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Faulting and healing of the crust throughout the seismic cycle: From microscale physico-chemical processes to a global rheology

整个地震周期中地壳的断层和愈合：从微观物理化学过程到全球流变学

基本信息

批准号：
NE/K009656/1
负责人：
Nicolas Brantut
金额：
$ 68.9万
依托单位：
University College London
依托单位国家：
英国
项目类别：
Fellowship
财政年份：
2013
资助国家：
英国
起止时间：
2013 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FK009656%2F1
关键词：
Faulting healing crust throughout seismic

项目摘要

In the Earth's upper crust, geological deformation is primarily accommodated by fracturingand faulting. Fault motion can be catastrophic and generate earthquakes, but these are rather rare events in time: most faults in the crust are either very slowly moving (creeping) or completely locked between earthquakes. During this so-called interseismic period, fractures heal (i.e., they regain strength) and seal (i.e., they close paths for fluid flow) due to chemical lithification processes. The competition of healing and sealing processes with fracture growth conditions the location and timing of future earthquakes along faults. Hence, understanding how rocks heal and fracture, and the feedbacks between these processes, is an essential step towards a better knowledge of earthquake generation and the associatedhazards. Despite the considerable attention this problem has received since the late 1970's,mostly through the development of phenomenological frictional constitutive laws, very little isknown in terms of actual microscale mechanisms, from which the observed empirical macroscopic laws couldarise. In particular, a unifying micromechanical framework encompassing fracture gowth, healing andsealing remains to be determined. Therefore, I propose to tackle this problem from a different pointof view, by (1) identifying and quantifying experimentally the physico-chemical processes controllingultra-slow deformation and fracture healing, and (2) theoretically input those processes into a rigorousmicromechanical framework that can be used to extrapolate from the laboratory to field scale.

在地球上地壳，地质变形主要由破裂和断层作用来调节。断层运动可能是灾难性的，并引发地震，但这些在时间上是相当罕见的事件：地壳中的大多数断层要么移动非常缓慢(蠕动)，要么在地震之间完全锁定。在这个所谓的地震间期，由于化学岩化作用，裂缝愈合(即它们恢复强度)和封闭(即它们关闭了流体流动的路径)。愈合和封闭过程与裂缝生长条件的竞争决定了未来沿断层发生地震的地点和时间。因此，了解岩石如何愈合和破裂，以及这些过程之间的反馈，是更好地了解地震孕育和相关灾害的关键一步。尽管这个问题自70年代末以来得到了相当大的关注，但主要是通过唯象摩擦本构定律的发展，对实际的微观机制知之甚少，从中观察到的经验宏观规律可以解释。特别是，包含骨折生长、愈合和闭合的统一微观力学框架仍有待确定。因此，我建议从一个不同的角度来解决这个问题，方法是(1)从实验上识别和量化控制超慢变形和骨折愈合的物理化学过程，(2)从理论上将这些过程输入到一个严格的微观机械框架中，可以用来从实验室到现场范围进行推断。