Disruption of Long-Term Effusive-Explosive Activity at Santiaguito, Guatemala
Disruption of Long-Term Effusive-Explosive Activity at Santiaguito, Guatemala
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DOI：
10.3389/feart.2018.00253
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发表时间：
2019-02
影响因子：
2.9
通讯作者：
O. Lamb;A. Lamur;Alejandro Díaz-Moreno;Silvio de Angelis;A. Hornby;Felix W. von Aulock;J. Kendrick;Paul A. Wallace;Ellen Gottschämmer;Andreas Rietbrock;Isaac Alvarez;G. Chigna;Y. Lavallée
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文献类型：
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作者：
O. Lamb;A. Lamur;Alejandro Díaz-Moreno;Silvio de Angelis;A. Hornby;Felix W. von Aulock;J. Kendrick;Paul A. Wallace;Ellen Gottschämmer;Andreas Rietbrock;Isaac Alvarez;G. Chigna;Y. Lavallée
要全面了解活跃火山系统的动态演化，需要大量的地球物理和地质数据，以充分约束和了解火山喷发行为的变化。危地马拉的圣地亚吉托穹顶建筑群是开口式火山系统的一个显著例子，在该系统中，持续的喷发活动历来以喷发循环和频繁的、小到中等的气体和火山灰爆炸为特征。在2015-2016年间，该火山经历了活动的迅速加剧，包括大规模的火山爆发，经常伴随着火山碎屑密度流。在这里，我们提供了圣地亚吉托2014年11月至2017年5月喷发活动的年表，该年表是根据现场观测(目测和热学)和活动报告汇编的。我们还介绍了在同一时期收集的地震和次声数据，这是迄今为止在圣地亚吉托收集的最长和最大的数据集。在研究期间发生了三个主要的喷发活动阶段。第一阶段与以前研究报告的圣地亚吉托长期喷发行为一致：熔岩同时喷发，同时发生小(无文本的1公里烟柱高度)、规则(间隔25-200分钟)、气体和火山灰爆炸。从2015年7月到2016年9月的第二阶段是以不规则间隔的大火山爆发(无烟柱高度5-7公里)定义的，通常伴随着火山碎屑密度流。第三阶段的标志是2016年10月恢复了热情洋溢的活动，其间穿插着富含天然气的小型爆炸。在研究期间，地震和次声记录了6000多起爆炸事件，清楚地描绘了火山活动的三个阶段。此外，我们还首次提出了圣地亚吉托存在爆炸冲击波和火山构造震群的地球物理证据。观测的一个重要含义是，硅质熔岩穹顶喷发的爆炸率的负趋势不能单独用作未来活动减弱和风险降低的指标。这里介绍的数据集将作为未来研究圣地亚吉托穹顶建筑群长期喷发和快速过渡到爆炸性火山活动的基础。
A comprehensive understanding of the dynamic evolution of active volcanic systems requires extensive sets of geophysical and geological data to fully constrain and understand shifts in eruptive behavior. The Santiaguito dome complex, Guatemala, is a remarkable example of an open-vent volcanic system where continuous eruptive activity has historically been characterized by cycles of effusion and frequent, small to moderate, gas-and-ash explosions. During 2015-2016 the volcano experienced a rapid intensification of activity including large vulcanian explosions, frequently accompanied by pyroclastic density currents. Here we present a chronology of the eruptive activity at Santiaguito from November 2014 - May 2017, compiled from field observations (visual and thermal) and activity reports. We also present seismic and acoustic infrasound data collected during the same period, the longest and largest dataset collected at Santiaguito to date. Three major phases of eruptive activity took place during the study period. The first phase was consistent with the long-term eruptive behavior reported at Santiaguito by previous studies: lava effusion simultaneous with small (\textless1 km plume height), regular (25-200 minute intervals), gas-and-ash explosions. The second phase from July 2015 to September 2016 was defined by large (\textless5-7 km plume height) vulcanian explosions at irregular intervals and often accompanied by pyroclastic density currents. The third phase was marked by a return to effusive activity in October 2016 interspersed by small, gas-rich explosions. Over 6000 explosive events were recorded by seismic and infrasound during the study period and clearly delineate the three phases of activity at the volcano. Furthermore, we present the first documented geophysical evidence of explosion blast waves and volcano-tectonic earthquake swarms at Santiaguito. An important implication of observations is that negative trends in explosion rates at silicic lava dome eruptions cannot be used alone as an indicator of future weaker activity and reduced risk. The dataset introduced here will serve as the foundation for future studies of the long-lived effusive eruption and rapid transitions to explosive volcanic activity at Santiaguito dome complex.