Earthquake in Naples: what are the Flegrei fields?

“At 01:25 Italian on 13 March 2025 a seismic event was located in the area of ​​the Flegrei fields of magnitude MD = 4.4 ± 0.3 and a seismic swarm has begun”. The National Institute of Geophysics and Volcanology tells him in a scientific way for those who warned the earthquake in Naples last night was afraid, strong as it hadn’t happened for years. The shock lasted about twenty seconds, was preceded by a strong roar and woke up the whole city. The epicenter was located 3 km deep: it is the strongest shock of intensity, together with that of May 20, 2024, of the last forty years. The next seismic swarm recorded a series of shocks of magnitude less than 2.

The prefect of Naples, Michele Di Bari, convened the rescue coordination center. The Civil Protection of Campania sent personal to Pozzuoli. The operational centers for the reception of those who cannot return to the house before the inspections were activated. Callinacci have fallen on the street and cars. In Pozzuoli the false ceiling of a Cada collapsed, a person was extracted alive by the rubble. Schools closed in Pozzuoli and in the neighborhoods of Bagnoli and Fuorigrotta: checks on the stability of the buildings must be made.

What are the Flegrei fields

The Flegrei camps are an active volcanic area located in Campania, in the Gulf of Pozzuoli. It touches the municipalities of Bacoli, Giugliano, Monte di Procida, Naples, Pozzuoli and Quarto. The name Campi Flegrei means ardent fields because this area is characterized by volcanic activities. It is not a volcano like Etna or Vesuvius, but a volcanic field, active for over 80 thousand years. There are numerous flues and thermal waters, known and exploited in antiquity.

They are several small volcanic centers that are found in a depressed area called Caldera and which would have been formed following large eruptions of the past: 40 thousand years ago theIgnimbrite Campana and 15 thousand years ago the Neapolitan yellow tuff. In this area the ground has collapsed due to these large eruptions. The first would have been the highest energy eruption that ever occurred in the Mediterranean, capable of influencing the climate probably on a planetary level.

In the Phlegraean camps there is the phenomenon of bradisism, that is, a slow deformation of the soil with lifting of the soil and sinking of the same. There is news of this phenomenon in this area from the 4th century AD. The Ingv explains that “in the periods 1970-72 and 1982-84 the Flegrea area was affected by bradisismic crisis In which the soil, in the town of Pozzuoli in particular, has undergone a maximum total lifting of about 3.5 m. The first crisis caused the forced abandonment of the dilapidated area of ​​Rione Terra; The second crisis in particular was characterized by intense seismicity with serious damage to the buildings. After the crises there was a period of general subsidiance, interrupted since 2005 by an inversion of the phenomenon that led to a constant lifting of the soil, at the moment still underway “.

About five hundred thousand people live in the Campi Flegrei area. Since 2012, the Grandi Rischi Commission has made the alarm level for Green Green to Yellow for the increase in SISMI and emissions and lifting of the soil. There are two emergency plans of the Civil Protection: in case of possible eruption, it provides for the movement within 72 hours of those who live in Pozzuoli, Bacoli and other neighboring municipalities, in addition to the western neighborhoods of Naples, for the seismic risk the red zone concerns the inhabited area of ​​the center of Pozzuoli and the neighboring areas.