Increase in both seismicity that of soil lifting at Campi Flegrei in the last week of monitoring (20-26 October 2025). The INGV Vesuvian Observatory reports in its latest bulletin 178 earthquakes (maximum magnitude 2.8), up compared to 135 the previous week, and a bradyseism speed that rises to a preliminary value of approximately 20 ± 5 mm/month (from 15 ± 3~mm/month previously). On October 25, two seismic swarms occurred in the Pozzuoli-Agnano Pisciarelli area with a maximum magnitude of 2.8. Geochemical parameters, such as the temperature in Pisciarelli (~ 94 °C), confirm the already known warming trend of the hydrothermal system. Despite the resumption of the phenomena, INGV does not detect elements that suggest significant developments in the short term.
Increasing seismic activity: 178 tremors and two swarms
From the 20 to 26 Octoberthe INGV has located at the Campi Flegrei 178 earthquakes with maximum magnitude of Mdmax=2.8. Of these shocks, 66 were recorded during two earthquake swarms both occurred on 25 October in the Pozzuoli-Agnano Pisciarelli area:
- The first swarm, which began at 02:37, consisted of 22 earthquakes with magnitudes between 0.0 and 1.5.
- The second, which started at 10.51pm, consisted of 44 earthquakes with Mdmax=2.8.
As usual, the tremors had a reduced depth, typical of bradyseismic seismicity.
From a geochemical point of view, however, the parameters confirm the already known long-term trends of heating of the hydrothermal system and increase in flows. In the last week, in particular, the temperature measured in a fumarole in the Pisciarelli area showed an average value of 94 °C, close to condensation of the fluid. Differently, in the area of the Solfatara crater, the temperature of the main fumarole (BG) confirms the increasing trend, with an average value of 166 °C.
Bradyseism and soil uplift: the data
From the point of view of bradyseism, the data of the last 15 days highlight a increased ground heaving. The average speed of ground rise has reached a preliminary average value of approximately 20 ± 5 mm/month.
INGV specifies that this value is to be considered provisionalawaiting further data. This figure marks an increase compared to the average value of approximately 15 ± 3 mm/month recorded from the beginning of April 2025. This speed however remains lower than the peak of 30 ± 5 mm/month recorded between mid-February and the end of March 2025.
From January 2025 the total lift recorded at the RITE GNSS station (Rione Terra) is approximately 17.5cm.
The latest bulletin on the Campi Flegrei in summary
In summary, the latest weekly bulletin on the monitoring of the Campi Flegrei:
- Seismicity: from 20 to 26 October were recorded 178 earthquakes of maximum magnitude 2.8. 66 of these occurred during two seismic swarms located in the Pozzuoli-Agnano Pisciarelli area.
- Soil lifting: show a increase with a preliminary value of 20 ± 5 mm/monthcompared to 15 ± 3 mm/month in the previous period.
- Geochemistry: stable parameters that confirm the already known trends of heating of the hydrothermal system and increase in gas flows emitted from the subsoil.
