| Phlegraean Fields | |
|---|---|
View of the Phlegraean Fields from the Hermitage of Camaldoli in Naples | |
| Highest point | |
| Elevation | 458 m (1,503 ft) |
| Coordinates | 40°49′37″N 14°08′20″E / 40.827°N 14.139°E |
| Geography | |
| Location | Metropolitan City of Naples, Campania, Italy |
| Geology | |
| Age of rock | 40,000 years |
| Mountain type | Caldera |
| Volcanic arc/belt | Campanian volcanic arc |
| Last eruption | 29 September to 6 October 1538 |




The Phlegraean Fields (Italian: Campi Flegrei, Italian: [ˈkampi fleˈɡrɛːi]; Neapolitan: Campe Flegree) is a large dormant caldera volcano and a supervolcano in the region of Campania, Italy, which lies immediately west of Naples, in the northwestern corner of the Gulf of Naples. The Phlegraean Fields caldera has a total of 24 volcanic craters and half of the caldera lies under the Gulf of Naples. It has a diameter of around 12 km × 15 km and has an area of 100 km².
It is located in a densely populated area with high volcanic activity and lies about 20 km west of the dormant volcano Mount Vesuvius. The city of Naples is located between the two volcanoes. Both the Phlegraean Fields and Mount Vesuvius are part of the Campanian volcanic arc, a volcanic arc (group of volcanoes), which include a number of active, dormant, and extinct volcanoes.
The Phlegraean Fields caused the largest volcanic eruptions in Europe and the Mediterranean region in the last 200,000 years. The last eruption of the Phlegraean Fields took place in 1538 with the Monte Nuovo eruption.
There are many signs that the Phlegraean Fields is a dormant volcano.
There are many fumaroles, especially in the Solfatara crater, which was believed in ancient Rome to be the home of Vulcan, the god of fire, from which the word for volcano comes from.
Bubbles of odorless CO2 gas called mofettas are released from Lake Avernus, which was believed in ancient Rome to be the entrance to the underworld controlled by Hades.
The area is known for the phenomenon called bradyseism, which is the gradual rise (positive bradyseism) or sinking (negative bradyseism) of the surface caused by the filling or emptying of the magma chamber. The surface has risen and sunk as much as 7 meters.
Movements in the magma chamber cause a lot of volcanic earthquakes, which are sometimes strong enough to be felt.
Account of the Rise of Monte Nuovo, in the Year 1538 [...] the earth opened near Tripergola with a terrible sound like thunder