The Southern Apennines and General Geology of Mainland Southern Italy
Geologically, the area of the Southern Apennines is very young. The region is dominated by a range of fold mountains which form the backbone of the country, stretching from the Ligurian Alps in the North to Calabria in the far South (see page on the Northern Apennines also). These mountains consist mainly of white limestones, laid down in fairly shallow water during the Tertiary era. Such rocks also extend to form the jutting Sorrento Peninsula; they are well exposed in the sheer cliffs on the northern and more especially the southern coasts of the peninsula, where there are numerous features associated with typical limestone scenery.
In terms of geologic history, during and since the Tertiary era, the African Tectonic Plate has been moving northwards into the Eurasian Plate; at first, this resulted in the closing of the Tethys ocean, which lay between the two continents. Oceanic crust was subducted into the mantle beneath the Eurasian Plate; the leading edge of the Eurasian plate was then buckled and folded to form the Alps. At present, the surface boundary between the two plates is thought to lie in the south of Sicily; there is still some subduction as the final remains of the Oceanic crust continue to be pushed down in the region below Sicily and the area immediately to the north of it. This has caused andesitic “island-arc” volcanoes to form in the area of the Aeolian Islands (eg. Vulcano and Stromboli), and on the Italian mainland also.
Vesuvius is the only active volcano on the mainland, but the area to the west of Naples, the “Campi Flegrei” (Phlegrean Fields), also has numerous volcanic features, with magma thought to lie not too far below the surface. The picture is complex, with a number of fractures; Etna, on Sicily, also lies at a point where fractures intersect.
The whole of Italy is subject to the danger of earthquakes, especially in the south. A devastating earthquake, with twin epicentres inland from Naples, hit the region in 1980, killing many people and causing widespread destruction. The area is still being subjected to isostatic uplift: it is this which has created the high mountains and deep gorges of the Southern Appenines, and that is responsible also for the spectacular scenery along the coast near Sorrento and Amalfi.