Mechanisms and Dynamics of Magma-Water Interactions: Case Studies From Iceland

岩浆-水相互作用的机制和动力学：冰岛的案例研究

• 批准号: 1119648
• 负责人: Sarah Fagents
• 金额: $ 25万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-15 至 2015-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1119648&HistoricalAwards=false
• 关键词: Mechanisms; Dynamics; Magma; Water; Interactions

Phreatomagmatic volcanic eruptions involve interactions between magma and external water and are typically more explosive than otherwise similar magmatic eruptions that do not involve external water. Such magma-water interactions pose significant risks to society, agriculture, and the economy because they generate large volumes of fine-grained ash that can blanket nearby population centers, threaten livestock, and endanger air traffic, as demonstrated by the April 2010 and May 2011 eruptions in Iceland. Understanding the explosivity of magma-water interactions, therefore, is key to mitigating risk to society from volcanoes in wet environments. The proposed research will advance our understanding of how water enhances magma fragmentation in an explosive eruption, using a suite of case studies from Iceland in which varying amounts of water were involved. The results of this work will be disseminated broadly, through scientific publications and presentations, training of a new cadre of volcanologists, and the production of a series of short educational films designed to stimulate excitement in the processes of scientific inquiry and discovery in students of grades 9-12.Understanding explosive magma-water interactions is complicated by the fact that the magma contains gases, which, in addition to external water, participate in driving the explosivity of the eruption. It is proposed to untangle the competing influences of magmatic gases and external water by comparing the explosive products of an end member eruption type ('rootless volcanic cones'), in which no magmatic gases participate, with ash from Icelandic eruptions in which magmatic gases were involved in the fragmentation process, and with particles produced experimentally under controlled laboratory conditions. Our comparisons will involve particle shape, size, and density analysis to quantify how water affects explosivity. Computer modeling of the explosion process, incorporating particle-scale and deposit-scale measurements, will allow refinement of our understanding of the physics of magma-water interactions. With validation using our case studies, the model will ultimately be useful for predicting patterns of ash dispersal from explosive lava-water interactions. The proposed work will allow quantification of the role of external water in a way that has not previously been possible, and as a consequence, it has the potential to impact hazards assessment and mitigation strategies for such eruptions.

蒸汽岩浆火山喷发涉及岩浆和外部水之间的相互作用，并且通常比不涉及外部水的其他类似岩浆喷发更具爆炸性。这种岩浆-水的相互作用对社会、农业和经济构成了重大风险，因为它们产生大量的细颗粒火山灰，可以覆盖附近的人口中心，威胁牲畜，并危及空中交通，正如2010年4月和2011年5月冰岛火山爆发所证明的那样。因此，了解岩浆-水相互作用的爆炸性是减轻潮湿环境中火山对社会风险的关键。 拟议的研究将推进我们对水如何在爆炸性喷发中增强岩浆破碎的理解，使用冰岛的一系列案例研究，其中涉及不同数量的水。这项工作的成果将通过科学出版物和介绍、培训新的火山学家骨干以及制作一系列教育短片广泛传播，这些短片旨在激发9- 12年级学生在科学探究和发现过程中的兴奋感。此外，外部水，参与驱动喷发的爆炸性。 建议解开岩浆气体和外部水的竞争影响，通过比较的爆炸产物的端员喷发类型（'无根火山锥'），其中没有岩浆气体参与，火山灰从冰岛喷发，其中岩浆气体参与了破碎过程，并与粒子实验控制的实验室条件下产生的。 我们的比较将涉及颗粒形状，大小和密度分析，以量化水如何影响爆炸性。 爆炸过程的计算机模拟，结合粒子尺度和沉积物尺度的测量，将使我们对岩浆-水相互作用的物理学的理解更加精确。 使用我们的案例研究进行验证，该模型最终将是有用的预测模式的火山灰扩散爆炸性熔岩-水的相互作用。拟议的工作将能够以以前不可能的方式量化外部水的作用，因此，它有可能影响对这种喷发的危害评估和缓解战略。