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

职业：沿走向变化：使用联合接收函数和层析反演对多尺度俯冲带进行比较研究

• 批准号: 1751974
• 负责人: Haiying Gao
• 金额: $ 52.58万
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-06-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1751974&HistoricalAwards=false
• 关键词: CAREER; Along; Strike; Variation; Comparative

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.

俯冲带是两个构造板收敛的地方，一个板在另一个板上伸出。 俯冲区在驾驶板块构造中起着重要作用，并举办了巨大的地震，火山喷发，海啸和滑坡，其中许多对自然系统和社会产生了重大影响。最近的一项研究表明，大多数俯冲带可以在250年间产生等于或大于8.5的地震。俯冲地震的位置和幅度受许多因素的强烈影响，在单个俯冲区和全球俯冲系统中，这些因素的影响很大。但是，广泛观察到的变化之间的原因，效果和关系尚不清楚。职业项目的目的是通过高级地震建模方法对五个代表性俯冲区的特征进行新的了解。现在，大量的地球物理数据集为我们提供了构建俯冲系统比较模型的绝佳机会。通过创建俯冲系统的高质量模型，该项目将为了解基本俯冲过程提供新的见解。该项目将涉及在不同职业阶段的年轻科学家的发展，包括早期的女性地球科学家，本科生和研究生。更广泛地说，该项目旨在为本科生开发教学工具，为K-12教育提供机会，并提高公众对俯冲研究重要性的了解。这项研究的核心是三个基本问题：俯冲属性的沿形变体（分段）的尺度是什么？它们从一个俯冲带到另一个程度的程度是什么？地幔流的各种尺度如何相互相互作用并控制融化生产率和岩浆性的变化？以及下层和覆盖板的性质如何促进上地幔内部的局势变化？为了充分理解分割，为了比较分割的特征和尺度，需要进行多个俯冲带的高分辨率层析成像模型。该项目将使用关节接收器函数（RF）和全波断层扫描（FWT）研究五个俯冲环境的结构。 RFS将识别并描绘出尖锐的速度不连续性。先进的FWT将提供一种强大的方式来对地壳和上地幔的结构进行图像。 RFS和FWT的组合将检测到各种地震特征。该项目的结果将有助于回答以下两个领域的问题：1）对俯冲系统中施加变化的类型和尺度的新理解。从外壳到上地幔的哪些结构相关性可以成像，从而可以洞悉沿潮流的变化？分割的尺寸是多少？俯冲参数与沿形变体的关系有什么关系？分割对表面构造的影响是什么？ 2）对多尺度地幔流的关键理解以及对沿形式变化的影响。哪些地震特征与大规模俯冲驱动的过程有关？区域地质和构造过程的作用是什么？板驱动流与区域对流之间的相互作用与分割有何关系？小规模对流是否可以控制分段特征的间距？研究组成部分将由教育和外展工作补充，该工作将着重于为五大学本科生开发夏季地震学教育研讨会。 PI还将通过女子公司尤里卡（Eureka）将地球科学介绍到服务不足的8至12年级女孩！程序。此外，PI将使用可采用的可运输阵列地震站建立公众外展的机制。通过综合工作，PI旨在致力于研究，教学和外展活动，这些活动将对俯冲社区和公众产生积极影响。该奖项反映了NSF的法定任务，并认为通过基金会的智力优点评估值得支持，并具有更广泛的影响。