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

俯冲，即一个构造板块在另一个构造板块之下移动，可能导致大规模地震。阿拉斯加半岛有着发生此类事件的历史，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。该项目将利用社区地震实验的高质量数据，更好地了解该地区地球板块的结构。这将反过来允许测试有关如何在覆盖板块的结构可能会影响地震过程的假设。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，最终有助于更好地为俯冲带的地震灾害做好准备。更广泛的影响包括为研究生和本科生提供在少数民族服务机构的培训机会，并为一名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，以调查俯冲带结构和巨型逆冲断层地震特性之间的关系。该研究旨在提高对影响巨型逆冲断层地震的因素的认识。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，该研究将联合采用散射波和体波层析成像，以获得对板块界面结构的高分辨率约束，覆盖和俯冲板块。首要目标是测试假设的作用，在覆盖地壳中的巨型逆冲断层地震过程中预先存在的结构。典型的观点认为，孕震巨型逆冲断层是一个平面断层，具有不规则的凹凸不平，这仍然是一个有用的框架，但问题仍然存在这些功能在地震成因的具体作用。这项研究将通过分析板块界面的深度和地震结构，以及沿沿着和走向方向的变化来解决这些不确定性。此外，地震结构的覆盖和俯冲板块将被检查，以确定他们的角色在滑动行为。通过整合散射波和体波层析成像，该项目旨在确定不同结构特征与震间/同震滑动之间的相关性。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，而且在全球俯冲带，与社区倡议，如4维俯冲带（SZ 4D）保持一致。该项目由海洋科学部的海洋地质学和地球物理学项目、激励竞争性研究的既定项目（EPSCoR）和地球科学部的地球物理学项目共同资助。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。

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.