Toward a Better Understanding of Magmatic Processes and Volcanic Hazards at Nyiragongo Volcano, DR Congo

更好地了解刚果民主共和国尼拉贡戈火山的岩浆过程和火山危害

• 批准号: 1447750
• 负责人: Kenneth Sims
• 金额: $ 26.76万
• 依托单位: University of Wyoming
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1447750&HistoricalAwards=false
• 关键词: Toward; Better; Understanding; Magmatic; Processes

Nyiragongo is a spectacular, active stratovolcano in the Virunga Volcanic Province that towers over the city of Goma, Democratic Republic of the Congo (DR Congo), and hosts the world's largest lava lake in its summit crater. Its unusual lavas are some of the least viscous on the planet and are capable of moving at velocities of up to tens of kilometers per hour. Nyiragongo is also a dangerous volcano. It looms within 20 km of the major population centers of Goma and neighboring Gisenyi Rwanda, with a combined population of at least 1 million. Destructive eruptions in 1977 and 2002 claimed many lives and devastated infrastructure in this war torn region. The next eruption could prove disastrous in this politically volatile and economically challenged area and there is consequently an urgent need to provide a concrete scientific framework for hazard assessment and risk mitigation at Nyiragongo. There is a dearth of scientific contributions that address magmatic cyclicity at this volcano and thus the primary goal of this research is to provide a temporal structure of past eruptions by age dating lava samples from Nyiragongo's main cone and from peripheral volcanic cones, which are especially dangerous because of their proximity to the population of Goma, with many cones residing within the city limits. Findings will be disseminated to the end-users, the residents of Goma and surroundings. Collaborator Dario Tedesco, who for many years has worked closely with the Goma Volcano Observatory and the United Nations addressing the volcanic hazards in the DR Congo, will facilitate this goal. In addition to this hazard assessment component, this research will focus on basic science queries about the highly unusual lavas that erupt at Nyiragongo. Not only will this study contribute to the understanding of the sources and evolution of lava flows at Nyiragongo, but it will also provide an important end-member in global studies of similar volcanic processes. For all of these reasons, this work will be supported in part by NSF's International Science and Engineering Section.The two explicit goals of this research involve 1) hazard assessment and 2) basic science questions. The primary way in which the first goal will be accomplished is through precise age dating of lava flows and parasitic cones from Nyiragongo using 40Ar/39Ar, 14C, and U decay series isotopes. A more complete temporal framework of past eruptions at Nyiragongo will be gained from these age dates from lavas collected in 2010 and critical new samples from Nyiragongo's lava flows and parasitic cones that will be collected in an ensuing field campaign. The second goal is to enhance basic scientific understanding of the sources, processes and timescales associated with the petrogenesis of the alkaline, silica-undersaturated magmatism at Nyiragongo. These results will then be compared with a separate and parallel study of Nyiragongo's highly active sister volcano Nyamulagira, as well as data from other alkaline volcanic suites around the globe. This goal will be accomplished through the measurement of major- and trace- elements, radiogenic Nd, Sr, Hf and Pb isotopes and both long- and short-lived U and Th decay series isotopes in young, known age lavas collected from Nyiragongo's lava lake in 2010.

Nyiragongo是Virunga火山省的一个壮观的，活跃的Stratovolcano，它遍布哥马市，刚果院民主共和国（刚果博士），并在其山顶火山口接待了世界上最大的熔岩湖。它的不寻常熔岩是地球上粘性最少的熔岩，能够以每小时数十公里的速度移动。 Nyiragongo也是一座危险的火山。它在戈马和邻近吉赛尼卢旺达主要人口中心的20公里内迫在眉睫，总人口至少为100万。 1977年和2002年的破坏性爆发夺走了许多生命和破坏的基础设施。在这个政治上波动和经济挑战的地区，下一次喷发可能证明是灾难性的，因此迫切需要在Nyiragongo提供一个具体的科学框架来进行危害评估和降低风险。缺乏科学贡献，可以解决这座火山上的岩浆循环性，因此，这项研究的主要目的是通过与Nyiragongo的主锥和外围火山锥的熔岩样本相结合，提供过去喷发的时间结构，这些熔岩样品尤其危险，因为它们与许多城市范围内的goma属于goma的群体，这尤其是危险的。调查结果将被传播到最终用户，戈马和周围环境的居民。多年来与戈马火山天文台和联合国紧密合作的合作者达里奥·特德斯科（Dario Tedesco）将促进这一目标。除了这种危害评估部分外，这项研究还将重点介绍有关Nyiragongo爆发的高度不寻常熔岩的基础科学疑问。这项研究不仅有助于理解Nyiragongo熔岩流的来源和演变，而且还将在全球对类似火山过程的研究中提供重要的结局。由于所有这些原因，这项工作将得到NSF的国际科学和工程部分的部分支持。这项研究的两个明确目标涉及1）危害评估和2）基础科学问题。实现第一个目标的主要方法是使用40AR/39AR，14C和U DECAY系列同位素同位素的熔岩流和寄生锥的精确年龄。从2010年收集的熔岩和Nyiragongo的熔岩流量和寄生锥的关键新样本中，将获得一个更完整的过去爆发的时间框架，并将在随后的现场活动中收集。第二个目标是增强对与Nyiragongo碱性，二氧化硅饱和岩浆作用相关的来源，过程和时间表的基本科学理解。然后将将这些结果与Nyiragongo高度活跃的姊妹火山Nyamulagira以及来自全球其他碱性火山套件的数据进行比较。该目标将通过测量主要和痕量元件，放射性元素，SR，HF和PB同位素以及2010年Nyiragongo's Lava Lake收集的年轻，已知年龄熔岩中的长和短暂的U和TH Decay系列同位素。