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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博士被授予NSF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的行为，从而影响与地震相关的危害。关于断层力学的大部分知识来自小规模（1米）实验，但天然断层系统要大得多（数万米）。由于实验室实验和数值研究表明，岩石强度和摩擦测量随尺度而变化，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。本研究旨在通过澄清岩石强度、断层面形状和粗糙度以及各种尺度下的摩擦力之间的关系，建立一个按比例放大的框架。确定一个框架，适当规模的摩擦和岩石强度的描述有重要意义的地震科学和工程。该项目还将支持本科生的研究机会，因为加州大学圣克鲁斯，以及开发教育地震模拟和面向公众的宣传视频系列，以解决地震物理学问题。更好地了解断层材料强度与不同尺度断层粗糙体变形之间的关系，将有助于我们对断层的一般理解地形演化和摩擦行为。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，并旨在开发计算均匀化工具，用于从微观断层特性确定宏观尺度材料和结构特征。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的聚集行为，如材料异质性和分层，如何映射到不同尺度的表面粗糙度的屈服。该项目将探讨尺度相关的材料强度在断层粗糙度的演变和剪切运动下的表观摩擦行为中起什么作用。这项工作将检查是否有一个内在的联系之间的比例依赖的材料性能和结构，无论是在界面的地形以及材料分层。如果存在这样的关系，这可能会形成一个方案的基础，用于推断岩石强度的空间趋势和外推摩擦行为，使用现有的断层粗糙度测量现场规模。这种方法可以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的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。