Collaborative Research: Violent Basaltic Explosive Volcanism II: Constraints and Conditions of Basaltic Plinian Eruptions

合作研究：猛烈的玄武岩爆发性火山活动II：玄武岩普林尼式喷发的约束和条件

• 批准号: 0537168
• 负责人: James Gardner
• 金额: $ 10.5万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-02-01 至 2009-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0537168&HistoricalAwards=false
• 关键词: Collaborative; Research; Violent; Basaltic; Explosive

Intellectual Merit: Basaltic volcanism most commonly produces effusion of lava, mildly explosive Strombolian activity or Hawaiian fire fountain eruptions. However, some basaltic eruptions are now recognized as extremely violent, i.e. generating widespread phreatomagmatic, subplinian and Plinian fall deposits, these include historical eruptions at Kilauea (Hawaii), Etna (Italy) and Tarawera (New Zealand). These eruptions are particularly dangerous because the ascent rate of basaltic magma prior to eruption can be very high (i.e., warning times as little as a few hours) and because their precursors may be ignored or misunderstood. We set out to constrain the conditions of pre-eruptive ascent and degassing that permitted basaltic magma to erupt at Plinian intensity, principally using the example of the 122 BC eruption of Mt Etna. Mechanisms to suppress or delay open-system behavior and promote extended coupling between gas and melt are essential to permit Plinian eruptions of basaltic magma. We will look to constrain conditions and rates of magma ascent and vesiculation by performingdecompression experiments on the 122 BC Etma melt at University of Texas and comparing experimental products with natural samples, texturally and chemically. We will quantify the range of vesicle and microlite populations in the erupted scoria and experimental charges using three different techniques, to ensure reliable data sets, and to allow critical comparison of the techniques. Finally we will measure pre- and post-eruptive volatile contents of the melt phases in the same pyroclasts. Broader impacts: Our goal is to understand the mechanisms for basaltic Plinian eruptions, with a long-term aim of applying such understanding to improve preparedness for future eruptions at large basaltic volcanoes. In particular there is evidence for several large subplinian to Plinian eruptions in Etna's recent history. It is likely that another large explosive eruption will happen and affect a large population. Because the modern population surrounding Etna is much greater and the inhabited area extends farther up the volcano's flanks, future eruptions pose significant potential hazards. We will present a summary of conclusions and impacts to emergency management agencies at a workshop in Italy followed by a focused workshop for students and researchers at Etna in 2007. Our results will also be widely disseminated via the Internet using linked web sites hosted by University of Hawaii, University of Texas and INGV, Italy and in the form of a DVD in Italian and English.

知识分子的优点：玄武岩火山主义最常见的是熔岩，轻度爆炸性的斯特罗姆洛利亚活动或夏威夷消防喷泉的爆发。然而，现在一些玄武岩喷发被认为是极端暴力的，即产生广泛的phreatomagmatic，subplinian和plinian秋季沉积物，其中包括在Kilauea（Hawaii），Etna（意大利）（意大利）和Tarawera（新西兰）的历史爆发。这些爆发特别危险，因为在喷发前的玄武岩岩浆上升速度可能很高（即警告时间只有几个小时），并且由于它们的前体可能被忽略或误解。我们着手限制允许玄武岩岩浆在Plinian强度下爆发的爆发前上升和脱气条件，主要使用MT ETNA的122 BC喷发的例子。抑制或延迟开放系统行为并促进气体和熔体之间扩展耦合的机制对于允许玄武岩岩浆喷发至关重要。我们将通过在德克萨斯大学的122 BC ETMA融化上进行岩浆上升和囊泡的条件和速率来限制岩浆上升和囊泡的速度，并在质地和化学上将实验产品与天然样品进行比较。我们将使用三种不同的技术来量化爆发的Scoria和实验电荷中的囊泡和微石种群的范围，以确保可靠的数据集，并允许对技术进行严格的比较。最后，我们将测量相同的火山壳中熔体相的爆发前和爆发后的挥发性含量。更广泛的影响：我们的目标是了解玄武岩plinian喷发的机制，其长期目的是应用这种理解以改善大型玄武岩火山的未来喷发的准备。特别是有证据表明，在埃特纳（Etna）最近的历史中，有几个大型的子名单会在埃特纳（Etna）的历史中爆发。可能会发生另一次大型爆炸性喷发并影响大量人口。由于埃特纳（Etna）周围的现代人群要大得多，并且居住的地区延伸到火山的侧面，因此未来的喷发构成了巨大的潜在危害。我们将在意大利举行的研讨会上介绍结论和影响紧急管理机构的结论和影响，然后在2007年为ETNA的学生和研究人员举办了一个专注的研讨会。我们的结果还将通过夏威夷大学，德克萨斯大学和德克萨斯大学和Intaly，Italian和Italian in Italian和Ennerian in Italian和Ennerian和Ennernian和Ennernian和Ennerian和Ennerian和Ennernian和Ennerian和Ennerian和Ennerian一起通过Internet通过互联网进行广泛传播。