The Phlegraean Fields are strangely quiet

For over a year, the super volcano has kept many people on tenterhooks with earthquakes and enormous ground uplift. But now it seems to be on holiday.

Pozzuoli – It is a monstrous specter that keeps more than three and a half million people in the greater Naples area on tenterhooks. Half a million of them live in its red zone alone: ​​the super volcano of the Phlegraean Fields in southern Italy. It is considered potentially the most dangerous volcano on earth, as more people live on it than anywhere else on such a lava field. In the past it has brought death and destruction to the region within a radius of up to 80 kilometers at least twice. It is even said to be partly responsible for the extinction of the Neanderthals.

A characteristic of the huge caldera with a diameter of 16 kilometers is that it seems to breathe. It rises and falls. Since the height of the Roman Empire, the water has fallen dramatically, which is why the ruins of the ancient port city of Baiae sank and are still underwater. Up until the High Middle Ages, the water level fell by around 20 meters from the birth of Christ. This was followed by a rise of around 15 meters, which ended with the eruption of Monte Nuovo near the port city of Pozzuoli in 1538, which was small compared to the Ice Age eruptions. After that, it fell again by a good five meters until April 1950. Since then, the water level has risen again – by more than six meters.

The super volcano in Italy seems to breathe – the ground rises and falls, sometimes it erupts

In the 1970s and 1980s, two uplift phases accompanied by earthquakes led to evacuation measures. Since the middle of last year, a new uplift phase, accompanied by some relatively violent earthquakes, has caused fear and terror – the fear of a new eruption grew ever greater. Up to 1,430 earthquakes per month were recorded, especially in June and July. Even a section of cliffs collapsed into the sea. The most violent tremors had magnitudes of 4.4, there was damage to buildings, hundreds of houses were evacuated and need to be renovated.

But since mid-August, the super volcano seems to be on holiday. Shortly before Ferragosto, the Assumption of Mary (15 August) and the day when all of Italy goes to the beach, the Phlegraean Fields once again let loose with 142 quakes in one day, but since then it has been relatively quiet. There are now only a maximum of 20 tremors a day, and at times the app that reports the tremors to the locals for 24 hours no longer showed any tremors at all. The last weekly balance: Between August 26 and September 1, 2024, 28 earthquake registered, the week before there were 34. Although there was also a smaller swarm earthquake with the largest shock of magnitude 3.7, the trend is still clearly downward.

Supervolcano suddenly quiet: Just in time for Ferragosto, the Phlegraean Fields seem to be on holiday

The figures reported by the altimeters around the port city of Pozzuoli, which lies at the centre of the supervolcano, are even clearer: On Tuesday, the second encouraging weekly report was released by the Vesuvius Observatory for the Phlegraean Fields, which is managed by the National
Institute of Geophysics and Volcanology (INGV): The most important message: the rate of uplift of the supervolcano has slowed down. “In the last 20 days, the speed of ground uplift has decreased,” says the latest report from the Vesuvius Observatory. The curve has become flatter on the INGV side.

But the researchers are still cautious about giving the all-clear: “Real progress can only be determined with the data from the next few weeks,” the website says. After all, the uplift rate is said to have reduced from two centimeters per month to one and a half centimeters.

Is the lull at the supervolcano in Italy a good or a bad omen?

Hope is growing among the region’s residents: “We hope that the increase will go to zero and then it will go down again,” writes one user in the Facebook group of residents in the red zone of the super volcano. Another is not quite so optimistic: “I think the positive thing is that the number of earthquakes has decreased, but the speed of the ground heaving remains. Others see the current silence as a bad omen: “Slowing down does not mean that it is over or worse, it could be an indication of an eruption. Perhaps we are facing a mega-crash.”

Recently, other Italian volcanoes have caused a sensation: Europe’s largest volcano, Mount Etna, provided impressive images with spectacular eruptionsThe small Stromboli on the small island of the same name seemed to want to engage in a duel with its big brother and also erupted violently.