CAREER: Volcano-Tectonic Interactions During Early Phases of Continental Rifting

大陆裂谷作用是板块构造理论的一个基本方面，目前正受到众多研究人员的广泛关注。有几个项目专注于大陆裂谷的后期阶段，但这项工作的目的是研究早期过程--当大陆刚刚开始分裂时。东非裂谷系(EAR)是典型的大陆裂谷系，是研究大陆裂谷作用的理想场所。这个职业项目研究的是纳特龙裂谷，这是居住在坦桑尼亚的耳朵的一部分，表达了早期的裂谷。地表以下熔融和部分熔融的岩石已被证明在大陆裂谷期间为断层提供了重要的便利，但活火山作用和火山管道系统的影响仍存在争议。在纳特龙裂谷，一座活火山与纳特龙断层并列，纳特龙断层是该地区主要的裂谷边界断层。该项目将利用新的和现有的地表运动观测和计算模型来解决两个基本问题：1)阐明大陆裂谷早期阶段的火山-构造相互作用，进而促进我们对火山喷发过程的理解。利用地表运动数据，将使用火山-边界断层系统的综合4步计算建模方法，其中包括系统几何模型的简化模型、同一系统的基于物理的3D模型、喷发过程建模以及检测火山异常行为的技术的应用。这一职业的教育部分吸引了一系列学生，特别是代表不足的群体，致力于增加地球科学的多样性。本科生培训机会将为学生通过编码和数据分析进行地球科学研究生学习做准备。高中外展活动将影响200多名不同背景的学生。这一项目的自然和更广泛的影响加深了我们对火山灾害的理解。长期以来，人们已经认识到大陆裂谷是通过机械拉伸和/或岩浆(包括流体)辅助的过程启动的，但火山作用在早期裂谷中的作用仍然难以捉摸。该项目的目标是解决两个关键的科学目标：(1)阐明早期裂谷期间的火山构造过程，并反过来，(2)增进我们对火山喷发过程的理解。天然实验室是纳特龙裂谷的Ol Doinyo Lengai-Natron边界断裂系统，这是东非裂谷系统的早期裂谷。该地区由一个不成熟的大陆裂谷中唯一可到达的火山边缘断层系统组成。这项研究使用来自全球导航卫星系统(GNSS)的开放访问数据来观察活火山Ol Doinyo Lengai，并使用计算模型来解决科学目标。建模部分包括使用dMODELS的简单解析正演模型、火山系统的岩浆物理模型、使用PyLith的有限元建模，以及用于检测全球导航卫星系统数据中潜在瞬变的反演技术。早期裂谷主要项目的结果将与有火山的中期和成熟阶段裂谷环境进行比较，以更好地了解早期裂谷期间火山-构造相互作用的物理学如何与后期大陆裂谷的演化联系在一起。这一奖项反映了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。

Continental rifting is a fundamental facet of plate tectonic theory and is being intensely studied by a range of researchers. Several projects focus on later stages of continental rifting, but this work aims to investigate early processes - when a continent is just beginning to break apart. The East African Rift System (EARS) is an archetype continental rift system, thus an ideal place to study continental rifting. This CAREER project investigates the Natron Rift, a part of the EARS that resides in Tanzania and expresses early phase rifting. Melted and partially molten rock beneath the surface has been shown to play an important role in accommodating faulting during continental rifting, but the influence of active volcanism and the volcanic plumbing system remains debated. In the Natron Rift, an active volcano is juxtaposed by the Natron Fault, the major rift border fault in the region. This project will tackle 2 fundamental issues using new and existing surface motion observations and computational modeling: 1) elucidating volcano-tectonic interactions during early phases of continental rifting and, in turn, 2) advancing our understanding of volcanic eruptive processes. Utilizing surface motion data, an integrated 4-step computational modeling approach of the volcano-border fault system will be used that involves simplistic models of the system’s geometry, 3D physics-based models of the same system, eruptive processes modeling, and the application of a technique that detects anomalous behavior of the volcano. The Educational component of this CAREER engages a range of students, particularly underrepresented groups, towards increasing diversity in the geosciences. An undergraduate training opportunity will prepare students for graduate studies in the geosciences trough coding and data analysis. High school outreach will impact over 200 students with diverse backgrounds. Furthering our understanding of volcanic hazards is a natural broader impact of this project.It has long been recognized that continental rifting is initiated through mechanical stretching and/or magma (including fluids)-assisted processes, but the role of volcanism during early phase rifting remains elusive. The goals of this project are to tackle 2 key scientific objectives: (1) elucidating the volcano-tectonic process during early phase rifting and, in turn, (2) advancing our understanding of volcanic eruptive processes. The natural laboratory is the Ol Doinyo Lengai-Natron Border Fault system of the Natron Rift, an early phase rift in the East African Rift System. This region comprises the only accessible volcano-border fault system in an immature continental rift. This study uses open-access data from a Global Navigation Satellite System (GNSS) to observe the active volcano Ol Doinyo Lengai and computational modeling to address the scientific objectives. Modeling components include simple analytical forward models with dMODELS, magma-physics models of the volcanic system, finite element modeling with PyLith, and an inversion technique to detect potential transients in the GNSS data. Results from the main project on early phase rifting will be compared with intermediate and mature phase rifting settings that have volcanoes to better understand how the physics of volcano-tectonic interactions during early phase rifting may be linked with the evolution of later phase continental rifting.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.