Relationships Between Eruption Rate, Tephra Dispersal and Total Grain Size at Hekla and Askja volcanoes, Iceland: Enhancing the Source Term for Tephra Modeling

2010年Eyjafjallajökull火山的喷发表明，全球空中交通即使是冰岛(和其他)火山的小规模喷发也是脆弱的。运输带来的30亿美元经济影响远远超出了地区性旅客滞留的范围，影响到了全球的第一产业和制造业。由于缺乏关键类型的数据，本可以将影响降至最低的火山灰浓度预测受到阻碍。一个关键的不足是缺乏过去喷发的火山灰颗粒大小的分布作为预测模型的输入。目标是收集冰岛两座活火山非常年轻的喷发数据，以解决这个问题。这项研究的目标受众不仅是火山学家，还包括全球火山灰咨询中心网络的气象学家和决策者。研究人员将与来自火山灰咨询中心和气象办公室的顾问小组合作，以确保采纳这些结果。质量喷发速度、喷发柱高度、总颗粒尺寸分布(TGSD)以及颗粒沉降特性，如密度和形状，是理解火山灰传输和扩散模型的关键贡献，但在全球范围内，很少有喷发能够表征所有这些参数。TGSD数据尤其缺乏，例如，Mastin等人列出的25个喷发的柱高、体积和喷发率受到很好的限制。(2009)只有5人患有TGSD。我们将获得并汇编现有的4次Hekla喷发(2000、1991、1970、H1(1104))和1875年Askja喷发的2个阶段的颗粒大小和形状分布的新数据。这些火山喷发的速度和体积都在两个数量级以上。20-21世纪的三次喷发和Askja 1875年B喷发，为最有可能发生的事件提供了投入。情景，在不久的将来喷发活动，而H1，和1875年的D阶段喷发可信地约束？最坏的情况？十年制时间尺度的情景。我们的目标是(I)了解火山喷发速度、TGSD和火山碎屑的大小、形状、密度和结晶度之间的关系，以及(Ii)为测试火山喷发和迁移的模型提供一套可靠的场源参数。

The 2010 eruption of Eyjafjallajökull volcano demonstrated a vulnerability of global air traffic to even small eruptions from Icelandic (and other) volcanoes. The $3B economic impact via transport went well beyond the regional stranding of passengers to affect primary and manufacturing industry globally. Forecasts of ash concentrations that could have minimized the impact, were handicapped by a lack of key types of data. A key shortfall was a lack of distribution of ash particle sizes from past eruptions as input for forecasting models. the goal is to gather data from very young eruptions from two active Icelandic volcanoes to solve this problem. The target audience for this study is not merely volcanologists but meteorologists and decision makers for the global network of Volcanic Ash Advisory Centers. The researchers will work with an advisory group drawn from Volcanic Ash Advisory Centers and Meteorological Offices to ensure take-up of the results.Mass eruption rate, eruption column height, total grain size distribution (TGSD) and particle settling properties, like density and shape, are key contributions to understanding volcanic ash transport and dispersal models but globally very few eruptions are characterized for all these parameters. TGSD data is particularly lacking, e.g., of 25 eruptions with well constrained column height, volume and eruption rate listed by Mastin et al. (2009) only 5 have TGSD. We would acquire new and compile existing data for particle size and shape distributions for 4 Hekla eruptions (2000, 1991, 1970, H1 (1104)) and 2 phases of the 1875 Askja eruption. These range in eruption rate and volume over two orders of magnitude. The three 20th - 21st century eruptions, and Askja 1875 B, supply inputs to ?most plausible event? scenarios, for eruptive activity in the near future, whereas the H1, and 1875 phase D eruptions credibly constrain ?worst case? scenarios for a decadal time scale. We aim to (i) understand the relationships between tephra dispersal and eruption rate, TGSD, and pyroclast size, shape, density and crystallinity, and (ii) supply a set of robust field-derived source parameters to test models of tephra dispersal and transport.