A dormant volcano just outside Rome could be slowly reawakening, scientists have said, raising fears of a Pompeii-style ash-and-rock cloud sweeping across the Italian capital.

An eruption in the Colli Albani Volcanic District (CAVD), which is around 10km from Rome, would have a devastating impact on much of the city.

In a study published in the journal Geophysical Research Letters, an international team of researchers reported that the ground in the region is rising by 2-3mm per year and underground chambers located several kilometres below the towns of Ariccia, Castel Gandolfo and Albano are filling up with magma – signs that the previously dormant volcano is rumbling back to life.

Satellite imagery and seismographic charts also record the volcano’s slow awakening.

However, while the volcano’s increased activity is a cause for concern, experts believe a possible eruption could still be 1,000 years away.

Previous studies have suggested the volcano tends to erupt around every 40,000 years.

But now scientists believe that could be narrowed to 30,000 years – bringing the prospect of an eruption much closer.

If the volcano did erupt, it would produce a huge cloud raining down ash and lava on parts of Rome. The cloud would obscure the sun in countries as far away as Latin America, scientists believe.

Experts say the long gaps between eruptions are a cause for concern because they allow time for large quantities of magma to build up and pressure to mount below the earth’s surface. This means the eventual eruption is likely to be bigger and more powerful.

“When the eruption happens, it has an explosive effect, like opening a champagne bottle after shaking it,” Fabrizio Marra, who led the study, told La Repubblica.

“This sort of process has, for example, caused the string of earthquakes that hit this area at the beginning of the 1990s, with minor quakes and a few cases of magnitude four quakes.”

Mr Marra said people living near the volcano should not fear an eruption – at least not yet.

In pictures: Most powerful earthquake for three years hits Italy Show all 13 1 /13 In pictures: Most powerful earthquake for three years hits Italy In pictures: Most powerful earthquake for three years hits Italy Fractures on a road in Norcia after the strong earthquake in central Italy EPA/Matteo Crocchioni In pictures: Most powerful earthquake for three years hits Italy The bell tower of St. Augustine's church destroyed after the strong earthquake in central Italy, Amatrice EPA/Massimo Percossi In pictures: Most powerful earthquake for three years hits Italy Nuns rest on a bench after been evacuated from their monastery following an earthquake in Norcia, Italy REUTERS/Remo Casilli In pictures: Most powerful earthquake for three years hits Italy The church of the Madonna of the Angels is seen partially collapsed following an earthquake along the road to Norcia, Italy Reuters In pictures: Most powerful earthquake for three years hits Italy A powerful earthquake rocked the same area of central and southern Italy in August and a pair of aftershocks last week, sending already quake-damaged buildings crumbling after a week of tremors that have left thousands homeless Vigili Del Fuoco/Italian Firefighters via AP In pictures: Most powerful earthquake for three years hits Italy A 6.6 magnitude earthquake struck 6km north of Norcia, Italy, EPA In pictures: Most powerful earthquake for three years hits Italy A 6.6 magnitude earthquake struck 6km north of Norcia, Italy EPA/Alberto Orsini In pictures: Most powerful earthquake for three years hits Italy People are evacuated from an hospital following an earthquake in Rieti, Italy REUTERS/Emiliano Grillotti In pictures: Most powerful earthquake for three years hits Italy L'Aquila Mayor Massimo Cialente speaks on his mobile telephone as he checks the damage after the strong earthquake in L'Aquila, central Italy EPA/Alberto Orsini In pictures: Most powerful earthquake for three years hits Italy Italian firefighters escort a frightened woman out of a building just as an aftershock rattled Norcia, central Italy AP Photo/Gregorio Borgia In pictures: Most powerful earthquake for three years hits Italy A view of Amatrice village completely destroyed after the strong earthquake in central Italy EPA/Massimo Percossi In pictures: Most powerful earthquake for three years hits Italy A firefighter and an alpine soldier look at rubble in the hilltop town of Amatrice as an earthquake with a preliminary magnitude of 6.6 struck central Italy Massimo Percossi/ANSA via AP In pictures: Most powerful earthquake for three years hits Italy A handout map released by the US Geological Survey (USGS) shows the location of the earthquake striking around 68km east-southeast of Perugia, Italy EPA

The more imminent threat is from earthquakes triggered by the increased activity under the earth’s crust.

Earthquakes can, in certain circumstances, trigger volcanic eruptions but this is not currently a risk in Rome because the volcano is still too far away from its next eruption.

Mr Marra said: “It has been ascertained that a seismic event could trigger a volcanic eruption, as happened in the US with Mount St Helens. But it can only happen with a volcano on the verge of erupting, at these levels there is no possible disturbance that could reach the magma chambers.”

The team, from the National Institute of Geophysics and Volcanology in Rome, mapped 600,000 years of the region’s history and assessed the habits of the volcano.

They concluded that the cycle of past eruptions suggest another is due within the next 1,000 years – a finding in line with the increased volcanic activity in the region.

The warning comes as Italy’s biggest earthquake in 36 years left more than 15,000 people homeless in and around the town of Norcia in central Italy.