Dynamics of explosive paroxysms at open-vent andesitic systems: High-resolution mass distribution analyses of the 2006 Tungurahua fall deposit (Ecuador)
Dynamics of explosive paroxysms at open-vent andesitic systems: High-resolution mass distribution analyses of the 2006 Tungurahua fall deposit (Ecuador)
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DOI：
10.1016/j.epsl.2012.11.002
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发表时间：
2013-01-01
影响因子：
5.3
通讯作者：
Yepes, Hugo
中科院分区：
文献类型：
--
作者：
Eychenne, Julia;Le Pennec, Jean-Luc;Yepes, Hugo
长期的安山岩喷发有时包括强烈的短暂爆炸事件，这可能对人口稠密地区造成重大危害。这种猛烈喷发的起源和动态仍然知之甚少，可能涉及各种不同因素。厄瓜多尔的通古拉瓦火山于1999年苏醒，是2006年8月经历了一次强烈而致命的安山质火山碎屑流形成事件的开放式喷口系统的一个例子。对矿床的检查表明，这一事件可能是由岩浆混合（火山灰中浮石和安山质火山渣共存）、岩浆-水相互作用（存在捕虏体碎屑）或深层安山质岩浆回注（基于矿物化学）引发的。在这里，我们调查这些选项进行高分辨率的质量预算分析的渣落存款。这是通过分析组件的组成和它们的质量分布模式在层中，这使我们能够记录和整合指数和幂律的质量衰减率在广泛的领域。结果得出火山灰层的总质量约为2 x 10（10）kg。浮石的质量分数太小了（
Long-lasting andesitic eruptions sometimes include strong short-lived explosive events, which can pose significant hazards in populated regions. The origin and dynamics of such violent eruptions remain poorly known and may involve a combination of different factors. Tungurahua volcano, Ecuador, reawakens in 1999 and is an example of such an open-vent system that experienced a strong and deadly andesitic pyroclastic flow-forming event in August 2006. Inspection of the deposits suggested that the event could have been triggered by magma mixing (coexistence of both silicic pumices and andesitic scoria in the tephra), magma-water interaction (presence of xenolithic clasts) or deep andesitic magma reinjection (based on mineral chemistry). Here we investigate these options by performing a high-resolution mass budget analysis of the scoria fall deposit. This is achieved by analysing componentry compositions and their mass distribution pattern in the layer, which allow us to document and integrate exponential and power laws mass decay rates over wide areas. The results yield a total mass for the tephra layer of similar to 2 x 10(10) kg. The pumice mass fraction is far too small (