Renewed Seismic Swarm hits Campi Flegrei – Epicenter close to critical Tangenziale Highway
Last night, the Campi Flegrei caldera was once again shaken by a seismic swarm. The strongest event reached a magnitude of 3.2, with the hypocenter located about 2,700 meters deep—beneath the hydrothermal system. Two additional quakes, measuring M2.2 and M2.0, occurred just before and after the main shock. All three epicenters were located northeast of Solfatara, near the Tangenziale highway that connects Pozzuoli to Naples.
This highway is the region’s main evacuation route in the event of a volcanic eruption. It passes through tunnels beneath the caldera’s volcanic hills. A stronger earthquake—above magnitude 5—could seriously damage this critical infrastructure, significantly complicating any last-minute evacuation. Therefore, expanding evacuation capacity via the sea appears increasingly necessary.
The M3.2 tremor was widely felt in Pozzuoli and nearby areas. Many residents reported it on social media. One user expressed concern about potential damage to the ruins of Pompeii, where a similar quake last month caused a wall to collapse.
The latest swarm began at 23:00 UTC and included around 30 individual tremors. Recent hopes that seismic activity might be declining—based on a few quieter days—now seem premature. Past patterns suggest that calmer phases often precede more intense swarms. As long as ground uplift continues, seismic stress will keep building. Even temporary slowdowns in uplift, as seen in past years, are no indication that the unrest is ending.