Mount Vesuvius
Mt. Vesuvius is an Italian volcano that erupted on August 24 A.D. 79 blanketing the towns and 1000s of residents of Pompeii, Stabiae, and Herculaneum.
Mount Vesuvius is one of the world’s most dangerous volcanoes. The volcano has an eruption cycle of about 20 years, but the last eruption was in 1944.
Today two million people live in the immediate vicinity of Mount Vesuvius.
Mount Vesuvius is a strato volcano in the Gulf of Naples, Italy, about 9 kilometres (5.6 mi) east of Naples and a short distance from the shore. It is one of several volcanoes which form the Campanian volcanic arc. Vesuvius consists of a large cone partially encircled by the steep rim of a summit caldera caused by the collapse of an earlier and originally much higher structure.
Mount Vesuvius is best known for its eruption in AD 79 that led to the burying and destruction of the Roman cities of Pompeii and Herculaneum. That eruption spawned a deadly cloud of stones, ash and fumes to a height of 20.5 miles, spewing molten rock and pulverized pumice at the rate of 1.5 million tons per second, ultimately releasing a hundred thousand times the thermal energy released by the Hiroshima bombing. An estimated 16,000 people died due to hydrothermal pyroclastic flows. The only surviving eyewitness account of the event consists of two letters by Pliny the Younger to the historian Tacitus.
Vesuvius has erupted many times since and is the only volcano on the European mainland to have erupted within the last hundred years. Today, it is regarded as one of the most dangerous volcanoes in the world because of the population of 3,000,000 people living nearby and its tendency towards explosive (Plinian) eruptions. It is the most densely populated volcanic region in the world.
Vesuvius was formed as a result of the collision of two tectonic plates, the African and the Eurasian. The former was pushed beneath the latter, deeper into the earth. As the water-saturated sediments of the oceanic African plate were pushed to hotter depths in the earth, the water boiled off and caused the melting point of the upper mantle to drop enough to create partial melting of the rocks. Because magma is less dense than the solid rock around it, it was pushed upward. Finding a weak place at the Earth’s surface it broke through, producing the volcano.
The volcano is one of several which form the Campanian volcanic arc. Others include Campi Flegrei, a large caldera a few kilometres to the north west, Mount Epomeo, 20 kilometres (12 mi) 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 within 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.
Mount Vesuvius has erupted many times. The famous eruption in 79 AD was preceded by numerous others in prehistory, including at least three significantly larger ones, the best known being the Avellino eruption around 1800 BC which engulfed several Bronze Age settlements. Since 79 AD, the volcano has also erupted repeatedly, in 172, 203, 222, possibly 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, eight times in the 19th century (notably in 1872), and in 1906, 1929, and 1944. There has been no eruption since 1944, and none of the post-79 eruptions were as large or destructive as the Pompeian one.
