Phlegraean Fields

The Phlegraean Fields (, ; ) 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.

 Volcanic eruptions 
 The strongest known eruption in the Phlegraean Fields occurred about 37,280 BC. This supermassive eruption emitted about 430 to 680 km³ of tephra and ignimbrite. The volume of this eruption was a magnitude of 7 on the Volcanic Explosivity Index (VEI). This was much more than the eruption of Tambora in 1815, which also had a magnitude of VEI 7. It was the largest volcanic eruption in Europe and the Mediterranean region in the last 200,000 years.

 A new study found evidence of a another supermassive eruption about 27,000 BC, the deposits of which were found in an area of about 150,000 km². It had a magnitude of VEI 7, but this was less larger than the eruption in 37,280 BC.

 In another major eruption in 13,000 BC, 40 km³ of material was emitted and 1000 km² of land was destroyed. It had a magnitude of VEI 6.

 The last volcanic eruption occurred in 1538, which was a small eruption. It was a lava eruption, which lasted for eight days, from September 29 to October 6. It destroyed the town of Tripergole and caused the deaths of 24 people. The town was never rebuilt.Il Villaggio di Tripergole - ArcheoFlegrei (in Italian) A new small volcanic mountain called Monte Nuovo (Italian for "New Mountain"), was formed from the lava and Lake Avernus (Lago d'Averno), a water-filled volcanic crater, which lies next to Monte Nuovo, was cut off from the sea.

 Volcanic activities 
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.

 Related pages 
 List of volcanos
 Dormant volcano

 References 

 Other websites 

Category:Calderas
Category:Volcanoes of Italy
Category:VEI-7 volcanoes
Category:Metropolitan City of Naples
Category:Campania