Collaborative Research: Constraining transient magma intrusion processes in the Nyiragongo-Kivu continental rift zone

2021年5月22日，刚果民主共和国尼拉贡戈火山南侧发生了一次破坏性极大的火山喷发，造成至少30人死亡，并在戈马市附近和市内造成重大威胁和破坏，影响到约100万人。早期的卫星图像显示，一段地下岩浆裂谷开始进一步向南裂开，越过边界进入卢旺达，破坏了房屋和农田，并在基伍湖北半部下方继续形成进一步的风险，与卢旺达和刚果民主共和国接壤。湖底的持续裂谷带来了额外的风险，导致二氧化碳的大规模快速释放，可能严重威胁到附近的人口(1986年在西非的尼奥斯湖发生的一次类似事件导致1700多人死亡)。该项目将研究2021年序列期间和之后地下岩浆运动与地震断层之间的相互作用，以帮助更好地了解裂谷作用的机制和行为，以及它们在这种环境中构成的危险。为了做到这一点，该项目将解决关键的科学问题，以更好地了解岩浆和断层随时间的演化，并深入了解控制喷发行为变化的一些关键过程。该项目将使用地球物理工具创建沿活动断层的地震活动以及岩浆物质路径的详细图像。在这里学到的地质过程将有助于理解这一事件以及未来东非和美国其他地区潜在的危险裂谷事件。通过这项提议开展的研究将资助一名肯尼亚人和两名美国卢旺达研究生以及四名卢旺达学生在东非基础研究所(EAIFR)攻读研究生课程的实地工作。与EAIFR、卢旺达大学和戈马火山观测站的研究和教育伙伴关系将有助于促进美国和中非科学家、采掘业、应急管理人员和基伍裂谷地区外交官之间的合作，并有助于为规划者提供有关自然灾害的信息。该区域的工作将有助于实时监测、危险评估和缓解，并有助于培训至少七名非洲科学家。该项目将从一群以前被监禁的妇女中招募一名杜兰大学的学生。该项目将收集详细的土地变形、地震和电磁信号信息，以检查基伍湖裂谷事件后持续变形的时间历史和程度，以及1200万年变形和岩浆堆积的累积影响。该项目将维持一个由7个全球定位系统/全球导航卫星系统站(用于土地变形测量)和9个地震仪组成的临时连续网络，其中包括在入侵事件期间安装的2个地震仪。新的和永久的地震台和25个大地电磁成像站点(电磁测量)将能够确定地壳物理性质的横向变化以及岩浆改造的程度。该项目还将收集和评估基于卫星的合成孔径雷达信息，以随着时间的推移进一步限制变形。这些数据将有助于对年轻的大陆裂谷系统的演化进行运动学和物理学建模。这些信息将有助于阐明岩浆在这些环境中的迁移过程，它们与破裂、侵入和加热的地壳的相互作用，以及它们与诱发地震活动的动力学关系。全球定位系统/全球导航卫星系统和地震网络的数据将在全球范围内提供，卢旺达的同事将能够使用软件进行快速分析，以便作出紧急反应。该项目由地球科学部的地球物理和岩石学/地球化学项目支持。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。

On 22 May 2021, a very large and destructive volcanic eruption occurred along the southern flank of Mount Nyiragongo in the Democratic Republic of Congo (DRC), killing at least 30 people and causing substantial threat and damage near and in the city of Goma, affecting approximately a million people. Early satellite imagery showed that a segment of an underground magmatic rift began opening further southward and across the border into Rwanda, damaging homes and farmland, and creating further risk as it continued below the northern half of Lake Kivu, bounding Rwanda and the DRC. Continued rifting beneath the lake presents an additional risk of causing a massive and rapid release of carbon dioxide that could gravely threaten nearby populations (a similar event in Lake Nyos in western Africa killed over 1700 people in 1986). This project will investigate the interactions between magmatic movement in the subsurface and earthquake faulting during and following the 2021 sequence to aid in developing a stronger understanding of the mechanics and behavior of rifting and the hazards they pose in such environments. To do this the project will address key scientific questions to develop a better understanding of the magmatic and faulting evolution over time and gaining insight into some of the critical processes that govern changes in eruptive behavior. The project will create detailed images of earthquake activity along active faults, as well as magmatic material pathways using geophysical tools. The geologic processes learned here will aid in understanding this and future potentially dangerous rifting events elsewhere in East-Africa and in the US. The research performed through this proposal will fund fieldwork for one Kenyan and two US-based Rwandan graduate students and four Rwanda-based students enrolled in graduate studies at the East African Institute for Fundamental Research (EAIFR). The research and educational partnerships with EAIFR, University of Rwanda, and Goma Volcano Observatory will help to foster improved collaborations between US and central-African scientists, extractive industry, emergency managers and diplomats from the Kivu rift region, and help to inform planners regarding natural hazards. The work in the region will assist with real-time monitoring, hazard assessment and mitigation, and contribute to the training of at least seven African scientists. A Tulane student will be recruited from a cohort of formerly incarcerated women.The project will collect detailed land-deformation, seismic, and electromagnetic signals information to examine the time-history and extent of continued deformation following the Lake Kivu rifting event, as well as cumulative effects of 12 million years of deformation and magmatic buildup. The project will maintain a temporary continuous network of 7 GPS/GNSS stations (for land-deformation measurement) and 9 seismometers, including 2 that were installed during the intrusion event. The new and permanent seismic stations and 25 magnetotelluric imaging sites (electromagnetic measurements) will enable determination of lateral variations in physical properties of the crust, and the degree of magmatic modification. The project too will collect and evaluate satellite-based Synthetic Aperture Radar information to further constrain deformation over time. The data will aid in kinematic and physics-based modeling of the evolution of the young continental rift system. The information gained here will help to illuminate the process of magma migration in these environments, their interaction with the fractured, intruded, and heated crust, and their dynamic relationship with induced earthquake activity. Data from the GPS/GNSS and seismic networks will be available globally, and colleagues in Rwanda will be provided with access to software for rapid analysis for emergency response. This project is supported by the Geophysics and Petrology/Geochemistry Programs in the Division of Earth Sciences.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.