Preprint Suggests Campi Flegrei Could Reach Critical Transition Around 2030–34, Authorities Caution

A newly posted arXiv preprint argues that unrest at Campi Flegrei, the large volcanic caldera west of Naples, is tracking toward a possible critical transition around 2030 to 2034. But the paper is not peer-reviewed, and the authors explicitly say “no evidence of imminent eruption is found.”

That distinction matters at a volcano already under close watch. Campi Flegrei sits in one of Europe’s most densely populated urban areas, with roughly 350,000 people living in the caldera proper and about 500,000 in Italy’s formal red zone for emergency planning. Italy’s civil protection alert for the area remains at yellow, and authorities have strengthened preparedness measures in late 2025 and early 2026 without declaring an eruption warning.

The preprint, posted April 28, is titled “Accelerating unrest at Campi Flegrei signals a critical transition within the next decade.” Its authors are Davide Zaccagnino, Didier Sornette, Antonio Giovanni Iaccarino and Matteo Picozzi. In the abstract, they say the volcano’s accelerating earthquake activity and ground deformation are “better described by a regularised finite-time singularity than by exponential growth.”

In plain terms, the authors argue that the recent unrest fits a time-to-failure style model better than a simple exponential trend. According to the paper, independent analyses converge on a critical time of about 2030 to 2034, with about 4 meters, or roughly 13 feet, of uplift by the early 2030s. That is the paper’s projection, not an observed outcome.

The same abstract says geochemical and statistical evidence points to deep magmatic volatile input — gases and fluids rising from depth — that is progressively pressurizing the crust. Campi Flegrei has been in its current unrest phase since about 2005, with renewed bradyseism, the slow rise and fall of the ground, accompanied by increasing seismicity.

The underlying acceleration, however, is not based only on this preprint. A peer-reviewed 2024 study in Communications Earth & Environment found that Campi Flegrei’s uplift showed a decadal accelerating trend and that seismicity increased supra-exponentially through 2023. It also found that the correlation between uplift rate and earthquake count strengthened from about 2020 onward.

That earlier work helps separate what is well established from what is newly proposed. The acceleration in uplift and earthquakes has already been documented in the scientific literature. What is new in the preprint is the interpretation that those data are approaching a finite-time critical transition in the early 2030s.

Italian monitoring authorities have been careful to draw a line between scientific analysis and operational warning. In a press release summarizing the related 2024 research, Italy’s National Institute of Geophysics and Volcanology, or INGV, said: “The published research has an essentially scientific value, without immediate implications regarding the aspects of civil protection at the moment.” That official stance remains important here: the alert level is still yellow, not red, and monitoring and civil-protection decisions are not driven by a preprint alone.

The stakes are nevertheless high. Campi Flegrei is one of the world’s most hazardous volcanic systems because of the number of people living nearby and the complexity of evacuating the Naples-area communities covered by Italy’s emergency plan, which includes designated red and yellow zones.

The caldera last erupted in 1538, when Monte Nuovo formed. It has also gone through major bradyseismic crises in 1950-52, 1969-72 and 1982-84. The 1982-84 episode produced about 1.8 meters of uplift, strong seismicity and partial evacuations, but no eruption.

That history is a reminder that unrest at Campi Flegrei does not automatically mean an eruption is imminent. The new preprint adds a sharper forecast to an already documented pattern of accelerating unrest, but for residents and policymakers, the key signals remain the ones coming from continuous monitoring and Italy’s existing emergency framework.