A 10-ka avalanche deposit has been discovered on the densely populated slopes of the Etna volcano in Sicily and, while regional seismicity and ground motion monitoring indicate short-term risks are small, reassessment of the danger from flank collapse is needed. Such a study would more fully document the long-term behavior of Etna and consequent long-term hazards. The discovery also seems to have finally explained the origin of Etna's Valle del Bove (VDB),the configuration of which may mitigate any danger.
New geological data place the avalanche deposit at the exit of the VDB,on the seaward, or eastern, flank of the volcano (see Figure 1). Avalanches entering the sea have the potential to generate destructive tsunamis, which cause most of the fatalities resulting from volcanic flank collapse. However, since its formation, caused by a flank collapse which left a valley with near-vertical walls, the VDB seems to have acted as a containment basin for mass flows originating in the valley.