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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.

Valère Lambert 博士获得了 NSF EAR 博士后奖学金，以研究岩石强度、断层表面形状和摩擦力如何影响断层行为以及与地震相关的危害。关于断层力学的大部分知识都来自小规模（1 米）实验，但自然断层系统要大得多（数十到数千米）。由于实验室实验和数值研究表明岩石强度和摩擦力测量值随尺度而变化，因此将实验室实验结果应用于自然系统需要仔细考虑如何调整自然尺度和实验室尺度之间的差异。本研究旨在通过阐明岩石强度、断层表面的形状和粗糙度以及各种尺度的摩擦之间的关系，建立一个扩大规模的框架。确定适当尺度的摩擦力和岩石强度描述框架对于地震科学和工程具有重要意义。该项目还将支持加州大学圣克鲁斯分校本科生的研究机会，以及开发教育性地震模拟和面向公众的地震物理主题的外展视频系列。更好地了解不同尺度的断层材料强度和断层粗糙体变形之间的关系将有助于我们对断层地形演化和摩擦行为的总体理解。该项目将评估使用断层粗糙度测量作为连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，用于根据微观断层特性确定宏观材料和结构特征。该项目将在实验室中直接测量自然断层样本的尺度相关材料特性，并探索微观结构特征（例如材料异质性和分层）的聚合行为如何映射到不同尺度的表面粗糙度的屈服。然后，该项目将探讨尺度相关的材料强度在断层粗糙度的演变以及剪切运动下的表观摩擦行为中发挥的作用。这项工作将检查尺寸相关的材料属性和结构之间是否存在内在联系，无论是在界面的形貌还是材料分层方面。如果存在这种关系，这可能会成为推断岩石强度空间趋势并使用现有断层粗糙度测量将摩擦行为外推到现场尺度的方案的基础。这种方法可以在材料科学中得到广泛的应用，包括材料分层对摩擦行为的影响。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。