某些部分，关于较热区域断层稳定性的知识仍然存在相当大的差距，这些较热区域包括爆发性火山的通道和海洋中的转换断层，我们的工作将确定温度对断层稳定性的影响。这项工作还将为博士后、研究生和本科生级别的早期研究人员提供培训，并致力于介绍高温实验岩石物理学。通常到团体通过国际会议在科学领域代表性不足，他们将以面对面和虚拟的形式向世界各地的早期职业研究人员提供有关地震和断层的短期课程。我们将具体回答与断层稳定性相关的三个问题首先，极端温度如何影响断层材料的强度和稳定性？为了回答这个问题，我们将在多种条件下对断层材料进行变形实验，其次，什么微观机制控制断层材料的强度。 ，以及他们如何与为了回答这个问题，我们将使用高分辨率显微镜将力学测量结果与基于岩石变形微观物理学的理论模型进行比较。第三，这些机制如何相互作用来确定断层稳定性，这对深度意味着什么。为了回答这个问题，我们将评估微观特征、宏观强度、观测到的稳定性和变形率之间的关系，这些观测的最终结果将是一个精确的稳定性模型。高断层带然后，我们将其与相对“热”地区的现有地震位置目录进行比较，以测试我们对地震成核深度范围的预测。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力评估进行评估，被认为值得支持优点和更广泛的影响审查标准。