Dike emplacement and related hazard in volcanoes with sector collapse: the 2007 Stromboli (Italy) eruption

Understanding dike propagation is fundamental for hazard mitigation. In February 2007, two effusive vents opened (at 650 and 400 m a.s.l.) along the inner flank of Sciara del Fuoco (SdF) sector collapse at Stromboli. The summit craters collapsed, obstructing the central conduit, choking the vents and increasing the deformation within SdF. Here a new vent opened (500 m a.s.l.), releasing the deformation. The eruption continued from the 400 m vent, after a summit explosion, until early April. The vents were fed by laterally propagating feeder dikes, following the maximum gravitational stresses within a cone with sector collapse. Vent location is similar to that of the 2002-2003 eruption, fed by dikes triggering landslides and tsunami. Such a dike propagation represents a constant feature of the recent Stromboli eruptions. However, this eruption did not develop catastrophic landslides, suggesting that their triggering also depends on other factors, such as the magmatic pressure.