CAREER: Along-Strike Variation: A Comparative Study of Subduction Zones at Multiple Scales Using Joint Receiver Function and Tomographic Inversion

俯冲带是两个构造板块汇合的地方，一个板块在另一个板块下方穿插。俯冲带在驱动板块构造方面发挥着重要作用，并承载着大地震、火山喷发、海啸和山体滑坡，其中许多对自然系统和社会都有重大影响。最近的一项研究表明，大多数俯冲带可以在250年的时间间隔内产生等于或大于8.5级的地震。俯冲地震的位置和震级受到许多因素的强烈影响，这些因素在单个俯冲带内和全球俯冲系统之间差异很大。然而，广泛观察到的变异之间的原因、影响和关系还没有被很好地理解。该职业项目的目标是用先进的地震模拟方法对五个具有代表性的俯冲带的特征有一个新的认识。大量的地球物理数据集现在为我们提供了一个很好的机会来构建俯冲系统的比较模型。通过创建高质量的俯冲系统模型，该项目将为理解基本的俯冲过程提供新的见解。该项目将涉及青年科学家在不同职业生涯早期阶段的发展，包括职业生涯初期的女地球科学家、本科生和研究生。更广泛地说，这个项目旨在为本科生开发教学工具，为K-12教育提供机会，并增加公众对潜水研究重要性的认识。这项研究的核心是三个基本问题：俯冲性质沿走向变化(分段)的规模是多少，它们从一个俯冲带到另一个俯冲带的关联程度如何？不同尺度的地幔流动如何相互作用并控制沿走向的变化，例如熔体生产力和岩浆作用？下移板块和逆冲板块的性质如何影响上地幔内的走向变化？为了充分理解分段，为了比较分段的特征和尺度，高分辨率的多个俯冲带的层析成像模型是至关重要的。该项目将使用联合接收功能(RF)和全波层析成像(FWT)来调查五个俯冲环境的结构。RFS将识别和描绘尖锐的速度不连续。先进的FWT将提供一种强有力的方法来成像地壳和上地幔的结构。RFS和FWT的结合将检测到各种地震特征。该项目的成果将有助于回答以下两个方面的问题：1)对俯冲系统中沿走向变化的类型和规模有新的认识。从地壳到上地幔的什么构造关系可以被成像，以提供对沿走向变化的洞察？细分的维度是什么？俯冲参数与沿走向变化有何关系？分段对地表构造岩浆作用的影响是什么？2)对多尺度地幔流动及其对沿走向变化的影响的关键认识。与大规模俯冲驱动过程有关的地震特征是什么？区域地质和构造过程的作用是什么？板块驱动的流动和区域对流之间的相互作用如何与分段有关？小尺度对流是否控制分段特征的间距？研究部分将得到教育和外联工作的补充，重点将是为五所大学的本科生举办夏季地震学教育讲习班。PI还将通过Girls Inc.Eureka向服务不足的8-12年级女孩介绍地球科学！程序。此外，PI将建立一个利用采用的可移动阵列地震站进行公众宣传的机制。通过综合工作，PI的目标是致力于研究、教学和推广活动，这些活动将对潜水社区和公众产生积极影响。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。

Subduction zones are where two tectonic plates converge, and one plate is thrusting beneath the other. Subduction zones play a major role in driving plate tectonics and host great earthquakes, volcanic eruptions, tsunamis, and landslides, many of which have significant impacts on natural systems and society. A recent study showed that most subduction zones can generate earthquakes with magnitude equal to or greater than 8.5 over a 250-year interval. The location and magnitude of subduction earthquakes are strongly influenced by many factors, which vary significantly within a single subduction zone and among global subduction systems. However, the causes, effects, and relationships among the widely observed variations are not well understood. The objective of the CAREER project is to develop a new understanding of the characteristics at five representative subduction zones with advanced methods of seismic modeling. A large collection of geophysical datasets now provides us with an excellent opportunity to construct comparative models of the subduction system. By creating high-quality models of subduction systems, the project will provide new insights into understanding of fundamental subduction processes. This project will involve the development of young scientists at different early career stages, including an early-career female geoscientist, undergraduate and graduate students. More broadly, this project aims to develop teaching tools for undergraduate students, to provide opportunities for K-12 education, and to increase public knowledge of the importance of subduction research. Three fundamental questions are at the core of this research: What are the scales of along-strike variations (segmentation) of subduction properties and to what degree are they correlated from one subduction zone to another? How do various scales of mantle flow interact with each other and control along-strike variation in, e.g., melt productivity and magmatism? And how do properties of the downgoing and overriding plates contribute to along-strike variation within the upper mantle? To fully understand segmentation, high-resolution tomographic models of multiple subduction zones are critically necessary in order to compare the characteristics and scales of segmentation. This project will investigate the structure of five subduction environments, using a joint receiver function (RF) and full-wave tomography (FWT). RFs will identify and delineate sharp velocity discontinuities. An advanced FWT will provide a powerful way to image the structure of the crust and upper mantle. Combination of RFs and FWT will detect a variety of seismic features. The outcomes of this project will help answer questions in the two following areas: 1) A new understanding of the types and scales of along-strike variations in subduction system. What structural correlations from crust to upper mantle can be imaged that may give insight to along-strike variations? What are the dimensions of segmentation? What are the relationships of subduction parameters with along-strike variations? What are the influences of segmentation on surface tectonomagmatism? 2) A key understanding of multi-scale mantle flow and the influences on along-strike variations. What seismic features are related to large-scale subduction-driven processes? What are the roles of regional geology and tectonic processes? How do interactions between plate-driven flow and regional convection relate to segmentation? Does small-scale convection control the spacing of segmented features? The research component will be complemented by an education and outreach effort, which will focus on developing a summer seismology education workshop for the Five-College undergraduate students. The PI will also introduce Earth science to underserved 8th-12th grade girls through the Girls Inc. Eureka! Program. Furthermore, the PI will establish a mechanism for public outreach using the adopted Transportable Array seismic station. Through the integrated work, the PI aims to devote to research, teaching, and outreach activities that will positively impact the subduction community and general public.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.