Supervolcano near Naples is about to erupt, but no one knows when

The ground under Pozzuoli, a town west of Naples, is rising at about 15 millimeters per month. This deformation of the earth is accompanied by earthquakes, dozens a day. Most have a force of about 2 on the Richter scale, but sometimes it goes even faster.

“I felt one a few weeks ago, it was 3.5 on the Richter scale.” Peppe Renzuto lives with his Dutch wife Iris de Brouwer just outside Pozzuoli. He was born and raised in the area. Peppe and Iris’ house is still just in the red zone, which means that they are basically in great danger. “If there is an alarm, we have to leave our house immediately and go to the assembly point a few 100 meters from our house. And that can be during an eruption, which, like earthquakes, is difficult to predict.”

All municipalities in the area have an evacuation plan in case things go wrong: the area must be cleared within 72 hours. Including the city of Naples, this is about three million people. In the first twelve hours of the alarm, people are still allowed to leave with their own transport, after which the residents are obliged to evacuate with buses. Those who have no alternative are taken care of in other parts of Italy.

Giuseppe Mastrolorenzo looks from the roof terrace of his summer house on the bay of Pozzuoli, the epicenter of the volcanic activity. “In principle, the volcano can erupt at any time.” Mastrolorenzo is a volcanologist at the Italian Institute of Geology and Volcanology, the INGV. “We constantly monitor the Campi Flegrei and know exactly what happened down to the millisecond, but we cannot predict what will happen in a millisecond, the system is too complex for that.”

The Campi Flegrei, literally ‘the burning fields’, is a so-called super volcano. A volcano with a diameter of between 15 and 18 kilometers and about forty larger and smaller craters. The Campi Flegrei lie largely below the city of Naples and the Bay of Pozzuoli to the west of the city. “An eruption creates new craters every time, so craters could just form in the city of Naples itself.”

The last really big eruption of the Campi Flegrei was thirty thousand years ago, when the area was flooded by lava and the peninsula was formed on which the town of Pozzuoli is now located. The last eruption dates from 1538, when a new mountain was formed in a few days in a relatively small eruption, Monte Nuovo. That eruption was preceded by the same deformation of the Earth as it is now.

“Peppe is pretty sober about it, isn’t he,” says Iris de Brouwer via a video call from the Netherlands, where she is now on vacation. “I am much more concerned with the idea of ​​living on a volcano than he is.” Peppe laughs, he’s used to it. “When our eldest son went to the lyceum, I thought, should I send him to the school at the foot of the crater or do we send him to school in Naples, not all the way on top of the volcano? Anyway, the school where he is now is close to another crater. You can’t do much about it and you don’t move that quickly either.”

In Rione Terra, the ancient Greco-Roman district of Pozzuoli, you can clearly see what the volcano is doing. The inner harbor for the district is largely dry, the ground has risen so far that the sea water level has dropped dramatically. The boats that are still there are stuck in the mud.

In 1972 this district was hurriedly evacuated, five thousand families had to leave their homes, because the earth was already rising and people feared an eruption. Ten years later, forty thousand inhabitants of the city had to leave their homes. The question is whether that is also the case now. “We don’t know,” says volcanologist Mastrolorenzo, looking out over the dry harbor.

“There are currently two different theories. One says that the uplift of the soil is caused by a filling magma chamber, another theory says that the porous soil fills up with gases and liquids and that the soil absorbs it like a sponge.” According to Mastrolorenzo, you cannot base an evacuation plan on conflicting models. “That is a political decision. The volcano does not listen to that.”

“Pozzuoli is like bread dough,” says Gennaro, an elderly man eating an ice cream at the harbor. ,,In the evening you make the dough, then you cover it with a cloth and then it will rise, that’s Pozzuoli. It may continue to grow, it may collapse or even explode. We do not know.”