Campi Flegrei, Doglioni: 'It's an active volcano, situation of attention, but no evidence of rising magma'

Since the beginning of the year in the Phlegraean Fields area, the Ingv (National Institute of Geophysics and Volcanology) operations room in Naples has detected almost 3,000 earthquakes, most of them of very low magnitude. Alarm among the population has risen due to the latest seismic swarm detected in the evening of 20 May. A seismic swarm in the Phlegraean Fields area which, up to 00:31 on 21 May 2024 local time, registered around 150 earthquakes. The magnitude 4.4 event was the most energetic of those recorded since the start of the current bradyseismic crisis that began in 2005. The Vesuvius Observatory, the Neapolitan branch of the Ingv, located the epicentre close to the Solfatara, in the municipality of Pozzuoli. We asked Professor Carlo Doglioni, president of Ingv, about the seismic situation in the Phlegrean area, where the population is on the alert. During the night 39 families were evacuated as a precautionary measure to allow checks on their homes, as announced by the prefect of Naples, Michele di Bari, during a press point at the Prefecture. The Pozzuoli women's prison was also evacuated.

First of all, Professor, what is the current situation and what have we learnt from the geological history of the Phlegraean Fields?

"The Campi Flegrei is a volcano, an active volcano. Bradyseism is one of the phenomena associated with this volcano and it is linked to the fact that there is a magma chamber at depth that releases gas seven to eight kilometres down, releases fluids, also releases magma that perhaps goes to reposition itself at a more superficial level and thus generate this thrust. A piston that generates a bell, which has its maximum uplift in the area of the so-called Rione Terra. This is an area that was already evacuated 40 years ago precisely because of the effects of bradyseism. Bradyseism, which then stopped and which also determined the end of seismicity. We have seismicity precisely because of the effect of this uplift, an uplift linked to the dynamism and vitality of the volcano'.

How do the latest seismic events fit in?

"They are related to the fact that this uplift has increased in speed. From one centimetre per month - for example last year we were half a centimetre per month - we have gone up to two to three centimetres per month. There have been times when the uplift has stopped. For example last autumn, around October-November, it was very slow. Then it picked up again with some speed. We reached peaks of up to four centimetres per month. Currently it has stabilised at around two centimetres. However, we must remember that when there was the bradyseismic crisis of 1983-84, there were periods when the ground was rising at up to nine centimetres a month. And when there was the last big eruption - which is a small volcano, Monte Nuovo inside the Campi Flegrei - the ground even rose by about 14 metres'.