A 4.0-magnitude earthquake has rocked Italy’s volcanic Campi Flegrei region near Naples, just days after a leading volcanologist warned of the need for evacuation plans in the area.
The quake, which occurred shortly after 10pm on Monday night, did not cause any damage or injuries, officials said, although it did cause panic among residents.
The epicentre was located at a depth of nearly two miles between Naples and Pozzuoli, according to Italy’s National Institute of Geophysics and Volcanology.
The constellation of ancient volcanic craters sits across the bay of Naples from Pompeii, where thousands were incinerated by Mount Vesuvius in 79 AD.
However, it is a much bigger volcano than Vesuvius and if it ever exploded at full force could kill hundreds of thousands. Some half a million people live in the immediate region around Campi Flegrei.
On Wednesday, a 4.2-magnitude quake was recorded, the strongest in the area for 40 years.
Although experts say there is no risk of an imminent eruption, a leading volcanologist last week warned that preparations for a mass evacuation could be needed.
Giuseppe De Natale, the former head of the Vesuvius observatory at the National Institute for Geophysics and Volcanology (INGV), said the last time Campi Flegrei suffered a similar burst of earthquakes in the 1980s, some 40,000 people were temporarily evacuated from nearby Pozzuoli.
The town now has a population of more than 80,000.
“Currently, I believe the more immediate risk is seismic. But it is clear that one must also consider the possibility of an eruption," he told Reuters.
He said if there was an eruption, it would be a steam-blast eruption, which are generally relatively weak and devoid of new magma, at least initially.
Mr De Natale said he had written to the government suggesting possible evacuations, with officials saying it was under review.
A local official said his recommendation was being reviewed.
The Campi Flegrei caldera has a diameter of about 12-15 km (7.5-9.3 miles) and last erupted in 1538.
One of its biggest eruptions took place some 39,000 years ago and might have led to the extinction of Neanderthal man, researchers believe.
Magma from that blast has been found in Greenland, some 4,500 km away.
Volcanologists say thousands of small tremors in the area since 2019, which have grown in intensity this year, might be being triggered by tongues of magma pushing up into the subsurface of the volcano at a depth of about five to six kilometres.
