The current crisis
A new uplift phase of the Phlegraean Fields caldera began in 2005 and is still ongoing. As of the end of September 2024, the maximum uplift value reached in Rione Terra in Pozzuoli (point of maximum caldera deformation) is about 133.5 cm, including about 15.5 cm since January 2024.
Seismicity. Since 2018, this phenomenon has been followed by a gradual increase in seismic activity, including the number of earthquakes and their magnitude. In 2023, while most events had low magnitudes (about 90% had magnitudes below 1.0), there was a new increase in the frequency of earthquakes. Most of the events occurred between Astroni, Solfatara-Pisciarelli-Agnano, Pozzuoli, and Gulf of Pozzuoli, with maximum depths of about 4 km, primarily concentrated in the first 2 km. In the same year, the strongest events occurred on September 27 and October 2, with magnitudes of 4.2 and 4.0, respectively. In 2024, the strongest event occurred on May 20 with a magnitude of 4.4 in the Solfatara of Pozzuoli area.
Comparison with the bradyseismic crisis of the 80's. The current situation is marked by ground uplifts and earthquakes of a magnitude comparable to those experienced in the bradyseismic crisis of 1982-84, while in terms of impact on buildings and infrastructure, the picture is very different. The 1980s crisis caused extensive damage to buildings, particularly in the municipality of Pozzuoli, leading to the evacuation of the population from their homes in the historic center. This was similar to what happened during the bradyseismic crisis of the 1970s when the inhabitants of the Rione Terra had to be evacuated.
The current bradyseismic crisis has not caused significant damage so far. The reasons are to be found in the different vulnerabilities of the buildings and the different evolution of the phenomenon in the frequency of quakes and the rate of uplift. Most of the structures in the area today consist of buildings not exceeding three stories, mostly made of reinforced concrete or masonry, which have undergone seismic retrofitting interventions since the 80's. To this end, with the Ministerial Decree issued by the Ministry of Public Works on March 7, 1981, the municipalities in the Phlegraean area were classified as seismic with strict adherence to construction regulations.
Initial response to the crisis. The recent escalation of the bradyseismic crisis, culminating in September and October 2023 events, required the strengthening of volcano monitoring activities by Ingv and other Centers of Compentence and, more generally, a tightening of preventive measures by the Civil Protection System.
The opinion of the National Major Risks Commission. In the last months of 2023, the Department has called the National Major Risks Commission - Volcanic and Seismic Risk Sector several times to know its opinion on the current situation and to perform further analysis and investigations, given the complex nature of the issue and the potential evolution of the volcano's dynamics. Several national and international experts were also involved to have further assessment elements.
As a result of these meetings, the Commission found that the scientific findings reinforce the evidence for the presence of deep-seated magma as the root cause of the current bradyseismic crisis. However, without evidence of rising magma, it was concluded to confirm "the yellow alert level for volcanic risk." Therefore, the Commission believes that monitoring activities by the Centers of Competence and prevention activities by the various components of the National Service should be further strengthened and prepared for the potential need to increase the alert level.