The Fidelity of Glass Reentrants in Crystals: Witnesses of Decompression and Stalling of Magma in Conduits

由于超过5亿人（占世界人口的9%）生活在火山的最大暴露范围内，因此研究火山系统的一些最重要的问题涉及危害监测和减轻。然而，确定单个火山构成的风险类型的能力在很大程度上依赖于对其喷发产物（如浮石和火山灰）的准确解释这一具有挑战性的任务，这在历史上没有活跃过的系统中尤为重要。该项目旨在提高利用喷发产物来解释大规模爆炸性喷发如何随时间演变的能力。为了实现这一目标，将研究1991年菲律宾皮纳图博火山喷发的产物，这是20世纪观测到的最大爆发之一。通过量化与这次喷发的离散阶段相关的时间尺度，将重建控制这些剧烈事件演变的过程。这些结果将整合到从皮纳图博山收集的密集地震和视觉记录中，创建一个前所未有的数据库，将现代火山喷发监测数据与通常用于解释历史沉积物的基于实地的方法联系起来。除了这些科学影响之外，这将支持一名新的NSF PI女性，并将支持几名研究生和本科生。该项目由岩石与地球化学和促进竞争性研究的既定计划（EPSCoR）共同资助。皮纳图博火山经历了数天离散的、规模较小的次普林尼亚火山喷发，最终导致6月15日的气候喷发。通过Pinatubo火山喷发序列重建减压历史，并将这些信息与地震记录配对，可以为将通用监测技术与易于应用的岩石学工具联系起来提供显着的进步。在岩浆活动不断升级的日子里，通过测量保存在再入物（晶体中开放的融化袋）中的挥发物（H2O, CO2, Cl, Li， F）的浓度和梯度，并将这些信息与微生命生长时间尺度相结合，可以获得岩浆减压的定量记录。通过将这些方法与详细的采样相结合，将确定在爆炸活动中断期间岩浆停滞的时间和位置。进一步的信息将来自减压实验，这将允许通过模拟测试所有上升速率的解释。该项目涉及与美国地质调查局的科学家、美国境内的三所大学和菲律宾的研究人员合作。最终，该项目提供的数据集将允许我们询问是否可以看到证据，证明在爆发的产物中保存的爆发能量最终是升级的。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。

As more than 500 million people (9% of the world population) live within the maximum exposure range of a volcano, some of the most important questions for studying volcanic systems regard hazard monitoring and mitigation. However, much of the ability to define the type of risks posed by individual volcanoes relies on the challenging task of accurate interpretation of their eruptive products (e.g. pumice and ash), particularly crucial in systems that have not been historically active. This project aims to improve the ability to use eruptive products to interpret how large, explosive eruptions evolve over time. To accomplish this, the erupted products from the 1991 eruption of Mt. Pinatubo (Philippines) will be studied, one of the largest explosive eruptions observed in the 20th century. Through quantifying the timescales associated discrete phases of this eruption, the processes controlling the evolution of these violent events will be reconstructed. These results will be integrated into the dense seismic and visual records collected from Mt. Pinatubo, creating an unprecedented database for linking modern eruption monitoring data with a field-based approach typically used for interpreting historic deposits. In addition to these scientific impacts, this will support a woman who is a new NSF PI, and will support several graduate and undergraduate students. This project is jointly funded by Petrology & Geochemistry and the Established Program to Stimulate Competitive Research (EPSCoR).Mt. Pinatubo experienced several days of discrete, smaller sub-plinian explosions, which ramped up to the June 15th climatic eruption. Reconstructing the decompression history through the Mt. Pinatubo eruptive sequence, and pairing this information with the seismic record, could provide a remarkable advancement for linking a common monitoring technique with a readily applied petrographic tool. A quantitative record of magma decompression during the days of escalating activity will be obtained by measuring concentrations and gradients of volatiles (H2O, CO2, Cl, Li, F) preserved in reentrants (open melt pockets hosted in crystals) and coupling this information with microlite growth timescales. Through combining these methods with detailed sampling, an understanding for how long and where magma was stalled during breaks in explosive activity will be determined. Further information will come from decompression experiments, which will allow for testing all ascent-rate interpretations through simulations. This project involves collaborations with scientists at the United States Geological Survey, three universities within the U.S., and researchers in the Philippines. Ultimately, the dataset afforded by this project will allow us to ask whether one can see evidence for what ended up being an escalation in eruptive energy preserved within the erupted products.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.