Elastodynamic Event Sequences on Rough Faults

断层的几何和物质非均质性一直被视为影响地震行为的重要特征。最近，应力不均匀性的作用已经开始被认为是一个潜在的中心特征，特别是有证据表明，应力不均匀性本身已经可以在均匀的平面断层上产生一组非常丰富和复杂的类似地震的行为。缺少的是如何理解两种类型的非均质，静态几何和材料的非均质，以及动态应力的非均质，可能结合和相互作用，以产生更现实的行为。本研究旨在进一步发展一种将弹性动力学模拟扩展到非平面几何的建模方法。具体地说，目标是开发粗略断层几何形状的模拟。通过对断层上长序列事件的研究，形成了动态吸引子，从而可以研究应力非均质性与任何几何非均质性的相互作用。在开发这项技术的同时，我们还将该模型应用于一系列观测，包括正常应力效应、破裂的开始和终止以及余震。这些应用有助于更好地理解摩擦，改进基于分段的长期危害估计，以及基于余震的短期危害估计。

Geometrical and material heterogeneities in faults have long been viewed as a crucial feature affecting earthquake behavior. More recently, the role ofstress heterogeneities has begun to be recognized as a potentially central feature,particularly with the demonstration that stress heterogeneities alone already can produce a remarkably rich and complex set of earthquake-likebehaviors on uniform planar faults. What is missing is an understanding of howthe two types of heterogeneities, the static geometrical and materialheterogeneities, and the dynamic stress heterogeneities, might combineand interact to produce even more realistic behavior.This research seeks to further develop a line of modeling which extends elastodynamic simulations to nonplanar geometries. Specifically, the aim is to develop simulations of rough fault geometries.By studying long sequences of events on the faults, the dynamical attractordevelops, and thus the interaction of stress heterogeneities with anygeometrical heterogeneities can be examined. As well as developing the technology, we are applying the modelto a set of observations, including normal stress effects, ruptureinitiation and termination, and aftershocks. These applicationshave relevance to understanding friction better, improving long term hazard estimation based on segmentation, and short term hazard estimationbased on aftershocks.