EAR-PF: Towards a robust understanding of the spatio-temporal evolution of foreshock sequences from the laboratory to the field

EAR-PF：深入了解从实验室到现场的前震序列的时空演化

• 批准号: 2050006
• 负责人: David Bolton
• 金额: $ 17.4万
• 依托单位: Bolton, David Chas
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2022-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2050006&HistoricalAwards=false
• 关键词: EAR; PF; Towards; robust; understanding

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).Dr. David C. Bolton has been awarded an NSF EAR Postdoctoral Fellowship to investigate the evolution of earthquake foreshock sequences in time and space, explored through natural and laboratory fault zones. Estimating the timing and location of future earthquakes has been a long-standing goal in the study of seismology. However, progress in this area has been slow due to a poor understanding of the connections between the origins of earthquakes and seismic activity. Foreshocks are small earthquakes that precede the main earthquake and are thought to be indirect evidence that a fault is close to failure. However, foreshocks are not an easily observed feature of all earthquakes, and their connection to the impending earthquake is not well understood. This work will integrate laboratory and field-based observations of foreshocks with an aim to provide a coherent understanding of the evolution of foreshock sequences. A significant focus will be devoted to investigating whether foreshock properties encode information about the mainshock size. This work will provide key insights into the preparatory phase of earthquakes and will help advance earthquake early warning systems and improve earthquake hazard assessment. The project will also join forces with the GeoFORCE outreach program led by the Jackson School of Geosciences at UT-Austin to provide research opportunities to underrepresented communities in southwest Texas. This project will implement novel machine learning and earthquake seismology techniques for developing high-fidelity earthquake catalogs that are rich in small magnitude events. These high-resolution catalogs will illuminate how foreshocks interact with each other, their evolution in space and time, and their connection to the mainshock. The project will utilize laboratory experiments instrumented with acoustic emission monitoring to shed light on the causative processes that drive foreshock sequences. Fault zone properties such as stress, slip displacement, strain, will be integrated with the spatio-temporal patterns of acoustic emissions, allowing for a detailed understanding of the connection between the physics of earthquake nucleation processes and seismic activity. A second key element of the project will involve scaling up the laboratory observations to geologically relevant conditions by detecting and locating foreshocks on the well-characterized and seismically active Apennine fault system in Italy. This multi-scale, integrated research plan represents a unique opportunity to study seismic processes from the laboratory to tectonic scale and will determine if characteristics of laboratory foreshocks can be scaled up to tectonic fault zones. The proposed work has important implications for seismic hazard analysis and could help improve our ability to make accurate hazard forecasts and scientific predictions about earthquake processes.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.

该奖项是根据2021年美国救援计划法案（公法117-2）的全部或部分资助。博尔顿已被授予美国国家科学基金会博士后奖学金，研究地震前震序列在时间和空间上的演变，通过自然和实验室断层带进行探索。估计未来地震的时间和位置一直是地震学研究的长期目标。然而，由于对地震起源和地震活动之间的联系缺乏了解，这一领域的进展一直很缓慢。前震是在主震之前发生的小地震，被认为是断层接近破坏的间接证据。然而，前震并不是所有地震的一个容易观察到的特征，它们与即将发生的地震的联系也没有得到很好的理解。这项工作将整合前震的实验室和现场观测，目的是对前震序列的演变提供一个连贯的理解。一个重要的重点将致力于调查前震属性编码的信息，主震的大小。这项工作将为地震的准备阶段提供重要的见解，并将有助于推进地震预警系统和改进地震危险评估。 该项目还将与德州大学奥斯汀分校杰克逊地球科学学院领导的GeoFORCE外展计划联手，为德克萨斯州西南部代表性不足的社区提供研究机会。该项目将实施新的机器学习和地震学技术，以开发富含小震级事件的高保真地震目录。这些高分辨率目录将阐明前震如何相互作用，它们在空间和时间上的演变，以及它们与主震的联系。该项目将利用配备声发射监测仪器的实验室实验来阐明驱动前震序列的成因过程。断层带属性，如应力，滑动位移，应变，将与声发射的时空模式相结合，允许详细了解地震成核过程和地震活动的物理之间的联系。该项目的第二个关键要素将是通过探测和定位意大利特征明确的地震活跃的亚平宁断层系统上的前震，将实验室观测扩大到地质相关条件。这个多尺度的综合研究计划是一个独特的机会，从实验室到构造尺度研究地震过程，并将确定实验室前震的特征是否可以扩大到构造断层带。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。