Phreatic eruptions at crater lakes: occurrence statistics and probabilistic hazard forecast

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• 作者：Karen Strehlow ; Laura Sandri ; Joachim H. Gottsmann…
• 关键词：Phreatic eruptions ; Ruapehu ; Probabilistic hazard assessment ; PyBetVH ; Ballistic ejecta
• 刊名：Journal of Applied Volcanology
• 出版年：2017
• 出版时间：December 2017
• 年：2017
• 卷：6
• 期：1
• 全文大小：9928KB
• 刊物主题：Geology; Geophysics/Geodesy; Natural Hazards;
• 出版者：Springer Berlin Heidelberg
• ISSN：2191-5040
• 卷排序：6

文摘

Phreatic eruptions, although posing a serious threat to people in crater proximity, are often underestimated and have been comparatively understudied. The detailed eruption catalogue for Ruapehu Volcano (New Zealand) provides an exceptional opportunity to study the statistics of recurring phreatic explosions at a crater lake volcano. We performed a statistical analysis on this phreatic eruption database, which suggests that phreatic events at Ruapehu do not follow a Poisson process. Instead they tend to cluster, which is possibly linked to an increased heat flow during periods of a more shallow-seated magma column. Larger explosions are more likely to follow shortly after smaller events, as opposed to longer periods of quiescence. The absolute probability for a phreatic explosion to occur at Ruapehu within the next month is about 10%, when averaging over the last 70 years of recording. However, the frequency of phreatic explosions is significantly higher than the background level in years prior to magmatic episodes.