Volcanology of Italy

The volcanism of Italy is due chiefly to the presence, a short distance to the south, of the boundary between the Eurasian Plate and the African Plate. Italy is a volcanically active country, containing the only active volcanoes in mainland Europe (while volcanic islands are also present in Greece, in the volcanic arc of the southern Aegean). The lava erupted by Italy's volcanoes is thought to result from the subduction and melting of one plate below another.

Three main clusters of volcanism exist: a line of volcanic centres running northwest along the central part of the Italian mainland (see: Campanian volcanic arc); a cluster northeast of Sicily in the Aeolian Islands; and a cluster southwest of Sicily around the island of Pantelleria, in the Mediterranean's Strait of Sicily. Sardinia has had a totally separate geological history from that of the rest of Italy, where several cycles of volcanic activity occurred, the last of which ended at the beginning of the Pleistocene, but currently hosts only permanently extinct volcanoes.

Due to their position within densely populated areas, Etna and Vesuvius have been included in the list of "Volcanoes of the Decade", a global list of volcanoes to be kept under closer surveillance. In particular, the "Volcanoes of the Decade" is a list drawn up by International Association of Volcanology and Chemistry of the Earth's Interior, as part of a United Nations project, which includes, overall, 16 volcanoes distributed all over the world.

Italy was the first country to exploit geothermal energy to produce electricity. The high geothermal gradient that forms part of the peninsula makes it potentially exploitable also in other regions; research carried out in the 1960s and 1970s identified potential geothermal fields in Lazio and Tuscany, as well as in most volcanic islands.

Volcanoes

Active volcanoes

Four of Italy's volcanoes have erupted in the last one hundred years:

* Mount Etna, on Sicily (continuous activity). It is the highest volcano in Europe west of the Caucasus.
* Stromboli, one of the Aeolian Islands (continuous activity).
* Mount Vesuvius, near Naples (last erupted in 1944); the only volcano to have recently erupted in Continental Europe.
* Vulcano, another of the Aeolian Islands, last erupted in 1888–1890.

Dormant volcanoes

At least 10 other volcanic centres have seen eruptions in historic times. In order of the most recent eruptions, they are:
* Pantelleria, off the coast of Tunisia, probably last erupted around 1,000 BC. There was a submarine eruption a few kilometres north-east of the island in 1891, which was probably related to the main volcano.
* Vulcanello, a small volcano connected by an isthmus to the island of Vulcano, which erupted out of the sea in 183 BC and showed occasional activity thereafter until the 16th century.
* Phlegraean Fields, a huge caldera containing the western area of Naples, erupted in 1538, generating the small tuff cone named Monte Nuovo ("new mountain").
* Ischia, an island 20 kilometres west of Naples, last erupted in 1302.
* Lipari, an island a couple of kilometres from Vulcano, has a volcano which last erupted in 1230.
* Vulsini (Bolsena volcano, Latera volcano, Montefiascone volcano), a caldera complex at the northern end of the Roman magmatic province (at the north of Cimini volcanic complex), last erupted in 104 BC.
* Monte Albano, a quiescent volcanic complex near Rome (south). The most recent eruptions produced Lake Nemi and Lake Albano. It may have last erupted in 5,000 BC, the idea of eruptions during the Holocene have since been questioned, and the last ascertained eruption occurred in 34,000 BC. Since this time interval is comparable to the average dormancy time of the volcano, it cannot yet be considered extinct.
* Sabatini, (Bracciano volcano and Sacrofano volcano) is a volcanic complex and caldera near Rome (north). It last erupted in 70,000 BC, but, as for the Monte Albano, it cannot yet be considered extinct.
* Cimini ( Cimino volcano and Vico volcano), a volcanic complex and caldera at the north of the Sabatini volcanic complex. It last erupted in 90,000 BC.
* Panarea, part of the Aeolian Islands, last erupted in the Pleistocene, but a high seismic and gaseous activity suggests that it can be considered quiescent.

Underwater volcanoes

In addition to the volcanoes on land, there are three submarine volcanoes in the seas surrounding Italy, in particular in the south-eastern Tyrrhenian and in the Strait of Sicily:
* Marsili, a submarine volcano in the Tyrrhenian Sea. Marsili rises 3,000 metres from the seabed in the Tyrrhenian sea 180 km south of Naples. Its summit is only 500 metres below the surface of the water. The volcano last erupted between 2,100 and 5,000 BC, and is considered active, and potentially dangerous, as a possible collapse of the volcanic building could trigger a tsunami. However, it is not yet clear how much this eventuality is actually possible, as there is no evidence of similar collapses (and consequent tsunamis) in the last 700,000 years.
* Isola Ferdinandea, emerged following a surtseyan eruption, a few kilometers north-west of Pantelleria in 1831, reaching a maximum height of 63 meters, but was eroded again at sea level after a few months. The summit is now a few meters below the surface of the sea. A later eruption may have occurred in 1863, but this is not proven. A swarm of small earthquakes in 2002 led to think that magma was moving under the volcano, but no eruption occurred. It is located in the so-called Graham volcanic field, which is believed to be, together with the nearby Terribile and Nerita fields, part of a hypothetical large underwater volcano called Empedocles. However, this hypothesis is not definitively confirmed.
* Palinuro, an underwater volcano in the Tyrrhenian Sea near the Cilento coast. It last erupted around 8,000 BC, and like the Marsili it is considered active and potentially dangerous.

Main extinct volcanoes

In Italy there is also a large number of geological structures due to extinct volcanic centres. It is possible to group these volcanoes into various categories:

* Many smaller islands belonging to the Italian Republic are of volcanic origin; the remaining Aeolian Islands (Alicudi, Filicudi, Salina) and Phlegraean Islands ( Vivara and Procida), the Cyclopean Isles, Ustica, Linosa, the Pontine Islands and Capraia.
* Lazio anti-Apennines; this area was particularly rich in volcanic activity up to the Upper Pleistocene, leaving behind a large number of volcanoes with a characteristic more or less circular shape (due to the collapse of the magma chamber): Lake Bolsena, Lake Bracciano, Lake Albano, Lake Nemi, Lake Vico. The corresponding volcanic systems are those of the Alban Hills, Monti Sabatini, Monti Cimini, Monti Volsini, and Monti della Tolfa. The first two considered dormant, the others (despite an alleged eruption of the Volsini in 104 BC) are instead considered definitively extinct.
* Still in the anti-Apennines, to the south, are the Roccamonfina (in Campania) and the Vulture, both dating back to the Pleistocene.
* To the north, in Tuscany, the Monte Amiata last erupted about 130,000 BC, and which still has a remarkable geothermal activity.
* Much older (dating back to the Oligocene) are the Euganean Hills in Veneto.
* In Valsesia (Piedmont) the remains of an ancient supervolcano were found, dating back to about 290 million years ago, long before the formation of the Alps.
* Among the volcanoes of Sardinia the main ones are Monte Arci (whose obsidian was extracted and exported in prehistoric times), Montiferru, Mount Arcuentu and the plateaus of the Giare, of a basaltic nature. These are volcanoes dating back to the period between the end of the Pliocene

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