Vesuvius

Mount Vesuvius is a somma–stratovolcano situated on the Gulf of Naples in Campania, Italy, roughly nine kilometres east of Naples and close to the coastline. It belongs to the Campanian volcanic arc, a chain of volcanoes formed by the subduction of the African tectonic plate beneath the Eurasian plate. The volcano’s structure is distinctive: a large main cone, known as the Gran Cono, is partly surrounded by the steep rim of a summit caldera, which is the remnant of an older, much higher mountain called Monte Somma. This caldera began forming around 17,000 to 18,000 years ago and was enlarged by subsequent violent eruptions, including the catastrophic one in 79 AD. The term “somma volcano” is now used to describe any volcano with such a configuration. The highest point of the caldera rim, Punta Nasone, reaches 1,132 metres, while the summit of the Gran Cono stands at 1,281 metres above sea level, rising more than 400 metres above the floor of the Atrio di Cavallo valley. The volcano’s slopes are marked by lava flows, with scrub and forests at higher elevations and vineyards lower down.

The eruption of 79 AD ejected a towering cloud of stones, ash, and volcanic gases, releasing molten rock and pulverised pumice at an immense rate. It destroyed the Roman settlements of Pompeii, Herculaneum, Oplontis, and Stabiae, among others. More than 1,000 people are believed to have perished, though the exact number remains unknown. The only surviving eyewitness account comes from two letters written by Pliny the Younger to the historian Tacitus. Vesuvius has erupted many times since, and it is the only volcano on mainland Europe to have erupted in the last hundred years. Because approximately three million people live close enough to be affected by an eruption—with at least 600,000 in the immediate danger zone—it is considered one of the world’s most hazardous volcanoes and is classified as a Decade Volcano. Its eruptions are typically violent and explosive, a type known as Plinian.