The volcanic zone of Campi Flegrei, on the outskirts of Naples, is once again in the spotlight due to a series of low magnitude earthquakes and a continuous uplift of the ground. Although the earthquakes are moderate, the sequence is persistent enough to worry the local population and spark interest throughout Europe, including in countries such as Spainwhere it is closely monitored the evolution of this volcanic complex.
The most recent data from the National Institute of Geophysics and Volcanology (INGV) and the Vesuvius Observatory paint a picture of sustained activity But there are no signs, for now, of any imminent abrupt changes. The so-called bradyseismThis slow, up-and-down movement of the caldera's terrain continues at a rapid pace, while seismic swarms and isolated tremors are recorded, sometimes accompanied by rumors or underground noises perceived by the neighbors.
A new earthquake wakes the population in the middle of the night
Among the recent episodes that have attracted the most attention is one scossa of magnitude 3,2The earthquake, recorded around 5:00 AM in the Campi Flegrei area of ​​Naples province, had a magnitude of 10. very superficial hypocenter, at a depth of just 3 kilometers, and a epicenter located between Pozzuoli and Quarto, two densely populated municipalities in the Naples metropolitan area.
The magnitude 3,2 tremor was preceded and followed by several weaker tremors During the same night, between 1:00 and 6:00 a.m., at least a dozen small tremors were recorded, forming a sequence that, although it caused no damage, did generate some concern. concern among residents and numerous calls to emergency services.
On another day, the Vesuvius Observatory reported two almost simultaneous seismic events, both felt in the area of Via Antiniana and Via GerolominiThe first one reached an estimated magnitude of 2,0 (with an uncertainty of ±0,3) and originated at a depth of about 2 kilometers; the second, of approximate magnitude 1,6It was located at a depth of only 600 meters.
These tremors, which occurred around 00:42 (local time)They were able to be accompanied by a dull or explosive noise —the typical pomp—, perceived by those living near the epicenter. Although the magnitude values ​​are low, the combination of shaking and underground noise usually increases the sense of alarm among the population.
Local authorities and the Italian Civil Protection have reiterated that, despite the concern, No personal or material damage has been reported linked to these events. The main recommendation is to stay informed through the official channels and avoid being swayed by rumors or unverified information circulating on social media.
Weekly spike in earthquakes and emergence of seismic swarms
Beyond isolated incidents, scientists observe the global evolution of seismicity in the caldera. During the week of December 15-21, 2025, the Vesuvius Observatory detected a total of 76 earthquakes located in the Campi Flegrei area. This figure is more than double the 34 events recorded in the previous week, which had marked the monthly low.
The maximum magnitude of this weekly series remained around 2,0That's why we talk about earthquakes light, but numerousA large part of these tremors were concentrated in seismic swarms, sequences of small earthquakes that occur in a short interval of time and in a very specific area of ​​the subsoil.
During that period, the following were identified: two distinct swarms:
- El sciame of December 15 It began at 07:47 and consisted of five earthquakes in the Pozzuoli area, with a maximum magnitude of 1,9.
- El sciame of December 19 It started at 04:42 and also registered five events, in this case with one maximum magnitude of 2,0.
These episodes are in addition to other moderate earthquakes, such as one of magnitude 1,6 detected at 03:50 on December 19th and another from 1,5 at 17:16 PM on December 18. Taken together, they describe a pattern of persistent seismic activity, consistent with the current phase of agitation of the volcanic system, but without exceeding the levels of energy released observed in previous months.
According to the INGV, this type of dynamic is compatible with the bradysism process Ongoing: minor crustal readjustments caused by the upwelling of fluids (gases, steam, and hot water) and the pressure accumulating beneath the caldera. For now, the earthquakes remain mostly of low magnitude and at shallow depths, a trend that experts are continuously monitoring.
Bradysm: the ground continues to rise at high speed
The other main protagonist in Campi Flegrei is the bradyseism, that phenomenon of slow deformation of the ground which, in this case, manifests primarily as ground uplift. Since October 10, 2025, the average uplift rate in the area of ​​maximum deformation has remained stable at around 25 ± 3 millimeters per month, a high figure for this type of process.
