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

2010年埃亚菲亚德拉冰盖火山爆发表明，即使是冰岛（和其他）火山的小规模爆发，全球空中交通也很脆弱。 通过运输产生的30亿美元的经济影响远远超出了区域旅客滞留的范围，影响了全球的初级和制造业。由于缺乏关键类型的数据，对火山灰浓度的预测本可以将影响降到最低。 一个关键的不足是缺乏过去火山爆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，而且是火山灰咨询中心全球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局的咨询小组合作，以确保采用结果。质量喷发率，喷发柱高度，总粒度分布（TGSD）和颗粒沉降特性，如密度和形状，是理解火山灰运输和扩散模型的关键贡献，但全球很少有火山喷发具有所有这些参数。特别缺乏TGSD数据，例如，在Mastin等人（2009年）列出的25次喷发中，柱高度、体积和喷发速率受到很好的限制，只有5次具有TGSD。我们将获得新的和汇编现有的数据，为颗粒大小和形状分布的4个Hekla喷发（2000年，1991年，1970年，H1（1104））和1875年Askja喷发的2个阶段。这些范围的喷发速度和体积超过两个数量级。三个20 - 21世纪的爆发，和Askja 1875 B，供应输入？最可能的事件的情况下，在不久的将来，喷发活动，而H1，和1875年D阶段爆发的限制？最坏的情况？十年时间尺度的情景。我们的目标是（一）了解火山碎屑的扩散和喷发率，TGSD，和火山碎屑的大小，形状，密度和结晶度之间的关系，及（ii）提供一套强大的场源参数来测试模型的火山碎屑的扩散和运输。

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.