0000000001018794
AUTHOR
F. Murè
Magmatic Gas Composition Reveals the Source Depth of Slug-Driven Strombolian Explosive Activity
Strombolian-type eruptive activity, common at many volcanoes, consists of regular explosions driven by the bursting of gas slugs that rise faster than surrounding magma. Explosion quakes associated with this activity are usually localized at shallow depth; however, where and how slugs actually form remain poorly constrained. We used spectroscopic measurements performed during both quiescent degassing and explosions on Stromboli volcano (Italy) to demonstrate that gas slugs originate from as deep as the volcano-crust interface (approximately 3 kilometers), where both structural discontinuities and differential bubble-rise speed can promote slug coalescence. The observed decoupling between de…
Unusually large magmatic CO2 gas emissions prior to a basaltic paroxysm
The low-intensity activity of basaltic volcanoes is occasionally interrupted by short-lived but energetic explosions which, whilst frequently observed, are amongst the most enigmatic volcanic events in Nature. The combination of poorly understood and deep, challenging to measure, source processes make such events currently impossible to forecast. Here we report increases in quiescent degassing CO2 emissions (>10,000 t/day) prior to a powerful explosive event on Stromboli volcano on 15 March 2007. We interpret such large CO2 flux as being sourced by passive gas leakage from a deeply (>4 km) stored magma, whose depressurization, possibly caused by the onset of an effusive eruption on 28 Febru…