RUI: Collaborative Research: Testing the controls on eruption size and style at intermediate arc volcanoes: Evidence from the Holocene record at Augustine Volcano, USA

RUI：合作研究：测试对中弧火山喷发规模和类型的控制：来自美国奥古斯丁火山全新世记录的证据

• 批准号: 1948268
• 负责人: Kristina Walowski
• 金额: $ 16.48万
• 依托单位: Middlebury College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1948268&HistoricalAwards=false
• 关键词: RUI; Collaborative; Research; Testing; controls

This project is jointly funded by the Petrology and Geochemistry and the Established Program to Stimulate Competitive Research (EPSCoR) programs. Augustine Volcano in Alaska is one of the most frequently active volcanoes in the US and is considered a very high threat by the U.S. Geological Survey. The hazards posed by a volcano depend on the size and style of an eruption, and many questions remain as to what controls these eruption characteristics at intermediate arc volcanoes like Augustine. For example, are large and explosive eruptions driven by larger volumes of magma supply at shallow depths in the crust, or by faster ascent rates, or both? Prehistoric tephras (named Tephra B and Tephra M) that erupted from Augustine Volcano can provide insight into how eruptive behavior changes through time. This project has as a goal to investigate the links between magma plumbing systems and eruption explosivity. It will target two of the primary factors that determine eruption style: magma composition and the rate at which the magma ascends through the crust. Important societal benefits will emerge from this work, specifically related to volcanic hazards in the US, and that are broadly applicable to other intermediate arc volcanoes globally. Finally, this project initiates new volcano observatory-academic partnerships between the Alaska Volcano Observatory, Colgate University, and Middlebury College. This partnership will accelerate the translation of basic science to applications and monitoring that will provide active research-based curricula at two undergraduate institutions. The goals of this project are to: 1) use whole rock (pumice), phenocryst, glass, and melt inclusion geochemical data to identify the number, geometry, and relationships between the subsurface magmatic reservoirs that fed the eruptions that produced units Tephra M and Tephra B at Augustine, 2) investigate indicators of magmatic ascent rate such as volatile concentrations, crystal textures, and bubble textures within the erupted material, 3) characterize how volcanic plumbing systems evolve through time by comparing tephras B and M to historic and older prehistoric and Pleistocene deposits, and 4) investigate small-scale variability in eruption style through detailed sampling within the stratigraphy of Tephras M and B, with a targeted effort to characterize both microlite-poor and microlite-rich samples. This will resolve some of the observational bias that exists in Augustine’s record, and will help characterize the potential magnitude and importance of this bias at intermediate arc volcanoes. Data from this project will provide new constraints on the physical and chemical processes that drive ascent and explosivity and determine how magma storage reservoirs evolve over time.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.

该项目由岩石学和地球化学以及刺激竞争性研究既定计划（EPSCoR）项目共同资助。阿拉斯加的奥古斯丁火山是美国最活跃的火山之一，被美国地质调查局视为高度威胁。火山造成的危害取决于喷发的规模和类型，而对于像奥古斯丁这样的中间弧火山，这些喷发特征的控制因素仍然存在许多问题。例如，大规模的爆炸性喷发是由地壳浅层的大量岩浆供应驱动的，还是由更快的上升速度驱动的，或者两者兼而有之？从奥古斯丁火山喷发的史前火山灰（称为火山灰 B 和火山灰 M）可以让我们深入了解喷发行为如何随时间变化。该项目的目标是研究岩浆管道系统与喷发爆炸之间的联系。它将针对决定喷发类型的两个主要因素：岩浆成分和岩浆上升穿过地壳的速率。这项工作将产生重要的社会效益，特别是与美国的火山灾害相关的效益，并且广泛适用于全球其他中弧火山。最后，该项目启动了阿拉斯加火山观测站、科尔盖特大学和米德尔伯里学院之间新的火山观测站学术合作伙伴关系。这种伙伴关系将加速基础科学向应用和监测的转化，从而为两个本科院校提供积极的基于研究的课程。该项目的目标是：1) 使用整块岩石（浮石）、斑晶、玻璃和熔体包裹体地球化学数据来确定地下岩浆储层的数量、几何形状以及它们之间的关系，这些岩浆储层为奥古斯丁火山喷发产生了 Tephra M 和 Tephra B 单元，2) 研究岩浆上升速率的指标，例如挥发物浓度、晶体结构和气泡结构。 喷发物质，3) 通过将火山灰 B 和 M 与历史悠久的史前和更新世沉积物进行比较，描述火山管道系统如何随时间演化；4) 通过在火山灰 M 和 B 的地层中进行详细采样，研究喷发类型的小规模变化，并有针对性地表征贫微晶石和富含微晶石的样本。这将解决奥古斯丁记录中存在的一些观测偏差，并将有助于描述中间弧火山这种偏差的潜在规模和重要性。该项目的数据将为推动上升和爆炸的物理和化学过程提供新的约束，并确定岩浆储存库如何随时间演变。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。