Earthquake: Ground acceleration at Solfatara reached 0,9g, one of the highest values ​​ever recorded.

Preliminary data released by the INGV confirm that the magnitude 4.7 earthquake that struck the Campi Flegrei area yesterday caused particularly intense ground shaking in the eastern Solfatara area, where one of the highest ground acceleration values ​​of the entire bradyseismic crisis was recorded.

The peak recorded at Solfatara

The seismic station at the Tennis Hotel Solfatara, managed by the Vesuvius Observatory, detected a peak ground acceleration (PGA) of 0,9 g, an extremely high value that indicates that the ground was subjected to a thrust equal to almost 90% of the Earth's gravitational force.

This is the second highest value recorded in Campi Flegrei since the beginning of the current phase of bradyseism, lower only than the 1,1 g measured during the magnitude 4.6 earthquake of March 13, 2025.

A very localized shaking

Experts emphasize, however, that the value of 0,9 g concerns an extremely limited area, between Solfatara and Pisciarelli, and does not represent the entire Phlegraean Fields.

The distribution of ground shaking, in fact, can change significantly even at a distance of just a few dozen meters. This is demonstrated by the station on Via San Gennaro, located a little further south, which recorded a significantly lower acceleration, in the order of 0,1 g.

Intermediate values ​​were detected at the stations of the Port of Pozzuoli, Arco Felice and Via Campana, where the peaks reached approximately 0,3 g, levels nevertheless considered significant by specialists.

Why ground acceleration is a crucial factor

For scientists, ground acceleration is even more indicative than magnitude alone in assessing the effects of an earthquake. This data allows for near-real-time knowledge of the actual intensity of the shaking, identifying the areas that have experienced the greatest stress and where damage to buildings and infrastructure is most likely to occur.

Analyzing the recordings from various seismic stations therefore allows us to more precisely reconstruct the distribution of the energy released by the earthquake and to direct technical checks in the most exposed areas.