Collaborative Research: Heterogeneities of the Alaska Megathrust: From the Overriding Plate to the Subducting Slab

合作研究：阿拉斯加巨型逆冲断层的异质性：从上覆板块到俯冲板片

• 批准号: 2330938
• 负责人: Helen Janiszewski
• 金额: $ 34.08万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-01-15 至 2026-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2330938&HistoricalAwards=false
• 关键词: Collaborative; Research; Heterogeneities; Alaska; Megathrust

Subduction, where one tectonic plate moves beneath another, can lead to large magnitude earthquakes. The Alaska Peninsula has a history of such events, making it an ideal location to explore the relationship between different geological features and these earthquakes. This project will use high-quality data from community seismic experiments to better understand the structure of the Earth's plates in this region. This will in turn allow testing hypotheses related to how structures in the overriding plate may influence earthquake processes. This research not only benefits Alaska but contributes to a global understanding of earthquake processes, ultimately helping to better prepare for and mitigate earthquake hazards at subduction zones. The broader impacts include training opportunities for graduate and undergraduate students at minority-serving institutions and support for a postdoctoral scholar.The proposed project focuses on seismic imaging of the Alaska-Aleutian subduction zone, specifically the Alaska Peninsula, to investigate the relationships between the structure of the subduction zone and megathrust earthquake properties. The study aims to enhance the understanding of factors influencing megathrust earthquakes. Utilizing data from the Alaska Amphibious Community Seismic Experiment, EarthScope Transportable Array, and USGS Alaska Earthquake Center, the research will jointly employ scattered wave and body wave tomography to obtain high-resolution constraints on the structure of the plate interface, overriding and subducting plates. The overarching goal is to test hypotheses regarding the roles of pre-existing structures in the overriding crust in megathrust earthquake processes. The canonical view of the seismogenic megathrust as a planar fault with variably locked asperities remains a useful framework, but questions persist about the specific roles of these features in seismogenesis. The research will address these uncertainties by analyzing the depth and seismic structure of the plate interface, as well as variations along dip and strike directions. Additionally, the seismic structures of the overriding and subducting plates will be examined to determine their roles in slip behaviors. By integrating scattered waves and body-wave tomography, the project aims to identify correlations between different structural features and interseismic/coseismic slips. The ultimate goal is to enhance the fundamental understanding of how geological structures influence seismic behavior, not only in Alaska but also in subduction zones worldwide, aligning with community initiatives such as Subduction Zones in 4-Dimensions (SZ4D). This project is jointly funded by the Marine Geology and Geophysics program in the Division of Ocean Sciences, the Established Program to Stimulate Competitive Research (EPSCoR), and the Geophysics program in the Division of Earth Sciences.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.

俯冲作用，即一个板块移动到另一个板块下方，可能导致大规模地震。阿拉斯加半岛历史上曾发生过此类事件，使其成为探索不同地质特征与这些地震之间关系的理想地点。该项目将使用来自社区地震实验的高质量数据，以更好地了解该地区地球板块的结构。这反过来将允许测试与覆盖板块中的结构如何影响地震过程相关的假设。这项研究不仅有利于阿拉斯加，而且有助于全球对地震过程的了解，最终有助于更好地准备和减轻俯冲带的地震灾害。更广泛的影响包括为少数族裔服务机构的研究生和本科生提供培训机会，以及为博士后学者提供支持。拟议项目的重点是阿拉斯加-阿留申俯冲带（特别是阿拉斯加半岛）的地震成像，以研究该结构之间的关系俯冲带和巨型逆冲地震特性。该研究旨在加强对影响特大逆冲地震的因素的了解。该研究将利用来自阿拉斯加两栖社区地震实验、EarthScope可移动阵列和USGS阿拉斯加地震中心的数据，联合采用散射波和体波层析成像来获得板块界面、俯冲板块和俯冲板块结构的高分辨率约束。总体目标是检验有关超级逆冲地震过程中覆盖地壳中预先存在的结构的作用的假设。将发震巨型逆冲断层视为具有可变锁定粗糙体的平面断层的经典观点仍然是一个有用的框架，但关于这些特征在地震发生中的具体作用仍然存在疑问。该研究将通过分析板块界面的深度和地震结构以及沿倾角和走向方向的变化来解决这些不确定性。此外，还将检查俯冲板块和俯冲板块的地震结构，以确定它们在滑动行为中的作用。通过整合散射波和体波断层扫描，该项目旨在识别不同结构特征与震间/同震滑移之间的相关性。最终目标是增强对地质结构如何影响阿拉斯加和全世界俯冲带地震行为的基本了解，与 4 维俯冲带 (SZ4D) 等社区倡议保持一致。该项目由海洋科学部的海洋地质和地球物理学计划、刺激竞争性研究既定计划 (EPSCoR) 以及地球科学部的地球物理学计划共同资助。该奖项反映了 NSF 的法定使命，并已被通过使用基金会的智力优点和更广泛的影响审查标准进行评估，认为值得支持。