Pérez Nemesio M, Padrón Eleazar, Melián Gladys, Hernández Pedro A, Padilla German, Barrancos José, Rodríguez Fátima, D'Auria Luca, Calvo David
Instituto Volcanológico de Canarias (INVOLCAN), 38400, Puerto de la Cruz, Tenerife, Canary Islands, Spain.
Environmental Research Division, ITER, 38600, Granadilla de Abona, Tenerife, Canary Islands, Spain.
Sci Rep. 2024 Apr 5;14(1):7985. doi: 10.1038/s41598-024-57666-y.
At many dormant volcanoes, magmatic gases are not channeled through preferential degassing routes as fumaroles and only percolate through the flanks of the volcano in a diffuse way. This type of volcanic gas emission provides valuable information, even though the soil matrix contains an important atmospheric component. This study aimed to demonstrate that chemical ratios such as He/CO in soil gases provide excellent information on the evolution of volcanic unrest episodes and help forecast the volcanic eruption onset. Before and during the occurrence of the October 2011-March 2012 submarine of El Hierro, Canary Islands, more than 8500 soil He analyses and diffuse CO emission measurements were performed. The results show that the soil He/CO emission ratio began increasing drastically one month before eruption onset, reaching the maximum value 10 days before. During the eruptive period, this ratio also showed a maximum value several days before the period with the highest magma emission rate. The He/CO ratio was also helpful in forecasting the eruption onset. We demonstrate that this tool can be applied in real-time during volcanic emergencies. Our results also encourage a reevaluation of the global He emission from the subaerial volcanism.
在许多休眠火山中，岩浆气体并非像火山喷气孔那样通过优先脱气路径排出，而是仅以扩散的方式渗透过火山侧翼。尽管土壤基质中含有重要的大气成分，但这种类型的火山气体排放仍能提供有价值的信息。本研究旨在证明，土壤气体中的He/CO等化学比值能为火山活动加剧阶段的演变提供极好的信息，并有助于预测火山喷发的开始。在加那利群岛耶罗岛2011年10月至2012年3月海底火山活动发生之前及期间，进行了8500多次土壤氦分析和扩散式二氧化碳排放测量。结果表明，土壤He/CO排放比值在喷发开始前一个月开始急剧上升，在喷发前10天达到最大值。在喷发期间，该比值在岩浆排放速率最高的时期之前几天也出现了最大值。He/CO比值也有助于预测喷发的开始。我们证明了该工具可在火山紧急情况期间实时应用。我们的结果还促使人们重新评估陆地火山活动的全球氦排放量。