The measurements obtained at the GNSS station of Rione Terra (RITE)In Pozzuoli, they indicate that the cumulative lift Since January 2025 it has been around 21,5 centimetersThis data is especially relevant for local and regional authorities, as it serves as a reference for assessing potential impacts on infrastructure, marinas, service networks and old buildings.
In simple terms, the ground under part of the urban area of ​​Pozzuoli has risen to the equivalent of the height of a standard brick throughout the year, something that may seem small at first glance but, from a geological and urban planning point of view, is a remarkable change.
This deformation process is not new in Campi Flegrei: bradysm is part of the geological and social history of the area, with documented episodes dating back to antiquity. What worries experts is not so much that the phenomenon exists, but its rhythm and persistenceas well as the need to adapt the territory from an urban planning perspective to this changing reality.
According to the latest bulletins, the current trend of bradysism Its speed remains stable, with no clear signs of sudden acceleration. However, the INGV insists that monitoring must be constant, as changes in ground deformation can anticipate modifications in the internal dynamics of the volcanic system.
Temperatures and gases: the hydrothermal system remains very active
In addition to seismicity and deformation, scientists closely monitor the geochemical parameterswhich provide key information about the state of the hydrothermal system located beneath the caldera. In this area, recent data confirm a long-term heating process, without any sudden changes in recent weeks.
In the crater of the Solfatara, one of the most emblematic points of Campi Flegrei, the temperature of the main fumarole (known as BG) remains high, around 173 ° C on average. These values ​​confirm that the system remains thermally very active, with a constant supply of hot gases from the subsoil.
In the nearby area of PisciarelliIn another closely monitored area of ​​gas and fluid emissions, the average temperature is around 94 ° CThis is a slight decrease compared to previous stages, but still within a typical range. vigorous hydrothermal system, with abundant fluid circulation and continuous steam release.
Combining high temperatures, gas emissions and ground deformation This is characteristic of volcanic calderas in a phase of unrest. It does not necessarily imply an imminent eruption, but it does require maintaining a dense network of instruments and periodically updating civil protection plans.
These parameters are also of great interest to other European countries, including Spainwhere there are active volcanic zones such as the Canary Islands. The behavior of Campi Flegrei is often analyzed in international scientific forums for improve surveillance models and risk management in populated volcanic environments.
What the experts say and how the risk is managed
With this scenario of frequent seismic activityWith sustained bradysma and a hot hydrothermal system, the question many are asking, including those outside Italy, is to what extent the situation is worrying. Bulletins from the INGV and the Vesuvius Observatory emphasize that, based on current data, no elements are observed that suggest significant changes in the very short term.
This does not mean that the risk is nonexistent, but rather that the evolution of the system is considered gradual and within the scenarios considered by specialists. In an environment as complex as Campi Flegrei, scientists avoid making definitive predictions and prefer to talk about probabilistic scenarios, updated as new seismological, geodetic and geochemical data are incorporated.
The Italian authorities, for their part, maintain a permanent surveillance devicewith seismographic stations, GPS, thermal sensors, and periodic gas analyses. In addition, information campaigns are being developed to raise awareness among the local population about the action protocols in case of emergency and know how to behave in the event of tremors, underground noises or anomalous emissions.
Official statements emphasize that, should citizens have any doubts, they should consult the information available in the websites of the Vesuvius Observatory and the INGVas well as following the instructions of Civil Protection. The aim is to reduce the circulation of hoaxes and alarmist messages, while promoting a culture of prevention that could make a difference if the situation were to worsen.
This approach is especially relevant for other European territories with volcanic risk, who view the Campi Flegrei case as an example of how to combine science, urban planning and public communication in a context of geological uncertainty.
The current situation in Campi Flegrei is characterized by a combination of small earthquakes, continuous ground uplift and high hydrothermal activity While not constituting an imminent emergency, it necessitates continued vigilance. Close scientific monitoring, regular bulletins, and coordination with Civil Protection are, for now, the main tools for living with a complex volcano in one of the most densely populated areas of southern Europe, as citizens, authorities, and experts come to terms with the fact that absolute calm is not part of the typical landscape of this caldera.