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

公元181年的陶波火山口喷发是至少5000年来全球最强大的一次喷发。尽管巨大的惯性与这些异常高的喷发率有关，陶波火山的特点是在喷发的形式和力量上反复突然变化。这种爆发强度的突然变化是许多剧烈爆发的基本原因，但研究却很少。当我们对火山稳态喷发过程的模型变得越来越精致和复杂时，对这种变化的原因仍然知之甚少。如果这些变化可以解释，甚至可以预测，那么危险建议和火山爆发预报的质量将大大提高。该项目的主要目标是了解这种“不稳定”的机制和起源，长期目标是提高对大型火山未来爆发的准备。研究计划有四个方面：a)量化喷发强度的变化，其规模比以前在陶波或任何其他强大的硅爆炸喷发所描述的更精细，并精确地限制所有7个喷发阶段/单位的喷口位置；B)记录样品的囊泡性（和结晶度），这些样品跨越了样式、单位之间的一级转变和强度的二级转变；C)测量同一样品爆发前和爆发时的挥发性含量；d)完善现有的脱气、上升和喷发模型，重点是解释喷发过程的突变。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。

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.