Phreatoplinian Signatures of the 1991 Explosive Eruptions of Hudson Volcano, Chile

“该奖项的资金来源是《2009 年美国复苏和再投资法案》（公法 111-5）。”许多大型火山都被冰覆盖，因此，当它们喷发时，高温岩浆和融水可能会相互作用，例如在美国的太平洋西北地区。这可能会导致灾难性洪水或爆炸活动的发生，对周边地区的社区造成重大危害。 1991年智利冰雪覆盖的哈德逊火山喷发是二十世纪最大规模的火山喷发之一。由于火山灰和洪水的广泛影响，它在阿根廷和智利造成了价值超过 850 万美元的损失。这项拟议的研究旨在以 1991 年哈德逊事件为案例研究，探讨冰川融水在影响火山喷发性质方面的潜在作用。岩浆与冰川融水的相互作用在喷发产物中产生了独特的特征，可以通过分析地球化学和扫描电子显微镜进行研究。哈德逊火山产物广泛扩散的特征表明，除了岩浆的初级脱气之外，还发生了岩浆和水的显着相互作用。因此，该研究的主要目标是尝试识别 1991 年哈德逊沉积物中岩浆/水相互作用的信号，并评估其对整体喷发的重要性。这项研究的结果对于认识大型成层火山古代沉积物中岩浆/水的相互作用具有更广泛的意义，从而有助于更精确地评​​估未来的喷发方式及其潜在的火山危害。 该研究计划包括使用 FTIR 分析 1991 年喷发的幼年颗粒的挥发物含量，以评估喷发期间停止脱气的可能性，对颗粒表面进行 SEM 成像，以寻找“湿”与“干”岩浆活动的特征，以及晶体尺寸分布分析，以评估喷发初始玄武岩阶段岩浆成分的热历史和分期历史。此外，还将进行粒度分析和浮石孔隙度测量，以评估岩浆/水相互作用对破碎效率的潜在作用。该项目将资助为期一年的博士后职位。

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)." Many large volcanoes are ice-covered and, consequently, when they erupt there is the potential for the interaction of high temperature magma and melt-water, such as in the Pacific Northwest region of the United States. This may result in the generation of catastrophic floods or explosive activity that poses significant hazards to communities in the surrounding area. The 1991 eruption of the ice-covered Hudson volcano in Chile was one of the largest explosive eruptions of the twentieth century. It caused over $8.5 million dollars worth of damage in Argentina and Chile as a result of extensive fallout of volcanic ash and flooding. This proposed research seeks to examine the potential role of glacial melt-water in affecting the nature of explosive volcanic eruptions using the 1991 Hudson event as a case study. The interaction of magma with glacial melt-water produces distinctive characteristics in the products of the eruption that can be studied by analytical geochemistry and scanning electron microscopy. Characteristics of the widespread dispersal of the Hudson volcanic products suggest that significant interactions of magma and water took place in addition to primary degassing of the magma. A principal objective of the research will thus be to try to identify the signal of magma/water interactions in the 1991 Hudson deposits and assess its importance to the overall eruption. The findings of the study should have broader significance for the recognition of magma/water interactions in the ancient deposits of large stratovolcanoes and will thus contribute to more precise assessments of future eruption styles and their potential volcanic hazards. The research plan includes the analysis of the volatile content of juvenile particles from the 1991 eruptions using FTIR to assess the potential for arrested degassing during the eruption, SEM imaging of particle surfaces to search for features of 'wet' versus 'dry' phreatomagmatic activity, and crystal size distribution analysis to evaluate the thermal and staging histories of magmatic components from the initial basaltic phase of the eruption. In addition, grain size analysis and pumice vesicularity measurements will be carried out to evaluate the potential role of magma/water interactions on fragmentation efficiency. The project will fund a one-year post-doctoral position.