Perspective sketch by Azzaro et al. (2013b) of Mount Etna, showing the volcanic edifice is sloughing off toward the southeast into the sea, activating peripheral faults such as the Fiandaca Fault, and probably also a concealed basal shear zone, marked by a set of ‘?’

Perspective sketch by Azzaro et al. (2013b) of Mount Etna, showing the volcanic edifice is sloughing off toward the southeast into the sea, activating peripheral faults such as the Fiandaca Fault, and probably also a concealed basal shear zone, marked by a set of '?'

Perspective sketch by Azzaro et al. (2013b) of Mount Etna, showing the volcanic edifice is sloughing off toward the southeast into the sea, activating peripheral faults such as the Fiandaca Fault, and probably also a concealed basal shear zone, marked by a set of ‘?’