The radius of the umbrella cloud helps characterize large explosive volcanic eruptions
The radius of the umbrella cloud helps characterize large explosive volcanic eruptions
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DOI：
10.1038/s43247-020-00078-3
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发表时间：
2021-01-04
影响因子：
7.9
通讯作者：
Volentik, Alain C. M.
中科院分区：
文献类型：
--
作者：
Constantinescu, Robert;Hopulele-Gligor, Aurelian;Volentik, Alain C. M.
火山学家使用喷发源参数(特别是喷发量和喷发柱高度)来评估火山危险，并对爆炸性火山喷发进行分类。由于各种因素的影响，震源参数的估计与很大的不确定性有关，这些因素包括重力散布的伞状云形成的复杂的盖菲拉沉积模式。我们修改了一个平流-扩散模型来研究这种影响。使用该模型，厄瓜多尔普鲁拉瓜2450BP喷发高潮阶段的源参数与以前的估计不同(喷发质量：1.5-5x10(11)公斤，伞状云半径：10-14公里，羽流高度：20-30公里)。我们建议更好地按体积和伞状云半径对大型爆炸性喷发进行分类，而不是仅按体积或柱子高度进行分类。在无法进行直接观测(例如卫星图像)的情况下，可以使用一个数值模型从存款数据中成功地估算出云量和伞状云半径。根据对2450年前厄瓜多尔普鲁拉瓜喷发的模拟，总喷发量和伞状云半径可以比仅凭柱子高度或体积更可靠地提供喷发特征和火山爆炸性的估计。
Eruption source parameters (in particular erupted volume and column height) are used by volcanologists to inform volcanic hazard assessments and to classify explosive volcanic eruptions. Estimations of source parameters are associated with large uncertainties due to various factors, including complex tephra sedimentation patterns from gravitationally spreading umbrella clouds. We modify an advection-diffusion model to investigate this effect. Using this model, source parameters for the climactic phase of the 2450 BP eruption of Pululagua, Ecuador, are different with respect to previous estimates (erupted mass: 1.5-5 x 10(11) kg, umbrella cloud radius: 10-14km, plume height: 20-30km). We suggest large explosive eruptions are better classified by volume and umbrella cloud radius instead of volume or column height alone. Volume and umbrella cloud radius can be successfully estimated from deposit data using one numerical model when direct observations (e.g., satellite images) are not available. Total erupted volume and umbrella cloud radius can inform estimates of eruption characteristics and volcanic explosivity more reliably than column height or volume alone, according to simulations of the eruption of Pululagua, Ecuador, 2,450 years ago.