volcano's slopes are scarred by lava flows, while the rest are heavily vegetated, with scrub and forests at higher altitudes and vineyards lower down. Formation Vesuvius is a stratovolcano and was formed as a result of the collision of two tectonic plates, the African and the Eurasian. The former was subducted at a convergent boundary beneath the latter, deeper into the earth. As the water-saturated sediments of the African oceanic plate were pushed to hotter depths inside the planet, the water boiled off and lowered the melting point of the upper mantle enough to partially melt the rocks. Because magma is less dense than the solid rock around it, it was pushed upward. Finding a weak spot at the Earth's surface, it broke through, thus forming the volcano. The volcano is one of several forming the Campanian volcanic arc. Others include Campi Flegrei, a large caldera a few kilometers to the north-west, Mount Epomeo, to the west on the island of Ischia, and several undersea volcanoes to the south. The arc forms the southern end of a larger chain of volcanoes produced by the subduction process described above, which extends northwest along the length of Italy as far as Monte Amiata in Southern Tuscany. Vesuvius is the only one to have erupted in recent history, although some of the others have erupted within the last few hundred years. Many are either extinct or have not erupted for tens of thousands of years. Eruptions Mount Vesuvius has erupted many times. Numerous others preceded the eruption in AD 79 in prehistory, including at least three significantly larger; an example is the Avellino eruption around 1800 BC, which engulfed several Bronze Age settlements. Since AD 79, the volcano has also erupted repeatedly, in 172, 203, 222, possibly in 303, 379, 472, 512, 536, 685, 787, around 860, around 900, 968, 991, 999, 1006, 1037, 1049, around 1073, 1139, 1150, and there may have been eruptions in 1270, 1347, and 1500. The volcano erupted again in 1631, six times in the 18th century (including 1779 and 1794), eight times in the 19th century (notably in 1872), and in 1906, 1929 and 1944. There have been no eruptions since 1944, and none of the eruptions after AD 79 were as large or destructive as the Pompeian one. The eruptions vary greatly in severity but are characterized by explosive outbursts of the kind dubbed Plinian after