Rapid deployment of a multi-parameter geophysical experiment at Santiaguito volcano, Guatemala, following a marked increase in explosive activity.

超过5亿人生活在活火山附近。有证据表明，在整个历史上，灾难性的火山爆发对社会造成了影响和破坏。仅在20世纪，就有近10万人死于火山爆发及其相关的危害。爆炸性的喷发将巨大的火山灰和碎屑柱注入大气层，并在火山建筑物的斜坡上释放出快速雪崩的热气和岩石。熔岩穹丘喷发代表了一种独特的兴趣，因为他们的潜在的灾难性影响的火山作用的风格。这类喷发的危险是众所周知的，因为从缓慢渗出的粘性熔岩到猛烈的爆炸活动的不可预测的转变，以及火山圆顶突然坍塌产生毁灭性的火山碎屑流的倾向。在过去的几十年里，据报道，世界各地的几个熔岩圆顶火山的喷发方式发生了变化。然而，驱动这些转变的基本过程仍然知之甚少，记录它们的地球物理测量也非常罕见。自1922年以来，危地马拉的Eschuaguito熔岩穹丘复合体一直在不断喷发，它多次在喷发和爆炸性喷发状态之间切换，甚至同时显示出两种类型的活动。在写这篇文章的时候，雷吉托正在经历一个从热情洋溢到爆炸行为的重大转变，标志着这个熔岩圆顶复杂的一些有史以来最大的喷发事件。新的活动始于2016年4月11日的一次大爆炸，产生了一个灰柱，上升到喷口上方4.5公里的高度，在卫星图像中清晰可见。当地科学家的初步估计表明，这次爆炸的能量比过去5-6年在马拉加圭托记录的任何爆炸都高出两个数量级。新的活动提供了一个难得的机会，记录和调查熔岩圆顶火山爆发风格突然转变的地球物理指纹，并破译其潜在机制。地球物理部署，包括地震、变形和声学测量，是抓住不常出现的机会的理想框架。拟议的实验将有助于解决有关熔岩圆顶火山活动的关键科学问题，并对该地区和其他易喷发地区的灾害评估和风险缓解产生影响。目标受益者范围广泛，包括学术界的科学家、民防当局、决策者和居住在活火山附近的社区。

More than 500 million people live close to active volcanoes. Evidence suggests that, throughout history, societies have been affected and destroyed by catastrophic eruptions. In the 1900s alone almost 100000 people were killed by volcanic explosions and their associated hazards. Explosive eruptions inject enormous columns of ash and debris into the atmosphere and discharge fast avalanches of hot gas and rocks on the slopes of volcanic edifices. Lava dome eruptions represent a style of volcanism of distinctive interest because of their potentially catastrophic effects. The hazards from this type of eruptions are well-known, due to the unpredictable transitions from slow effusion of viscous lava to violent explosive activity, and to the propensity of volcanic domes to suddenly collapse spawning devastating pyroclastic flows. Over the past few decades shifts in eruptive style were reported at several lava dome volcanoes worldwide. The underlying processes driving these transitions, however, remain poorly understood, and geophysical measurements documenting them are also very rare. The Santiaguito lava dome complex in Guatemala has been continuously erupting since 1922 and it has switched several times between effusive and explosive eruption regimes, even displaying the two types of activity simultaneously. At the time of this writing Santiaguito is undergoing a major transition from effusive to explosive behaviour marked by some the largest eruptive events ever recorded at this lava dome complex. The new activity started with a large explosion on 11 April, 2016, which produced an ash column that rose to a height in excess of 4.5 km above the vent and was clearly visible in satellite images. Preliminary estimates by local scientists suggest that this explosion was two orders of magnitude more energetic than anything recorded at Santiaguito over the past 5-6 years. The new activity offers a rare opportunity to document and investigate the geophysical fingerprint of a sudden switch in eruptive style at a lava dome volcano, and to decipher its underlying mechanisms. A geophysical deployment, including seismic, deformation and acoustic measurements is the ideal framework to seize an opportunity that is not frequently available. The proposed experiment will help addressing key scientific questions on activity at lava dome volcanoes, with impact on hazard assessment and risk mitigation in this and other eruption prone areas. The pool of target beneficiaries is broad and includes scientists within academia, civil defense authorities, policy makers and communities living nearby active volcanoes.