CMG: Rheology of Damaged Materials with Applications to Deformation in the Earth's Crust

研究人员正在探索新的方法来表示在地壳损伤力学使用连续流变学。利用已经开发的用于理解液晶相变的方法，他们正在开发一种新的连续介质材料在剪切流动中的损伤模型。他们使用具有各向异性特性的流体相来模拟地壳变形，其中根据对准矢量的方向存储一些弹性能量。未损坏状态的特征在于方向矢量（指向矢）的随机对齐。缺陷可以在各种配置中引入，并适当对齐导向器。响应于剪切，点缺陷可以发展和合并以触发速度的尖峰，即滑移事件。这种滑动机制，随后愈合，提供了一个模型的形成微裂纹和粘滑行为的断层。智力优点：地壳和上地幔的变形对地震的起源和板块构造机制的影响。这个系统的行为的研究将解决损害的起源，形成的断层，断层滑动，愈合，在地壳中。更广泛的影响：通过开发新的损伤流变学模型，这个项目将解决导致地震的根本机制，一个基本的社会重要性的科学问题。连续介质中的损伤理论具有远远超出物理学的潜在意义，并且可以适用于其他连续介质材料中的损伤。 此外，该项目建立了物理学和应用数学之间的新合作，导致在这两个领域的新方法的发展，同时教育研究生和博士后学者。

The investigators are exploring new methods for representing damage mechanics in the Earth's crust using a continuum rheology. Using a method that has been developed for understanding phase transitions in liquid crystals, they are developing a new model of damage in a continuum material undergoing shear flow. They model crustal deformation using a fluid phase with anisotropic properties, in which some elastic energy is stored according to the direction of an alignment vector. The undamaged state is characterized by random alignment of the directional vectors (director). Defects can be introduced in various configurations with appropriate alignment of the directors. In response to shear, point defects can develop and merge to trigger spikes in the velocity, that is, slip events. This slip mechanism, followed by subsequent healing, provides a model for the formation of microcracks and stick-slip behavior on faults.Intellectual Merit: Deformation of the Earth's crust and upper mantle has implications for the origins of earthquakes and the mechanisms for plate tectonics. This study of the behavior of this system will address the origins of damage, formation of faults, fault slip, and healing, in the Earth's crust.Broader Impacts: By developing new models of damage rheology, this project will address the underlying mechanisms leading to earthquakes, a scientific problem of fundamental societal importance. A theory of damage in a continuum has potential implications well beyond geophysics, and could be applicable to damage in other continuum materials. In addition, this project establishes a new collaboration between geophysics and applied mathematics, leading to the development of new methods in both fields, while educating a graduate student and a postdoctoral scholar.