Ground deformation reveals the scale-invariant conduit dynamics driving explosive basaltic eruptions
Maurizio Ripepe, Giorgio Lacanna, Marco Pistolesi, Maria Cristina Silengo, Alessandro Aiuppa, Marco Laiolo, Francesco Massimetti, Lorenzo Innocenti, Massimo Della Schiava, Marcello Bitetto, Francesco Paolo La Monica, Takeshi Nishimura, Mauro Rosi, Domenico Mangione, Antonio Ricciardi, Riccardo Genco, Diego Coppola, Emanuele Marchetti, Dario Delle Donne
Abstract
The mild activity of basaltic volcanoes is punctuated by violent explosive eruptions that occur without obvious precursors. Modelling the source processes of these sudden blasts is challenging. Here, we use two decades of ground deformation (tilt) records from Stromboli volcano to shed light, with unprecedented detail, on the short-term (minute-scale) conduit processes that drive such violent volcanic eruptions. We find that explosive eruptions, with source parameters spanning seven orders of magnitude, all share a common pre-blast ground inflation trend. We explain this exponential inflation using a model in which pressure build-up is caused by the rapid expansion of volatile-rich magma rising from depth into a shallow (<400 m) resident magma conduit. We show that the duration and amplitude of this inflation trend scales with the eruption magnitude, indicating that the explosive dynamics obey the same (scale-invariant) conduit process. This scale-invariance of pre-explosion ground deformation may usher in a new era of short-term eruption forecasting.