Collaborative Research: Roles of rupture complexity, geological structure, stress interaction on earthquake sequences

合作研究：破裂复杂性、地质结构、应力相互作用对地震序列的作用

• 批准号: 2328485
• 负责人: Xiaowei Chen
• 金额: $ 39.94万
• 依托单位: Texas A&M University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-10-01 至 2025-09-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2328485&HistoricalAwards=false
• 关键词: Collaborative; Research; Roles; rupture; complexity

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).Earthquakes remain one of the most significant natural hazards facing society. With the increase of human-induced seismicity, regions that previously had lower seismic risk (e.g., central United States) are now facing earthquake-related hazards. The dramatic increase in the seismicity rate during the past decade in central US, and the improved instrumentation here and in California provide a rich dataset of well-recorded small-to-moderate sized earthquakes in two very different geologic settings; one dominated by tectonic motion on the great San Andreas fault, and the other where human activities induced earthquakes on less continuous, smaller, faults. This provides the opportunity to learn more about the controlling factors and consequences of earthquakes in both settings. By studying and comparing the earthquakes and their interactions in two very differently deforming regions (Northern California and Oklahoma), this project will advance our understanding of the fundamental processes of earthquake physics, their dependence on tectonic setting, and help reduce earthquake related hazards. An improvement in understanding of the relationship between earthquake rupture processes and hazard parameters (seismicity and ground motion) could help to reduce seismic hazard posed to local communities and important infrastructure. This analysis will also combine earthquake and industry 3D seismic data, which will help to develop guidelines to identify potentially hazardous critically stressed faults in Oklahoma. The project includes mentoring and collaboration on a range of levels, contributing to the education of two graduate students (at OU) and support for an early-career PI (at OU). The derived state-of-the-art database of earthquake catalog, cluster characteristics and source parameters will provide fundamental input for many studies, and will be of broad interest to earthquake hazard community, and understanding of earthquake physics. The methods and workflow will feed into activities for classes in earthquake and exploration seismology, and structural geology. The complexity of earthquakes is a significant factor governing earthquake source dynamics and the consequent ground motions, and it is related to complexity in the fault structures on which the earthquakes occur. This project will use both high-quality earthquake seismograms and industrial 3D seismic data, and develop improved techniques to quantify complexity and enhance our understanding of the fundamental earthquake source process on a variety of temporal and spatial scales. The researchers focus on the inherent earthquake source variability, its relationship with geologic structure, and its influence on earthquake sequence evolution and ground motion patterns. They perform a combined spectral and time domain analysis of earthquake sources and geological fault structure in two distinct tectonic settings: northern California which is dominated by the San Andreas plate-boundary fault, and Oklahoma where human activities are inducing earthquakes in a low-strain rate region. Spectral complexity and source-time-function complexity will be quantified, and automatic classification methods will be developed to identify complex earthquakes. Collocated high-resolution industrial 3D seismic data and seismicity enables us to better understand characteristics of seismogenic faults in the basement in detail. The synthesis and integration of multiple datasets will help to understand the interlink between geologic structure and earthquake rupture.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该奖项的全部或部分资金根据《2021 年美国救援计划法案》（公法 117-2）提供。地震仍然是社会面临的最重大的自然灾害之一。随着人为地震活动的增加，以前地震风险较低的地区（例如美国中部）现在面临与地震相关的危害。过去十年美国中部地震活动率急剧增加，以及这里和加利福尼亚州仪器设备的改进，为两种截然不同的地质环境中记录良好的中小型地震提供了丰富的数据集；一种是由圣安德烈亚斯大断层上的构造运动主导，另一种是人类活动在不太连续、较小的断层上引发地震。这提供了更多地了解这两种情况下地震的控制因素和后果的机会。通过研究和比较两个变形截然不同的地区（北加州和俄克拉荷马州）的地震及其相互作用，该项目将增进我们对地震物理基本过程及其对构造环境的依赖性的理解，并有助于减少与地震相关的危害。加深对地震破裂过程与灾害参数（地震活动和地震动）之间关系的了解有助于减少地震对当地社区和重要基础设施造成的灾害。该分析还将结合地震和工业 3D 地震数据，这将有助于制定指南来识别俄克拉荷马州潜在危险的临界应力断层。该项目包括一系列层面的指导和合作，为两名研究生（在 OU）的教育做出贡献，并为早期职业 PI（在 OU）提供支持。得出的最先进的地震目录、集群特征和震源参数数据库将为许多研究提供基础输入，并将引起地震灾害界和对地震物理学的广泛兴趣。这些方法和工作流程将纳入地震和勘探地震学以及构造地质学课程的活动中。地震的复杂性是控制震源动力学和随之而来的地震动的重要因素，它与地震发生的断层结构的复杂性有关。该项目将使用高质量地震图和工业 3D 地震数据，并开发改进的技术来量化复杂性并增强我们对各种时空尺度上基本地震源过程的理解。研究人员重点关注固有的震源变异性、其与地质结构的关系及其对地震序列演化和地面运动模式的影响。他们对两个不同构造环境中的地震源和地质断层结构进行了组合频谱和时域分析：以圣安德烈亚斯板块边界断层为主的加利福尼亚州北部，以及人类活动在低应变率下诱发地震的俄克拉荷马州地区。将量化频谱复杂性和震源时间函数复杂性，并开发自动分类方法来识别复杂地震。高分辨率工业3D地震数据和地震活动的搭配使我们能够更好地详细了解基底发震断层的特征。多个数据集的综合和整合将有助于理解地质结构与地震破裂之间的相互联系。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Influence of Fault Architecture on Induced Earthquake Sequence Evolution Revealed by High‐Resolution Focal Mechanism Solutions

• DOI: 10.1029/2022jb025040
• 发表时间: 2022-10
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: Yan Qin;Xiaowei Chen;Ting Chen;R. Abercrombie

Quantifying rupture characteristics of microearthquakes in the Parkfield Area using a high-resolution borehole network

使用高分辨率钻孔网络量化帕克菲尔德地区微地震的破裂特征

• DOI: 10.1093/gji/ggad023
• 发表时间: 2023
• 期刊: Geophysical Journal International
• 影响因子: 2.8
• 作者: Pennington, Colin N.;Wu, Qimin;Chen, Xiaowei;Abercrombie, Rachel E.
• 通讯作者: Abercrombie, Rachel E.