The collective behavior of deep fault asperities during non-volcanic tremor and slow slip

这个项目探索了一个最近发现的地球物理现象，非火山震颤，其物理起源尚不清楚。这个多部分项目将理论、观测和实验以协同的方式结合起来，并聚集了一个在观测地震学、计算建模和实验断裂力学等几个领域具有专业知识的团队。该项目将利用来自两个不同地区和实验室实验的数据，提供新的观测结果。虽然以前已经通过模型和实验解决了偶发性慢滑瞬变的相关现象，但非火山性震颤的模拟和计算建模只是刚刚开始。拟议的研究旨在填补这一空白，同时为大型数据集分析、多尺度计算建模和结合光学和声学成像裂缝技术的创新方法做出贡献。拟议的研究涉及美国和南美洲高度暴露于地震危险的地区。本文提出的问题是，理解非有机物去除与发震带力学之间的关系，可以为地震危险性评估提供重要的输入。如果NVT活动被证明是一个天然的蠕变计，它将提供一种远程监测与大地震成核有关的小地震滑动瞬变的手段。该项目将为现场试验研究NVT提供新的靶点。它将加强和多样化两名博士后研究员的专业知识，并将为一名研究生提供培训。该项目由三个部分组成：(1)观测部分提出了在南加州和秘鲁-智利俯冲带的地震波形数据集中系统搜索NVT的建议；(2)一个理论和计算部分，涉及多尺度建模方法的发展，以及在速率和状态模型中研究震颤和慢滑期间岩石的集体行为及其对瞬态和周期性应力的响应；(3)实验组件，将解决瞬态和周期性载荷对故障响应的影响。

This project explores a recently discovered geophysical phenomenon, non-volcanic tremor, whose physical origins are not yet known. This multi-component project combines theory, observations and experiments in a synergistic way, and gathers a team with expertise in several areas: observational seismology, computational modeling and experimental fracture mechanics. The project will provide new observations, employing data from two distinct regions and from laboratory experiments. Whereas the related phenomenon of episodic slow slip transients has been previously addressed by models and experiments, analog and computational modeling of non-volcanic tremor is only incipient. The proposed research aims at filling that gap while contributing with innovative methodologies in large dataset analysis, multi-scale computational modelling and combined optical and acoustic techniques for imaging fracture. The proposed studies concern regions of the United States and South America that are highly exposed to earthquake hazard. Understanding the relations between non-vocanic remor and mechanics of seismogenic zones, a question addressed by this proposal, can provide important input for earthquake hazard assessment. If NVT activity proves to be a natural creepmeter it will provide a means to remotely monitor the small aseismic slip transients related to the nucleation of large earthquakes. The project will provide new targets for field experiments to study NVT. It will enhance and diversify the expertise of two post-doctoral fellows and will provide training for a graduate student.This project consists of three components: (1) an observational component proposing a systematic search for NVT in seismic waveform datasets from Southern California and from the Peru-Chile subduction zone; (2) a theoretical and computational component involving the development of a multi-scale modelling approach and studies of the collective behavior of asperities during tremor and slow slip in rate- and- state models and their response to transient and periodic stresses; and (3) an experimental component that will address the effect of transient and periodic loads on the response of fault asperities.