A 4.4 magnitude earthquake struck Italy’s Campi Flegrei super volcano Monday evening, causing mild damage in the town of Pozzuoli, the epicenter, and as far away as the city of Naples, some 20 kilometers (12 miles) away, according to Italy’s National Institute of Geophysics and Volcanology (INGV).
Cracks in walls and falling cornices were reported, Italy’s Fire Brigade spokesman confirmed to CNN.
The 4.4 earthquake at a depth of 3 kilometers is the strongest earthquake to hit the highly seismic area in the past 40 years, according to INGV data. The quake is part of an ongoing “seismic storm” that has seen more than a dozen events over 2.0 magnitude in the past 48 hours.
The 4.4 tremblor at 8:10 p.m. local time was preceded by a 3.5 earthquake an hour earlier.
The INGV recorded 1,252 earthquakes in the Campi Flegrei area in the month of April 2024, most with a magnitude less than 1.0.
The last major eruption of the supervolcano was in 1538, which resulted in the creation of a new bay on the southern Italian coast. The INGV has noted an increase of seismic activity since 2022, which could be due either to the building up of magma under the surface or the building up of gases, according to several volcanologists.
The volcano is about 50 kilometers (31 miles) from Mt. Vesuvius, and prone to a phenomenon known as bradyseism, during which the ground raises and falls due to pressure under the surface. The last major cycle was in 1984, but several volcanologists told CNN that the area is experiencing a new cycle of the phenomenon.
More than 500,000 people live in the red zone directly adjacent to the Campi Flegrei, according to the Italian Civil Protection agency, which has been working this year to update evacuation plans in the event of a major disaster.