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，许多研究人员正在对其进行深入研究。有几个项目关注大陆裂谷的后期阶段，但这项工作的目的是调查早期过程——当大陆刚刚开始分裂的时候。东非裂谷系是一个典型的大陆裂谷系，是研究大陆裂陷作用的理想场所。这个CAREER项目调查了Natron裂谷，这是位于坦桑尼亚的EARS的一部分，表达了早期的裂谷。地表下的熔融和部分熔融岩石已被证明在大陆裂谷期间对容纳断层作用起着重要作用，但活火山作用和火山管道系统的影响仍然存在争议。在纳特龙裂谷，一座活火山与纳特龙断裂并列，这是该地区主要的裂谷边界断裂。该项目将利用新的和现有的地表运动观测和计算建模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，反过来，2)推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四步计算建模方法，包括系统几何的简化模型，同一系统的基于3D物理的模型，喷发过程建模，以及检测火山异常行为的技术应用。这个职业的教育部分吸引了一系列的学生，特别是代表性不足的群体，以增加地球科学的多样性。本科培训机会将通过编码和数据分析为学生在地球科学方面的研究生学习做好准备。高中外展将影响200多名不同背景的学生。进一步加深我们对火山灾害的了解是这个项目自然产生的更广泛影响。长期以来，人们认识到大陆裂谷是通过机械拉伸和/或岩浆（包括流体）辅助过程开始的，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)阐明早期裂陷期间的火山构造过程，反过来(2)提高我们对火山喷发过程的理解。天然实验室是东非裂谷系早期裂谷纳特龙裂谷的Ol Doinyo Lengai-Natron边界断裂系统。该地区是未成熟大陆裂谷中唯一可达的火山边缘断裂系统。本研究利用全球导航卫星系统（GNSS）的开放获取数据对Ol Doinyo Lengai活火山进行观测，并通过计算建模来实现科学目标。建模组件包括使用dMODELS的简单解析正演模型、火山系统的岩浆物理模型、使用PyLith的有限元模型以及用于探测GNSS数据中潜在瞬变的反演技术。早期裂陷主要项目的结果将与有火山的中期和成熟相裂陷环境进行比较，以更好地了解早期裂陷期间火山-构造相互作用的物理特性如何与晚期大陆裂陷的演化联系起来。该奖项反映了美国国家科学基金会的法定使命，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。

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.