CAREER: Integration of rate-and-state friction and viscoelastic flow to model earthquake cycles on an oceanic transform fault

职业：整合速率和状态摩擦和粘弹性流来模拟海洋转换断层上的地震周期

• 批准号: 1654416
• 负责人: Meng Wei
• 金额: $ 60.16万
• 依托单位: University of Rhode Island
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2023-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1654416&HistoricalAwards=false
• 关键词: CAREER; Integration; rate; state; friction

Earthquakes are a major natural hazard threatening society around the world. For example, the southern San Andreas Fault in California is long overdue for a major earthquake that could impact more than 20 million residents in Southern California. A fundamental challenge of studying these damaging earthquakes is the long interval between large events on a given fault. Modern instruments have only captured a snapshot of the earthquake cycle on any particular fault and geologic records of past seismic behavior suffer from large uncertainty in estimates of magnitude and timing. Thus, using these limited data makes it difficult to validate models of the earthquake cycle. In contrast, many faults in the ocean have a much shorter repeat interval (~5 years) and are good analogs to continental faults like the San Andreas Fault. The repeat earthquake cycle on these oceanic faults are much better recorded. This project will use oceanic transform faults as a natural lab to study earthquake physics. This project will build a next-generation earthquake model and apply it to several well-mapped oceanic transform faults. The results will improve our understanding of how earthquakes work and will have implications for hazard assessment of the San Andreas Fault. This project will support an early career scientist and a graduate student. This project also includes comprehensive, well-integrated education and outreach activities that will benefit high school and college students and the general public. A software package that simulates earthquakes on transform faults will be shared with the scientific community through a public software repository.Oceanic transform faults are an ideal place to study earthquake cycle because of their systematic and predictable seismic behavior. The research objective of this project is to understand the fundamental spatial-temporal relationship of large earthquakes on oceanic transform faults through numerical simulations constrained by onshore and offshore earthquake observations. The current numerical models of the ocean transform earthquake cycle generally fall into one of two categories: (1) models with an elastic layer overlying a viscoelastic layer where co-seismic slip is prescribed or strain softening is used to simulate earthquakes; and (2) dynamic models based on lab-derived friction law; e.g., the rate-and-state friction, where viscoelastic flow is ignored. This project for the first time will integrate these two kinds of models and produce a next-generation dynamic model of the earthquake cycle. The project will then apply this new model to several well-mapped oceanic transform faults, such as the Gofar/Discovery fault system. The models will be enhanced via integration with an education plan that incorporates graduate, undergraduate, and high school student problem-solving and lab-based activities. The results will lead to an improved understanding of the key parameters and fundamental mechanisms that control the earthquake cycle. The goal is to transition from a conceptual understanding of the earthquake cycle toward a quantitative and predictive understanding of earthquake behavior.

地震是威胁世界社会的重大自然灾害。例如，加州南部的圣安德烈亚斯断层早就应该发生一场大地震，这可能会影响南加州2000多万居民。研究这些破坏性地震的一个基本挑战是，在一个给定的断层上，大地震之间的间隔时间很长。现代仪器只能捕捉到任何特定断层上地震周期的快照，过去地震行为的地质记录在估计震级和时间方面存在很大的不确定性。因此，使用这些有限的数据使得验证地震周期模型变得困难。相比之下，海洋中的许多断层的重复间隔要短得多（~5年），与圣安德烈亚斯断层等大陆断层很相似。这些海洋断层上的重复地震周期记录得更好。本项目将利用海洋变换断层作为研究地震物理的天然实验室。本项目将建立新一代地震模型，并将其应用于几条测绘良好的海洋转换断层。研究结果将提高我们对地震如何发生的理解，并将对圣安德烈亚斯断层的危险评估产生影响。该项目将资助一名早期职业科学家和一名研究生。该项目还包括全面的、整合良好的教育和推广活动，将使高中生、大学生和公众受益。一个在转换断层上模拟地震的软件包将通过一个公共软件库与科学界共享。海洋转换断层具有系统的、可预测的地震行为，是研究地震旋回的理想场所。本项目的研究目的是通过陆地和海上地震观测约束下的数值模拟，了解海洋转换断层大地震的基本时空关系。目前海洋变换地震周期的数值模式一般分为两类：(1)弹性层上覆粘弹性层的模式，其中规定同震滑动或使用应变软化来模拟地震；(2)基于实验室推导摩擦定律的动力学模型；例如，速率和状态摩擦，其中粘弹性流动被忽略。该项目将首次整合这两种模型，并产生下一代地震周期的动态模型。然后，该项目将把这个新模型应用于几个测绘良好的海洋转换断层，如Gofar/Discovery断层系统。这些模型将通过结合研究生、本科生和高中生解决问题和以实验室为基础的活动的教育计划而得到加强。这些结果将有助于我们更好地理解控制地震周期的关键参数和基本机制。目标是从对地震周期的概念性理解过渡到对地震行为的定量和预测性理解。

项目成果

The ubiquitous creeping segments on oceanic transform faults

• DOI: 10.1130/g49562.1
• 发表时间: 2021-11
• 期刊: Geology
• 影响因子: 5.8
• 作者: P. Shi;M. Wei;R. Pockalny

Synchronization of Earthquake Cycles of Adjacent Segments on Oceanic Transform Faults Revealed by Numerical Simulation in the Framework of Rate‐and‐State Friction

速率和状态摩擦框架下数值模拟揭示的海洋转换断层相邻段地震周期的同步性

• DOI: 10.1029/2020jb020231
• 发表时间: 2021
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: Wei, Meng;Shi, Pengcheng
• 通讯作者: Shi, Pengcheng

Numerical Modeling of Dynamically Triggered Shallow Slow Slip Events in New Zealand by the 2016 M w 7.8 Kaikoura Earthquake

2016 年 7.8 级凯库拉地震动态触发新西兰浅层慢滑事件的数值模拟

• DOI: 10.1029/2018gl077879
• 发表时间: 2018
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Wei, Meng;Kaneko, Yoshihiro;Shi, Pengcheng;Liu, Yajing
• 通讯作者: Liu, Yajing