The ordinarily benign activity of basaltic volcanoes is periodically interrupted by violent paroxysmal explosions ranging in size from Hawaiian to Plinian in the most extreme examples. These paroxysms often occur suddenly and with limited or no precursors, leaving their causal mechanisms still incompletely understood. Two such events took place in summer 2019 at Stromboli, a volcano otherwise known for its persistent mild open-vent activity, resulting in one fatality and damage to infrastructure. Here, we use a post hoc analysis and reinterpretation of volcanic gas compositions and fluxes acquired at Stromboli to show that the two paroxysms were preceded by detectable escalations in volcanic plume CO₂ degassing weeks to months beforehand. Our results demonstrate that volcanic gas CO₂ is a key driver of explosions and that the preparatory periods ahead of explosions in basaltic systems can be captured by precursory CO₂ leakage from deeply stored mafic magma.

中文翻译：

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火山二氧化碳跟踪玄武岩发作的潜伏期

在最极端的例子中，玄武质火山通常良性的活动会周期性地被剧烈的阵发性爆炸所打断。这些发作通常是突然发生的，并且前兆有限或没有前兆，其因果机制仍未完全了解。2019 年夏天在斯特龙博利火山发生了两起此类事件，这座火山以其持续温和的开放式喷口活动而闻名，导致一人死亡和基础设施受损。在这里，我们对在 Stromboli 获得的火山气体成分和通量进行了事后分析和重新解释，以表明这两次发作之前是可检测到的火山羽状 CO ₂脱气的升级数周至数月前。我们的结果表明，火山气体 CO ₂是爆炸的关键驱动因素，并且玄武岩系统爆炸前的准备期可以通过来自深层储存的镁铁质岩浆的前驱CO _{2泄漏来捕获。}