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.

这笔用于探索性研究的小额赠款将支持南佛罗里达大学(USF)的一个科学家团队与阿根廷的一个国际火山学家小组合作旅行，这些火山学家目前正在研究智利Chaitén火山正在喷发的新火山沉积物。柴特恩火山于2008年5月2日开始喷发，显然是在经历了大约9500年的沉寂之后。这次正在进行的喷发已经是自1991年哈德逊火山喷发以来南美洲最大的一次喷发，并创造了一个独特的机会来详细采样喷发的特弗拉尘埃，特别是因为特弗拉尘埃主要向东分布，遍及整个阿根廷。来自USF的团队和他们的国际合作者计划对这一事件做出快速反应，于2008年6月和7月初在阿根廷南部采样，那里是矿床最远、最容易被侵蚀的部分。这次漂移的主要目标将是测量广泛分布的特菲拉瀑布沉积物的厚度、颗粒大小和质量负荷的变化。这些数据将能够确定喷发物质的体积；并将对目前的火山灰扩散和沉积模型进行测试。此外，他们还将与同事合作，确定与新落下的山雀花相关的易溶盐的物理和化学特征。这些数据为确定火山灰尘埃的潜在地球化学影响提供了基本信息。还计划使用主动泵送过滤器测量空气中细小火山灰(包括新落和重新悬浮)的粒度特征，这是火山灰潜在健康影响模型的基本输入。最终，他们计划使用过去十年开发的TEPHRA2数值模型来模拟柴特恩火山喷发产生的火山灰。虽然这一模型和其他尘埃模型已被广泛用于预测火山危险，但尚未有机会验证这些模型对大规模爆炸性火山喷发的有效性，这些火山喷发是在特弗拉沉积后不久直接观察和采样的。因此，Chaitén喷发提供了一个难得的机会来收集数据来验证和改进Tephra 2数值模型。例如，预测火山喷发数百公里处非常细的火山灰沉积的能力尚未得到充分测试，这将对健康和经济产生重大影响。根据现场收集的数据，该团队将使用TEPHRA2，结合非线性反演技术，估计喷发参数(柱高、持续时间、质量流量)，并与火山喷发的观测结果进行比较。所有结果将通过IAVCEI tephra工作组网站向火山学社区公布。