A magnitude 4.6 earthquake struck the Campi Flegrei area in southern Italy—marking the strongest quake in the region in 40 years. The tremor, which occurred at 12:47 p.m. local time (10:47 UTC), had its epicenter offshore between Pozzuoli and Bacoli at a shallow depth of 4–5 kilometers (2.5–3.1 miles). It was part of a seismic swarm that included seven events, according to Italy’s National Institute of Geophysics and Volcanology (INGV).
The earthquake was strongly felt throughout the western parts of Naples, prompting the evacuation of buildings and schools, including the Righi Institute in the Fuorigrotta district. No injuries were reported, but the tremor caused localized damage and widespread panic. The Italian Civil Protection Agency confirmed transport disruptions, including train delays of up to 120 minutes across high-speed, intercity, and regional services.
The ridge of Pennata islet collapsed during today’s M4.6 earthquake at Campi Flegrei.
— Volcaholic 🌋 (@volcaholic1) June 30, 2025
📹 Gregorio Rucco/fb pic.twitter.com/HtSPnn5cK6
One of the most visible consequences was the collapse of a rocky ridge on Punta Pennata islet in Bacoli, shortly after the main shock. The area, already subject to access restrictions due to erosion risk, is now under renewed scrutiny. Authorities reiterated the need for structural interventions to secure the coastal cliffs, which are composed of vulnerable tuff rock and show signs of progressive instability.
Bacoli’s mayor voiced concern that planned safety works along the shoreline have not yet begun, despite long-standing known risks. Local officials have called for immediate government support to stabilize the cliffs and protect both residents and tourists.
This latest quake follows two magnitude 4.4 events earlier this year, in March and May, and is part of an ongoing pattern of seismic unrest linked to bradyseism—a phenomenon involving vertical ground movement caused by underground magma or hydrothermal activity. Campi Flegrei is one of Europe’s most hazardous volcanic systems, with over 500,000 people living within the caldera’s immediate vicinity.
In the wake of the quake, authorities activated emergency protocols. Structural inspections and technical surveys are underway across the region, particularly in coastal areas with known erosion issues. Residents have been advised to avoid high-risk zones and comply with all local safety ordinances while monitoring of the seismic swarm continues.
