Lava flow morphology at an erupting andesitic stratovolcano: A satellite perspective on El Reventador, Ecuador
Lava flow morphology at an erupting andesitic stratovolcano: A satellite perspective on El Reventador, Ecuador
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DOI：
10.1016/j.jvolgeores.2019.01.009
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发表时间：
2019-02-15
影响因子：
2.9
通讯作者：
Mothes, P.
中科院分区：
文献类型：
--
作者：
Arnold, D. W. D.;Biggs, J.;Mothes, P.
熔岩流对靠近火山的基础设施和财产构成重大危险，了解熔岩流如何前进对于管理火山爆发期间的火山灾害是必要的。与低硅玄武岩流相比，安山岩组成的熔岩流很少喷发，因此对其特征和行为的研究相对较少。我们使用厄瓜多尔的El Reventador作为目标，在2012年2月至2016年8月的4.5年喷发期间调查安山岩熔岩流的特性。我们使用卫星雷达来绘制43个熔岩流的尺寸，并观察它们随时间推移的就位行为的变化。我们发现，流量下降的北，南翼的复仇者，大多是安置在持续时间短于卫星重复间隔24天。水流长度从0.3公里到1.7公里不等，在观测期间，水流长度普遍减少。我们测量的流量随时间的减少，与长期指数下降的渗出率，并提出这种行为是由临时岩浆存储在管道作为岩浆储层和表面之间的岩浆电容器。我们使用的尺寸流堤和宽度来估计流量屈服强度。我们观察到，一些流量被改道的地形障碍，并比较测量减少通道宽度和增加流动厚度的障碍与实验室实验的观察。雷达观测，如这里所介绍的，可以用来绘制和测量其他偏远或难以监测的火山的熔岩流场的演变特性。(C)2019作者由爱思唯尔公司出版
Lava flows pose a significant hazard to infrastructure and property located close to volcanoes, and understanding how flows advance is necessary to manage volcanic hazard during eruptions. Compared to low-silica basaltic flows, flows of andesitic composition are infrequently erupted and so relatively few studies of their characteristics and behaviour exist We use El Reventador, Ecuador as a target to investigate andesitic lava flow properties during a 4.5 year period of extrusive eruption between February 2012 and August 2016. We use satellite radar to map the dimensions of 43 lava flows and look at variations in their emplacement behaviour over time. We find that flows descended the north and south flanks of El Reventador, and were mostly emplaced over durations shorter than the satellite repeat interval of 24 days. Flows ranged in length from 0.3 to 1.7 km, and the length of flows generally decreased over the observation period. We measure a decrease in flow volume with time that is correlated with a long-term exponential decrease in effusion rate, and propose that this behaviour is caused by temporary magma storage in the conduit acting as magma capacitor between the magma reservoir and the surface. We use the dimensions of flow levees and widths to estimate the flow yield strengths. We observe that some flows were diverted by topographic obstacles, and compare measurements of decreased channel width and increased flow thickness at the obstacles with observations from laboratory experiments. Radar observations, such as those presented here, could be used to map and measure properties of evolving lava flow fields at other remote or difficult to monitor volcanoes. (C) 2019 The Authors. Published by Elsevier B.V.