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，即一个构造板块在另一个板块之下移动，可能导致大震级地震。阿拉斯加半岛有过此类事件的历史，这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有关的假设。这项研究不仅使阿拉斯加受益，而且有助于全球了解地震过程，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，以及支持博士后奖学金。拟议的项目重点是阿拉斯加-阿留申俯冲带的地震成像，特别是阿拉斯加半岛，以调查俯冲带结构与大地震性质之间的关系。这项研究旨在增进对影响巨型断裂地震的因素的了解。利用阿拉斯加两栖社区地震实验、EarthScope可移动阵列和美国地质调查局阿拉斯加地震中心的数据，这项研究将联合使用散射波和体波层析成像技术，以获得对板块界面、俯冲和俯冲板块结构的高分辨率约束。首要目标是测试有关地壳中先前存在的结构在大地震过程中所起作用的假设。将孕震巨型逆冲视为具有可变闭锁的凹凸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成因中的具体作用的问题仍然存在。这项研究将通过分析板块界面的深度和地震结构，以及沿倾角和走向的变化来解决这些不确定性。此外，还将研究俯冲和俯冲板块的地震结构，以确定它们在滑动行为中的作用。通过将散射波和体波层析成像相结合，该项目旨在确定不同结构特征与地震间/同震间滑动之间的相关性。最终目标是加强对地质结构如何影响地震行为的基本理解，不仅在阿拉斯加，而且在世界各地的俯冲带，与社区倡议，如4维俯冲带(SZ4D)相一致。该项目由海洋科学部的海洋地质学和地球物理学项目、已建立的促进竞争研究计划(EPSCoR)和地球科学部的地球物理项目共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。