Anisotropic imaging of the Alaska-Aleutian subduction zone from shear wave splitting analyses

通过剪切波分裂分析对阿拉斯加-阿留申俯冲带进行各向异性成像

基本信息

批准号：
1949210
负责人：
Colton Lynner
金额：
$ 22.31万
依托单位：
University of Delaware
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-08-01 至 2024-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1949210&HistoricalAwards=false
关键词：
Anisotropic imaging Alaska Aleutian subduction

项目摘要

The Alaska-Aleutians subduction zone is the most tectonically active convergent margin in North America and represents an area of both scientific and societal relevance. The region has hosted several large mega-thrust earthquakes, has a lot of volcanic activity, and has the potential of generating a tsunami. The region is also an ideal natural laboratory to study subduction systems due to the long-term subduction of the Pacific Plate, volcanism associated with subduction that builds the Aleutian Islands, and high earthquake activity. This project will examine the mantle processes that drive subduction using both onshore and offshore earthquake data. Mantle deformation will be examined within the different portions of the subduction system. The techniques to be used are complementary and when combined will provide a full picture of the subduction zone region. This integrated view will allow an investigation of the operation and interactions of the different subduction regions to create the Alaska-Aleutians subduction zone that is seen today. This project will bring an undergraduate student to the University of Delaware for a summer research experience internship and will provide training for a doctoral student. This project also will include collaborative outreach activities with the University of Delaware Disaster Research Center. This project is a multi-faceted examination of seismic anisotropy throughout the Alaska-Aleutians subduction zone (AASZ). Multiple datasets and techniques will be used in sequence to gain insights into the interactions of the different parts of the subduction system. Shear wave splitting analyses will be performed on a variety of seismic phases that are each tailored to best assess a portion of the AASZ: 1) local-S splitting at island arc stations that target the mantle wedge, 2) source-side splitting in geometries that isolate deformation within the downgoing slab, 3) source-side splitting that targets dynamics in the sub-slab mantle, and 4) traditional splitting at the ocean-bottom and onland stations. Each set of splitting observations targets a specific subduction zone region, with associated targeted questions, in such a way as to be easily integrated together. Combining the suite of complementary techniques will create a complete view of the deformation and active dynamics leading to the modern day AASZ. These results will refine the understanding of slab deformation in the mantle, the association of mantle wedge dynamics and along strike variations in arc magmatism, and the overall evolution of mantle flow beneath the Pacific as it morphs from a surface plate into a subducting slab.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.

阿拉斯加 - 亚利特人的俯冲区是北美最有活跃的融合边缘，代表了科学和社会相关性的领域。该地区举办了几次大型巨型地震，有很多火山活动，并且具有产生海啸的潜力。由于太平洋板块的长期俯冲，与建立阿留申岛岛的俯冲相关的火山和高地震活动，该地区也是研究俯冲系统的理想天然实验室。该项目将检查使用陆上和近海地震数据驱动俯冲的地幔过程。将在俯冲系统的不同部分中检查地幔变形。要使用的技术是互补的，当组合时，将提供俯冲区区域的完整图片。这种综合观点将允许对不同俯冲区域的操作和相互作用进行调查，以创建今天看到的阿拉斯加 - 亚利特人俯冲带。该项目将将一名本科生带到特拉华大学进行夏季研究经验实习，并为博士生提供培训。该项目还将包括与特拉华大学灾难研究中心的合作外展活动。该项目是整个阿拉斯加 - 亚利特人俯冲带（AASZ）的地震各向异性的多面检查。多个数据集和技术将序列使用，以了解俯冲系统不同部分的相互作用。 Shear wave splitting analyses will be performed on a variety of seismic phases that are each tailored to best assess a portion of the AASZ: 1) local-S splitting at island arc stations that target the mantle wedge, 2) source-side splitting in geometries that isolate deformation within the downgoing slab, 3) source-side splitting that targets dynamics in the sub-slab mantle, and 4) traditional splitting at the ocean-bottom和Onland车站。每组分裂观测值针对特定的俯冲区域，并具有相关的目标问题，以容易整合在一起。结合互补技术的套件将为变形和主动动态提供完整的视图，从而导致现代AASZ。这些结果将完善对地幔中平板变形的理解，地幔楔动力的关联以及弧岩岩岩的罢工变化，以及太平洋下方的地幔流的总体演变，因为它从地表板上从表面板上演变为俯冲平板。这些奖项通过评估NSF的智力及其依据，这表明了NSF的合法任务和构建，并具有良好的构建，并具有良好的支持。标准。