Coastal elevation changes in eastern Sicily: Implications for volcano instability at Mount Etna

The eastern flank of Mount Etna, Sicily has been recognized as being unstable, and three contrasting models have been proposed to account for this phenomenon, these being deep-seated spreading, shallow sliding and tectonic block movements. These models are examined by making reference to the rates and patterns of crustal movement along the eastern coastline of Sicily as determined from palaeoshoreline data. The south-eastern coastline of Sicily (Portopalo to Catania) provides no evidence of Holocene emergence. In contrast the volcanic coastline (Catania to Capo Schiso) and the northeastern shoreline (Taormina to Milazzo) display widespread evidence of coastal emergence. Radiocarbon dated remains indicate that both the volcano and northeastern Sicily have been uplifted at a rate exceeding 1.5 mm a-1 during Holocene times, although more recent rates of uplift may have been greater. The pattern of uplift suggests that the northeastern coastline of Sicily, including the volcanic edifice, is apparently uplifting as a coherent unit, with superficial flank movements being superimposed on a regionally uplifting sub-volcanic basement.