CAREER: Using seismic sources to probe megathrust fault conditions

职业：利用震源探测巨型逆冲断层条件

• 批准号: 2143413
• 负责人: Wenyuan Fan
• 金额: $ 73.21万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-01 至 2027-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2143413&HistoricalAwards=false
• 关键词: CAREER; Using; seismic; sources; probe

Subduction zones, where an oceanic tectonic plate slides beneath a continental plate, host devastating earthquakes and tsunamis that put some of the world’s most densely populated coastal regions at risk. The Cascadia Subduction Zone, which extends from northern California to southwest British Columbia, produces magnitude 9 'megathrust' earthquakes every few hundred years (on an irregular schedule), and the last was over three hundred years ago. Supported by this CAREER award, Fan and his group will use over two decades of earthquake data from large arrays of seismometers to characterize properties of the Cascadia Subduction Zone fault, as well as subduction faults in Japan and Alaska. They will investigate how fault zone properties in all three locations correspond to earthquake slip behaviors, which is necessary to forecast future megathrust earthquake ruptures and their potential impacts. The research findings will be incorporated into a multi-pronged education and outreach plan combining undergraduate instruction, undergraduate and graduate student research and mentoring, and a continuous outreach project involving California high school science teachers. Megathrust slip events and faulting environments co-evolve during seismic cycles. Understanding the source processes of various slip events at subduction zones can illuminate heterogeneous stress and strength conditions along the subduction interface. Imaging fine-scale material properties can also offer insights into physical mechanisms that may regulate the development of various types of slip events. This award will investigate these two aspects simultaneously by systematically detecting, locating, and modeling very low frequency earthquakes at megathrust seismogenic patch edges, resolving finite-source attributes of small to moderate magnitude earthquakes, and imaging fault zone properties with high-frequency body wave phases. Collectively, the results will be used to track spatiotemporal evolutions of the fault zone environments and unravel the interaction and triggering processes among different slip events. The award will comparatively study three subduction zones, including the Japan, Cascadia, and Alaska subduction zones, using both onshore and offshore seismic records. The expected findings on small-scale properties might be universal to all megathrust faults, while findings on stress and strength heterogeneities could inform future hazards at Cascadia and Alaska based on the knowledge from the Japan subduction zone. The education initiative will put into place foundational and sustainable bridging activities that will establish pathways for students from underrepresented minority groups into seismology and geophysics degrees and careers.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.

俯冲带是海洋构造板块在大陆板块下方滑动的地方，这里经常发生毁灭性的地震和海啸，使世界上一些人口最稠密的沿海地区面临危险。卡斯卡迪亚俯冲带从加利福尼亚州北部延伸到不列颠哥伦比亚省西南部，每隔几百年就会发生一次 9 级“巨型逆冲”地震（时间不规律），最近一次是在三百多年前。在这一职业奖的支持下，范和他的团队将使用来自大型地震仪阵列的二十多年的地震数据来表征卡斯卡迪亚俯冲带断层以及日本和阿拉斯加俯冲断层的特性。他们将研究这三个地点的断层带特性如何与地震滑动行为相对应，这对于预测未来的巨型逆冲地震破裂及其潜在影响是必要的。研究结果将纳入一个多管齐下的教育和推广计划，结合本科生教学、本科生和研究生研究和指导，以及涉及加州高中科学教师的持续推广项目。巨型逆冲滑动事件和断层环境在地震周期中共同演化。了解俯冲带各种滑动事件的来源过程可以阐明沿俯冲界面的异质应力和强度条件。对精细材料特性进行成像还可以深入了解可能调节各种类型滑移事件发展的物理机制。该奖项将通过系统地检测、定位和模拟巨型逆冲发震斑块边缘的极低频地震，解决中小震级地震的有限源属性，以及利用高频体波相位对断层带特性进行成像，同时研究这两个方面。总的来说，这些结果将用于跟踪断层带环境的时空演化，并揭示不同滑动事件之间的相互作用和触发过程。该奖项将利用陆上和近海地震记录对三个俯冲带进行比较研究，包括日本、卡斯卡迪亚和阿拉斯加俯冲带。关于小规模属性的预期发现可能适用于所有大型逆冲断层，而关于应力和强度异质性的发现可以根据日本俯冲带的知识为卡斯卡迪亚和阿拉斯加的未来危险提供信息。该教育计划将开展基础性和可持续的衔接活动，为代表性不足的少数群体的学生建立获得地震学和地球物理学学位和职业的途径。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

A Joint Seismic and Space‐Based Investigation of the 2016 Lamplugh Glacier and 2017 Wrangell Mountains (Alaska) Landslides

• DOI: 10.1029/2022jf006903
• 发表时间: 2023-02
• 期刊: Journal of Geophysical Research: Earth Surface
• 作者: Xinyu Luo;W. Fan;Y. Fialko

In‐Situ V p / V s Reveals Fault‐Zone Material Variation at the Westernmost Gofar Transform Fault, East Pacific Rise

原位 V p / V s 揭示了东太平洋隆起最西端 Gofar 转换断层的断层带物质变化

• DOI: 10.1029/2022jb025310
• 发表时间: 2023
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: Liu, Tianze;Gong, Jianhua;Fan, Wenyuan;Lin, Guoqing
• 通讯作者: Lin, Guoqing

Seismicity, Fault Architecture, and Slip Mode of the Westernmost Gofar Transform Fault

• DOI: 10.1029/2022jb024918
• 发表时间: 2022-10
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: J. Gong;W. Fan

Very Low Frequency Earthquakes in Between the Seismogenic and Tremor Zones in Cascadia?

• DOI: 10.1029/2021av000607
• 发表时间: 2022-04-01
• 期刊: AGU ADVANCES
• 影响因子: 8.4
• 作者: Fan, Wenyuan;Barbour, Andrew J.;Okuwaki, Ryo
• 通讯作者: Okuwaki, Ryo

Combining Love and Rayleigh waves in detecting and locating seismic sources

结合洛夫波和瑞利波来检测和定位震源

• DOI: 10.1093/gji/ggad250
• 发表时间: 2023
• 期刊: Geophysical Journal International
• 影响因子: 2.8
• 作者: Fan, Wenyuan