Observations of Fault Growth Under Elevated Fluid Pressure Using Dynamic Microtomography

使用动态显微断层扫描观察高流体压力下的断层生长

基本信息

批准号：
1761912
负责人：
Wen-Lu Zhu
金额：
$ 35.86万
依托单位：
University of Maryland, College Park
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-06-01 至 2023-05-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1761912&HistoricalAwards=false
关键词：
Observations Fault Growth Under Elevated

项目摘要

Sudden motions of a tectonic fault such as the San Andreas fault cause earthquakes. Better seismic risk assessment requires quantitative knowledge of fault distribution and propagation. The discovery of slow slip events, those that occur over hours to months instead of seconds, at convergent plate boundaries, like in the Pacific Northwest, provides new opportunities to study the mechanics of earthquakes and other fault instabilities. Seismic observations link slow slip events to high fluid pressure within the fault zones but how this works mechanically is still unclear. Recent studies in the lab that emulate these conditions show that increasing pore pressure slow down fault growth. This project looks to advance these experiments to improve our understanding of the mechanics of slow faulting under high pore pressure. The work has broader impacts on our understanding of seismic hazards at coastal plate boundaries as well as other areas that see this type of complex faulting. The researcher will also provide a research experience for an undergraduate, and conduct outreach to a nearby high school to bring students into a scientific lab. The project supports a postdoctoral fellow and a graduate student.The researchers hypothesize that dilatant hardening at crack tip can cause deformation to migrate, which results in delocalized fracturing and slow fault propagation. To test this hypothesis, the work enables deformation experiments using an X-ray transparent deformation apparatus to record the real-time fault growth. The state-of-the-art dynamic microtomography imaging will elucidate the fault nucleation process and growth pattern in a deforming rock at in-situ conditions. They will also incorporate dilatancy hardening into the damage model to simulate the effect of pore pressure on fault propagation. Comparison of the 3-D microstructure generated by numerical simulations and the time-lapse tomography images will provide new insights into deformation mechanisms. The goal is to build a better understanding of the mechanics of slow fault growth, and thus provide the critical link between the geophysical observations and the stress states of a megathrust fault during the interseismic period of an earthquake cycle.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.

构造断层（如圣安德烈亚斯断层）的突然动作会导致地震。更好的地震风险评估需要对故障分布和传播的定量知识。慢速滑移事件的发现，那些发生在数小时到几个月而不是几秒钟的情况下，在收敛板边界（如太平洋西北部）提供了研究地震机制和其他断层不稳定性的新机会。地震观察结果将慢滑动事件与断层区域内的高流体压力联系起来，但是机械起作用的工作仍不清楚。模拟这些疾病的实验室的最新研究表明，孔压增加降低了断层的生长。该项目旨在推进这些实验，以提高我们对高孔压力下缓慢断层机制的理解。这项工作对我们对沿海板块边界的地震危害的理解以及其他看到这种复杂断层的领域产生了更大的影响。研究人员还将为本科生提供研究经验，并向附近的高中进行宣传，以将学生带入科学实验室。该项目支持博士后研究员和一名研究生。研究人员假设裂纹尖端的膨胀硬化可能会导致变形迁移，从而导致离域的压裂和缓慢的断层传播。为了检验该假设，该工作可以使用X射线透明变形设备来记录实时断层生长的变形实验。最先进的动态微视力学成像将阐明在原位条件下变形岩石中的断层成核过程和生长模式。他们还将将膨胀硬化融合到损伤模型中，以模拟孔隙压力对断层传播的影响。通过数值模拟和延时断层扫描图像生成的3-D微结构的比较将为变形机理提供新的见解。目的是更好地理解缓慢的断层生长的机制，从而在地震周期的跨界期间提供地球物理观察和大型断层的压力状态之间的关键联系。该奖项反映了NSF的法定任务，并通过使用该基金会的知识优点和广泛的影响来评估NSF的法定任务。

项目成果

期刊论文数量（11）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Dynamic In Situ Three-Dimensional Imaging and Digital Volume Correlation Analysis to Quantify Strain Localization and Fracture Coalescence in Sandstone

DOI：
10.1007/s00024-018-2003-x
发表时间：
2018-10
期刊：
Pure and Applied Geophysics
影响因子：
2
作者：
François Renard;J. McBeck;B. Cordonnier;Xiaojiao Zheng;Neelima Kandula;Jesus R. Sanchez;M. Kobchenko-M.-Kobchen
通讯作者：
François Renard;J. McBeck;B. Cordonnier;Xiaojiao Zheng;Neelima Kandula;Jesus R. Sanchez;M. Kobchenko-M.-Kobchen

The competition between fracture nucleation, propagation, and coalescence in dry and water-saturated crystalline rock