SGER: Extent and Impact of Distal Ash Fallout From the May 2008 Eruption of Chaiten, Chile

SGER：2008 年 5 月智利 Chaiten 喷发造成的远端火山灰沉降的范围和影响

• 批准号: 0838115
• 负责人: Charles Connor
• 金额: $ 2.62万
• 依托单位: University of South Florida
• 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: 2008-08-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0838115&HistoricalAwards=false
• 关键词: SGER; Extent; Impact; Distal; Ash

This Small Grant for Exploratory research will support the travel of a team of scientists from the University of South Florida (USF) to collaborate with an international group of volcanologists in Argentina that are currently studying the new volcanic deposits from the ongoing eruption of Chaitén volcano in Chile. Chaitén volcano began erupting on May 2, 2008, apparently after approximately 9,500 years of quiescence. This ongoing eruption is already the largest in South America since the 1991 eruption of Hudson volcano, and creates a unique opportunity to sample tephra fallout from the eruption in detail, particularly because the tephra fallout is distributed primarily eastward, across Argentina. The team from USF, together with their international collaborators, plan a rapid response to this event by sampling tephra fallout across southern Argentina, the most distal and easily eroded parts of the deposit, in June and early July, 2008. The primary goal of this excursion will be to measure the variation of thickness, grain-size, and mass loading across a widespread tephra fall deposit. Such data will allow the determination of the volume of erupted material; and will provide a test of the current models of tephra dispersal and deposition. In addition, they will work with colleagues to determine the physical and chemical characteristics of the readily-soluble salts associated with freshly-fallen tephra. Such data provide essential information for determining the potential geochemical impact of ash fallout. It is also planned to measure the grain-size characteristics of fine airborne-ash (both freshly falling, and re-suspended), using actively-pumped filters, an essential input for models of the potential health impacts of volcanic ashfall. Ultimately, they plan to use the TEPHRA2 numerical model developed over the past decade to model tephra fallout from the Chaitén eruption. Although this and other fallout models have been widely used to forecast volcano hazards there has not yet been an opportunity to validate these models for large explosive volcanic eruptions that have been directly observed and sampled soon after tephra deposition. Thus, the Chaitén eruption provides a rare opportunity to collect data to validate and improve the TEPHRA 2 numerical model. For example, the ability to forecast deposition of very fine ash hundreds of kilometers from the erupting volcano has not yet been adequately tested yet represents a major health and economic impact. With the data collected in the field, the team will use TEPHRA2, coupled with nonlinear inversion techniques, to estimate eruption parameters (column height, duration, mass flow), and compare with observations of the eruption. All results will be available to the volcanology community via the IAVCEI Tephra Working Group website.

这项用于探索性研究的小赠款将支持南佛罗里达大学（USF）的一组科学家的旅行，以与阿根廷的一组国际火山学家合作，目前正在研究智利Chaitén火山爆发中的新火山矿床。 Chaitén火山在2008年5月2日开始爆发，显然是经过大约9,500年的静止。这次持续的喷发已经是南美自1991年哈德逊火山喷发以来最大的一次，并创造了一个独特的机会，可以详细地从喷发中采样Tephra降临，尤其是因为Tephra的辐射主要分布在阿根廷各地。来自USF的团队与他们的国际合作者一起，通过对阿根廷南部的Tephra Ballout进行采样，该活动在2008年6月和7月初对Tephra Ballout进行采样，这是该活动的最远端，最容易侵蚀的部分。这次旅行的主要目标是衡量厚度，晶粒尺寸，晶状体大小，质量负载的变化，并在宽大的Tephspread tepread falled falled fall fall fall pread the。这样的数据将允许确定爆发的材料的体积；并将对当前的Tephra分散和沉积物进行测试。此外，他们将与同事合作，确定与新鲜的tephra相关的容易溶解盐的物理和化学特征。这样的数据提供了确定灰分辐射的潜在地球化学影响的重要信息。还计划使用主动泵式过滤器来测量精细机载灰分的晶粒尺寸特征（既新鲜下降，又重新悬浮），这是火山灰烬对潜在健康影响模型的重要输入。最终，他们计划使用过去十年中开发的Tephra2数值模型来对Chaitén喷发的Tephra降临。尽管这种和其他辐射模型已被广泛用于预测火山危害，但尚无机会验证这些模型是否在Tephra沉积后不久直接观察到并采样了大型爆炸性火山喷发。这，Chaitén喷发为收集数据以验证和改善Tephra 2数值模型提供了难得的机会。例如，从爆发的火山中预测非常细的灰分数百公里的能力尚未经过充分检验，但却代表了重大的健康和经济影响。通过在现场收集的数据，团队将使用Tephra2，再加上非线性反转技术，以估计喷发参数（柱高度，持续时间，质量，质量流），并与喷发的观察值进行比较。所有结果将通过IAVCEI TEPHRA工作组网站向火山学社区提供。