Deep magma mobilization years before the 2021 CE Fagradalsfjall eruption, Iceland
Deep magma mobilization years before the 2021 CE Fagradalsfjall eruption, Iceland
复制标题
2021 年冰岛 Fagradalsfjall 喷发前数年的深层岩浆流动
作者：
Kahl M
火山系统的深根对火山爆发的开始、开始和持续时间起着关键作用。在深部初始岩浆动荡和喷发触发之间的因果关系仍然很不明确。2021年，冰岛西南部Fagradalsfjall火山爆发，这是现代仪器监测的第一次在伸展脊系统上的深源喷发，为比较地球物理和岩石学数据集来探索深部岩浆动员过程提供了理想的机会。我们使用扩散计时法表明，火山系统根部的深部岩浆动荡可能比明显的地球物理喷发前兆早几年，这表明岩浆聚集和重组的早期阶段可能发生在浅层地震活动（<7 km深度）没有显著增加或大地测量变化迅速的情况下。在喷发前的几个月或几天里，地球物理和扩散年龄记录之间的密切联系标志着岩浆从初始状态过渡到开始穿越地壳的全面动员状态。我们的发现为近莫霍岩浆储存和动员的动力学提供了新的见解。通过优化监测方法来探测下地壳岩浆动荡的早期阶段，例如识别和定位深部地震活动，可以提高我们对未来火山爆发危机的反应。
The deep roots of volcanic systems play a key role in the priming, initiation, and duration of eruptions. Causative links between initial magmatic unrest at depth and eruption triggering remain poorly constrained. The 2021 CE eruption at Fagradalsfjall in southwestern Iceland, the first deep-sourced eruption on a spreading-ridge system monitored with modern instrumentation, presents an ideal opportunity for comparing geophysical and petrological data sets to explore processes of deep magma mobilization. We used diffusion chronometry to show that deep magmatic unrest in the roots of volcanic systems can precede apparent geophysical eruption precursors by years, suggesting that early phases of magma accumulation and reorganization can occur in the absence of significant increases in shallow seismicity (<7 km depth) or rapid geodetic changes. Closer correlation between geophysical and diffusion age records in the months and days prior to eruption signals the transition from a state of priming to full-scale mobilization in which magma begins to traverse the crust. Our findings provide new insights into the dynamics of near-Moho magma storage and mobilization. Monitoring approaches optimized to detect early phases of magmatic unrest in the lower crust, such as identification and location of deep seismicity, could improve our response to future eruptive crises.