Ground-based InSAR reveals conduit pressurization pulses at Stromboli volcano

Stromboli volcano (Southern Italy), only few minor precur-sors (gas output) have been identified for ‘major’ Strombolianexplosions. We use ground-based interferometric syntheticaperture radar (GBInSAR) technology to monitor the displace-ment rate of the summit area of Stromboli. We analysed the2009–2011 period. The analysis of the displacement rate hasbeen performed by dividing the summit zone monitored bythe GBInSAR into three regions, corresponding to the edge ofthe crater area (1 and 2), and to the slope of the NE crater(3). Pulses of rapid expansion of sector 3, of variable durationand amplitude, appear in coincidence with periods of intenseactivity that include lava flows and major explosions. Weassociate this expansion with the pressurization of themagma column that is recharged by deep-derived gas,promoting the onset of ‘major explosion-dominated’ activity.