Parameterizing the Dynamics of Strombolian Eruptions through High-Speed Video Analysis

Strombolian explosive activity is generally characterized by a series of short, mild explosions caused by the bursting of large individual gas pockets at the magma free surface; however individual explosions at Stromboli Volcano (Italy) show how these events can be complex and heterogeneous. A new method to study the dynamics of Strombolian eruptions is proposed here, based on the acquisition and elaboration of high-speed videos at Stromboli Volcano. The analysis of high-speed videos of Strombolian explosions reveals previously unreported processes, including pre- and post- explosion crater floor deformation and multiple jet pulses within a single explosion, different explosive styles at individual vents, deformation and fragmentation of in-flight scoria clasts. Video frame elaboration allows us to measure the mass flux, velocity and exit angle of ejecta. In addition, particle velocity trends, in the light of shock tube fragmentation/ejection experiments, may provide information on the source depth of single explosion pulses. These results should be useful for future researches and may help describe quantitatively the dynamics and energetics of Strombolian eruptions, with implications on related hazard assessment