Powerful Silicic Explosive Volcanism: Understanding Abrupt Shifts in Eruption Style and Intensity in the 181 AD Taupo Eruption

强大的硅质爆发性火山活动：了解公元 181 年陶波火山喷发中喷发类型和强度的突变

• 批准号: 0739060
• 负责人: Bruce Houghton
• 金额: $ 28.57万
• 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: 2008
• 资助国家: 美国
• 起止时间: 2008-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0739060&HistoricalAwards=false
• 关键词: Powerful; Silicic; Explosive; Volcanism; Understanding

The 181 AD eruption of Taupo caldera was the most powerful eruption globally in at least the last 5000 years. Despite the great inertia associated with these exceptionally high eruption rates, Taupo was characterized by repeated abrupt changes in the form and power of the eruptions. Such abrupt shifts in eruptive intensity are a fundamental, yet little studied, part of many intense explosive eruptions. The causes of such shifts remain poorly understood, at a time when our models for steady state eruptive processes at volcanoes become increasingly elegant and sophisticated. The quality of hazard advice and eruption forecasts would be significantly improved if such changes could be explained, and even anticipated. The main goal of this project is to understand the mechanisms for, and origin of, such 'unsteadiness' with a long-term aim to improve preparedness for future eruptions at large volcanoes. The research plan is fourfold: a) to quantify changes in eruption intensity on a scale finer than previously described at Taupo, or for any other powerful silicic explosive eruption and constrain vent position precisely for all 7 eruptive phases/units; b) record the vesicularity (and crystallinity) of samples that span both the first order transitions in style, between units, and second order shifts in intensity; c) measure pre- and syn-eruptive volatile content of the same samples; and d) refine existing degassing, ascent and eruption models for powerful silicic eruptions with emphasis on explaining abrupt shifts in eruption processes. This project will bring together 5 students and researchers from 4 international institutions and 4 four sub-disciplines in volcanology.

公元181年的陶波火山爆发是至少在过去5000年中全球最强大的爆发。尽管这些异常高的喷发率伴随着巨大的惯性，但陶波火山的特点是喷发形式和威力的反复突变。这种爆发强度的突然变化是许多剧烈爆发的基本组成部分，但很少有人对此进行研究。这种变化的原因仍然知之甚少，在我们的火山稳态喷发过程的模型变得越来越优雅和复杂的时候。如果能够对这些变化作出解释，甚至能够预测这些变化，那么灾害咨询和火山爆发预报的质量将会大大提高。该项目的主要目标是了解这种“不稳定性”的机制和起源，长期目标是改善大型火山未来爆发的准备工作。研究计划有四个方面：a）量化喷发强度的变化，其尺度比先前在陶波描述的或任何其他强有力的大规模爆发更精细，并精确地限制所有7个喷发阶段/单元的喷口位置; B）记录泡状（和结晶度）的样品，跨越风格的第一阶过渡，单位之间，和第二阶转变的强度;（c）测量同一样品喷发前和喷发时的挥发物含量;（d）完善现有的强大的火山喷发的脱气、上升和喷发模型，重点是解释喷发过程中的突然转变。该项目将汇集来自4个国际机构和4个火山学分支学科的5名学生和研究人员。