Snow and ice perturbation during historical volcanic eruptions and the formation of lahars and floods
Snow and ice perturbation during historical volcanic eruptions and the formation of lahars and floods
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历史上火山喷发期间的冰雪扰动以及火山泥流和洪水的形成
DOI：
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发表时间：
1989
期刊：
影响因子：
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通讯作者：
C. Newhall
中科院分区：
文献类型：
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作者：
J. Major;C. Newhall
历史上的火山爆发通过扰动全世界40多座火山的冰雪而产生火山泥流和洪水。这些火山大多位于高于35°的纬度;那些在低纬度达到海拔一般超过4000米。火山事件至少可以通过五种方式扰动冰雪地幔：（1）流动的火山碎屑或热气体和火山碎屑的爆炸冲刷和融化，（2）熔岩流的表层融化，（3）冰下喷发或地热活动导致冰川冰或雪的底部融化，（4）火山口湖喷发的水喷射，以及（5）火山碎屑的沉积。在积雪火山的火山喷发的历史记录表明：（1）流动的火山碎屑碎片火山碎屑流（火山碎屑流和涌）和热气体和火山碎屑的爆炸是产生泥流和洪水的最常见的火山事件：（2）火山碎屑流通常不能足够快地融化冰雪以形成大的泥流或洪水;（3）冰下喷发或地热活动对冰川或积雪底部的加热可能导致底部融化，从而可能导致积水，并导致突然的水涌出或富含沉积物的泥石流;（4）火山灰福尔斯通常会改变冰雪的消融速率，但通常不会产生导致火山泥流和洪水形成的融水;（5）火山碎屑流、热气和火山碎屑的冲击波产生的火山泥流和洪水，或底部融化的冰雪通常有超过105立方米的体积。炽热的熔岩（火山碎屑流）在峡谷和山脊上流动。迅速聚集在盆地中，然后被迫向下。结果，在冰雪中形成了非常宽和深的通道，并产生了巨大的水流（Wolf 1878）。
Historical eruptions have produced lahars and floods by perturbing snow and ice at more than 40 volcanoes worldwide. Most of these volcanoes are located at latitudes higher than 35°; those at lower latitudes reach altitudes generally above 4000 m. Volcanic events can perturb mantles of snow and ice in at least five ways: (1) scouring and melting by flowing pyroclastic debris or blasts of hot gases and pyroclastic debris, (2) surficial melting by lava flows, (3) basal melting of glacial ice or snow by subglacial eruptions or geothermal activity, (4) ejection of water by eruptions through a crater lake, and (5) deposition of tephra fall. Historical records of volcanic eruptions at snow-clad volcanoes show the following: (1) Flowing pyroclastic debris (pyroclastic flows and surges) and blasts of hot gases and pyroclastic debris are the most common volcanic events that generate lahars and floods; (2) Surficial lava flows generally cannot melt snow and ice rapidly enough to form large lahars or floods; (3) Heating the base of a glacier or snowpack by subglacial eruptions or by geothermal activity can induce basal melting that may result in ponding of water and lead to sudden outpourings of water or sediment-rich debris flows; (4) Tephra falls usually alter ablation rates of snow and ice but generally produce little meltwater that results in the formation of lahars and floods; (5) Lahars and floods generated by flowing pyroclastic debris, blasts of hot gases and pyroclastic debris, or basal melting of snow and ice commonly have volumes that exceed 105 m3.The glowing lava (pyroclastic flow) which flowed with force over ravines and ridges...gathered in the basin quickly and then forced downwards. As a result, tremendously wide and deep pathways in the ice and snow were made and produced great streams of water (Wolf 1878).