Earthquake swarm prompts state of emergency for Campi Flegrei, Italy

A state of emergency was declared for the Campi Flegrei area in southern Italy on May 13, following an M4.4 earthquake and a series of related seismic events.

The decision was announced by Civil Protection Minister Nello Musumeci with the goal of expediting ongoing risk mitigation procedures in response to the area’s increased seismicity attributed to bradyseism.

“The persistence of the seismic swarm, which in two months has recorded three shocks clearly felt by the population, suggests the need to proceed with the declaration of a state of national emergency in the Campi Flegrei area,” Musumeci said.

The M4.4 earthquake occurred at 10:07 UTC (12:07 LT) near Pozzuoli, part of the Campi Flegrei caldera west of Naples. A subsequent M3.5 earthquake followed at 10:22 UTC.

The seismic events prompted evacuations of schools and public buildings, suspension of regional train services, and activation of emergency coordination centers.

According to the National Institute of Geophysics and Volcanology (INGV) Vesuvian Observatory, the seismic swarm began at 10:06 UTC on May 13 and consisted of 49 events with local magnitudes (Md) ranging from below 0.0 to a maximum of Md 4.4 ± 0.3. All earthquakes were located within the Campi Flegrei area.

The swarm ended during the morning hours of Wednesday, May 14.

The Campi Flegrei caldera is one of the most hazardous volcanic systems in Europe, located in a densely populated area that includes the city of Naples and the municipality of Pozzuoli.

The region is home to over 500 000 people living within the caldera’s immediate vicinity, making any volcanic or seismic unrest a major concern for civil protection authorities.

Seismic swarms in Campi Flegrei are linked to bradyseism, a phenomenon involving vertical ground displacement caused by underground magma or hydrothermal fluid movement. Recent scientific work suggests that managing groundwater extraction may reduce reservoir pressure and limit seismic activity.

Bradyseismic activity has been recurrent in this area for centuries, with notable episodes in the 1970s and 1980s resulting in significant ground uplift and the temporary evacuation of thousands.