EAR-PF The scale-dependent interplay between fault material strength, roughness and friction

EAR-PF 断层材料强度、粗糙度和摩擦力之间依赖于尺度的相互作用

基本信息

批准号：
2052594
负责人：
Valere Lambert
金额：
$ 17.4万
依托单位：
Lambert Valere R
依托单位国家：
美国
项目类别：
Fellowship Award
财政年份：
2021
资助国家：
美国
起止时间：
2021-06-01 至 2023-05-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2052594&HistoricalAwards=false
关键词：
EAR PF scale dependent interplay

项目摘要

Dr. Valère Lambert has been awarded an NSF EAR Postdoctoral Fellowship to investigate the ways that rock strength, the shape of a fault’s surface, and friction can affect the behavior of faults and thus hazards associated with earthquakes. The majority of what is known about the mechanics of faults comes from small-scale (1 meter) experiments but natural fault systems are much larger (tens to thousands of meters). Because laboratory experiments and numerical studies indicate that rock strength and friction measurements vary with scale, application of laboratory experiment results to natural systems requires careful consideration of how to adjust for differences between natural and laboratory scales. This study aims to establish a framework for scaling up by clarifying relationships among rock strength, the shape and roughness of the fault surface, and friction at a variety of scales. Determining a framework for appropriately-scaled descriptions of friction and rock strength has important implications for earthquake science and engineering. The project will also support research opportunities for undergraduate students as University of California Santa Cruz, as well as development of educational earthquake simulations and an outreach video series oriented towards the general public addressing topics in earthquake physics.Obtaining a better understanding of the relationship between fault material strength and the deformation of fault asperities at varying scales will contribute to our general understanding of fault topography evolution and frictional behavior. This project will assess the feasibility of using measurements of fault roughness as the basis for bridging laboratory and natural scales and aims to develop computational homogenization tools for determining macroscale material and structural features from microscale fault properties. The project will directly measure the scale-dependent material properties of natural fault samples in the laboratory and explore how the aggregate behavior of microstructural features, such as material heterogeneity and layering, maps into the yielding of surface asperities at varying scales. The project will then explore what role scale-dependent material strength plays in the evolution of fault roughness and the apparent frictional behavior under shear motion. This work will examine if there is an inherent link between scale-dependent material properties and structure, both in the topography of the interface as well as material layering. If such a relationship exists, this may form the basis to a scheme for inferring spatial trends in rock strength and extrapolating frictional behavior to field scales using extant measurements of fault roughness. Such an approach could have broad applications in materials science, including implications of material layering on frictional behavior.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.

ValèreLambert博士被授予了NSF耳朵博士后研究金，以研究摇滚强度，断层表面形状以及摩擦的形状的方式，会影响断层的行为，从而影响与地震相关的危害。关于断层力学的大多数知识来自小规模（1米）实验，但自然断层系统更大（数十万至千米）。由于实验室实验和数值研究表明，岩石的强度和摩擦测量随规模而变化，因此实验室实验结果在天然系统中的应用需要仔细考虑如何调整自然和实验室尺度之间的差异。这项研究旨在建立一个框架，以阐明岩石强度之间的关系，断层表面的形状和粗糙度以及各种尺度上的摩擦。确定适当尺寸的摩擦和岩石力量描述的框架对地震科学和工程学具有重要意义。该项目还将支持本科生作为加利福尼亚大学圣克鲁斯分校的研究机会，以及开发教育地震模拟的发展，以及针对地震物理学中的一般公众探讨主题的范围视频系列。对材料实力和虚假尺度上的故障apperition的关系之间的关系有更好的理解，可以使我们的缺陷尺度的变形对我们的一般性构成缺陷的构图和弗里克的一般理解和弗里克的一般理解和弗里克的效力，并将促进弗里克特的效果。该项目将评估使用断层粗糙度作为桥接实验室和自然尺度的基础的可行性，并旨在开发计算均质化工具，以确定微观材料和微观断层特性的结构特征。该项目将直接测量实验室中天然断层样品的规模依赖性材料特性，并探讨微观结构特征的骨料行为（例如材料异质性和分层）如何在不同尺度下屈服于表面不稳定的屈服。然后，该项目将探索在断层粗糙度的演变中尺度依赖性材料强度发挥哪些作用，以及在剪切运动下的明显摩擦行为。这项工作将检查是否在界面的地形以及材料分层之间是否存在依赖比例依赖的材料属性和结构之间的固有联系。如果存在这种关系，这可能是推断岩石强度的空间趋势和推断摩擦行为的方案的基础，并使用故障粗糙度的极端测量来推断摩擦行为。这种方法可能在材料科学中有广泛的应用，包括材料分层对摩擦行为的影响。该奖项反映了NSF的法定任务，并通过使用基金会的知识分子优点和更广泛的影响评估标准来评估值得支持。