Surface wave triggering of earthquakes and non-volcanic tremor: Insights into the physics of rupture

地震和非火山颤动的表面波触发：对破裂物理学的见解

• 批准号: 0944257
• 负责人: Aaron Velasco
• 金额: $ 24.97万
• 依托单位: University of Texas at El Paso
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-01 至 2013-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0944257&HistoricalAwards=false
• 关键词: Surface; wave; triggering; earthquakes; non

This proposal outlines detailed analyses and modeling of surface waves in relation to triggering of both earthquakes and non-volcanic tremor. In particular, we have two main hypotheses that we will test: 1) the orientation of the local stress field and the orientation of the transient stresses induced by the surface waves combine to generate failure and 2) triggered earthquakes and triggered non-volcanic tremor exhibit similar failure mechanisms caused by transient stress fluctuations. We will test these two hypotheses by analyzing numerous large (M 7.0) earthquakes in regions with good local/regional network coverage, local/regional catalogs, and with documented triggered earthquakes and NVT. We will also develop a simple failure model that can explain our observations of triggered earthquakes and NVT. Our results will provide fundamental insight into stresses that trigger events, and whether these two seemingly different processes are indeed similar. Closely studying surface waves and triggering holds the key for understanding the physics of rupture.A growing body of scientific studies has demonstrated that the passage of transient signals, or seismic waves, from large earthquakes can remotely trigger small earthquakes and non-volcanic tremor thousands of kilometers from an epicenter of a large earthquake. These two phenomena, at first glance, appear quite different, with the only common attribute being the triggering stress: surface waves. Triggered non-volcanic tremor (NVT) is the radiation of non-impulsive seismic energy not associated with volcanic processes that occurs coincidentally with the passage of the surface waves of a larger earthquake; similarly, dynamically triggered earthquakes are generally small earthquakes that trigger coincidentally or shortly after the arrival of surface waves from a larger earthquake. Given the fact that these two triggered phenomena occur on a frequent basis, a detailed investigation into both the local and triggering, transient stress fields could provide fundamental insight into the physical mechanisms of rupture failureThis project will gain fundamental insight into dynamically triggered earthquakes and non-volcanic tremor, one of the most intriguing discoveries in earthquake science that has occurred in the past 8 years. Results of the project will be published in peer-reviewed journals and presented at national conferences to share with the scientific community. Furthermore, the University of Texas at El Paso is a Hispanic Serving Institute (HSI) and we will actively recruit undergraduate and graduate students, plus a postdoctoral scholar from underrepresented groups to participate in this project.

该提案概述了与地震和非火山震颤触发有关的表面波的详细分析和建模。 特别是，我们有两个主要的假设，我们将测试：1）局部应力场的方向和瞬态应力的方向引起的表面波联合收割机结合产生故障和2）触发地震和触发非火山震颤表现出类似的故障机制引起的瞬态应力波动。我们将通过分析具有良好的本地/区域网络覆盖、本地/区域目录以及记录的触发地震和NVT的地区中的许多大（M 7.0）地震来测试这两个假设。 我们还将开发一个简单的故障模型，可以解释我们的触发地震和NVT的观察。我们的研究结果将为触发事件的压力提供基本的见解，以及这两个看似不同的过程是否确实相似。 越来越多的科学研究表明，来自大地震的瞬态信号或地震波的通过可以远程触发距离大地震震中数千公里的小地震和非火山震颤。乍一看，这两种现象似乎完全不同，唯一的共同属性是触发应力：表面波。 触发的非火山性震颤（NVT）是与火山过程无关的非脉冲地震能量的辐射，它与较大地震的表面波的通过同时发生;类似地，动力触发的地震通常是小地震，它与较大地震的表面波的到达同时或不久后触发。 由于这两种触发现象经常发生，对局部和触发瞬态应力场的详细研究可以为破裂失效的物理机制提供基本见解。该项目将获得对动力触发地震和非火山震颤的基本见解，这是过去8年来地震科学中最有趣的发现之一。 该项目的成果将发表在同行评审的期刊上，并在国家会议上与科学界分享。此外，得克萨斯大学埃尔帕索分校是一个西班牙裔服务机构（HSI），我们将积极招募本科生和研究生，以及来自代表性不足的群体的博士后学者参加这个项目。