Campi Flegrei earthquake was felt in Naples.Italy's Campi Flegrei, a highly seismic zone near Naples, was shaken on Friday by a 4-magnitude earthquake, a few weeks after the area was hit by the strongest tremor in 40 years.The earthquake occurred at 09.14 at a depth of around 2.5 kilometres in the area between Pozzuoli and Bagnoli, Italy’s National Institute of Geophysics and Volcanology (INGV) said in a statement. The tremor sent panicked residents running into the streets, however there were no immediate reports of injuries. Firefighters said they were verifying structural damage to a building. Italy launches new earthquake early warning system for Rome-Naples trains In addition to the Campi Flegrei towns of Pozzuoli, Quarto and Bacoli, the earthquake was felt clearly in Naples. Earlier this year the Campi Flegrei area was hit by two strong earthquakes, including one of 4.4 magnitude in May and one of 3.9 magnitude in February. Campi Flegrei Declared a regional park 20 years ago, the Campi Flegrei area is a highly seismic zone of supervolcanic calderas, situated to the west of Naples and about 50 kilometres from Mount Vesuvius. The Campi Flegrei volcano last erupted in 1538 however earthquakes have been common in the area since 1950, with a surge of seismic unrest in the early 1980s. Experts believe the recent spike in seismic activity is linked to bradyseism, a phenomenon that involves the gradual uplift or descent of part of the earth's surface, caused by the filling or emptying of underground magma chambers or hydrothermal activity. There are 15 towns in the Campi Felgrei area with a combined population of more than half a million people living in the so-called 'red zone' most at risk. Last year the Italian government announced new measures in light of the increased seismic activity in the area, updating emergency plans for a possible mass evacuation.

Italy's Campi Flegrei, a highly seismic zone near , was shaken on Friday by a 4-magnitude earthquake, a few weeks after the area was hit by the . The earthquake occurred at 09.14 at a depth of around 2.5 kilometres in the area between Pozzuoli and Bagnoli, Italy’s National Institute of Geophysics and Volcanology (INGV) said . The tremor sent panicked residents running into the streets, however there were no immediate reports of injuries. Firefighters said they were verifying structural damage to a building.

• Italy launches new earthquake early warning system for Rome-Naples trains

In addition to the Campi Flegrei towns of Pozzuoli, Quarto and Bacoli, the earthquake was felt clearly in . Earlier this year the Campi Flegrei area was hit by two strong earthquakes, including one of  in May and one of  in February. Campi Flegrei Declared a regional park 20 years ago, the Campi Flegrei area is a highly seismic zone of supervolcanic calderas, situated to the west of Naples and about 50 kilometres from . The Campi Flegrei volcano last erupted in 1538 however earthquakes have been common in the area since 1950, with a surge of seismic unrest in the early 1980s. Experts believe the recent spike in seismic activity is linked to bradyseism, a phenomenon that involves the gradual uplift or descent of part of the earth's surface, caused by the filling or emptying of underground magma chambers or hydrothermal activity. There are 15 towns in the Campi Felgrei area with a combined population of more than half a million people living in the so-called 'red zone' most at risk. Last year the Italian government announced new measures in light of the increased seismic activity in the area, updating emergency plans for a possible .