While the Campi Flegrei volcano hasn't erupted since 1538, experts have warned that it could be building up to another devastating eruption.
By studying patterns of unrest over the last 500 years, the researchers have predicted that it is reaching a 'critical stage' where further unrest will lead to an eruption.
They hope their findings will urge local authorities to prepare for an eruption, which they say would affect the 360,000 people living across the caldera and Naples' population of nearly one million.
If the volcano was to erupt, it could cause havoc for those trying to fly in the area.
Dr Christopher Kilburn, who led the study, told MailOnline: 'An eruption might disrupt air traffic, if only for precautionary measures and the immediate effect would be in Campi Flegrei and Naples.'
Experts from UCL and the Vesuvius Observatory in Naples have been studying the patterns of unrest since Campi Flegrei's last eruption 500 years ago.
The volcano has been restless for 67 years, with two-year periods of unrest in the 1950s, 1970s and 1980s causing small, local earthquakes and ground uplift.
Similar unrest occurred over 500 years ago, when it took a century to build up to an eruption in 1538.
Using a new model, the researchers investigated whether Campi Flegrei may again be preparing to erupt.
They found that the unrest since the 1950s has been causing a build-up of energy in the crust and making the volcano more vulnerable to eruption.
Until now, scientists had thought that the energy needed to stretch the crust was lost after each period of unrest.
Dr Kilburn said: 'By studying how the ground is cracking and moving at Campi Flegrei, we think it may be approaching a critical stage where further unrest will increase the possibility of an eruption, and it's imperative that the authorities are prepared for this.
'We don't know when or if this long-term unrest will lead to an eruption, but Campi Flegrei is following a trend we've seen when testing our model on other volcanoes, including Rabaul in Papua New Guinea, El Hierro in the Canary Islands, and Soufriere Hills on Montserrat in the Caribbean.
'We are getting closer to forecasting eruptions at volcanoes that have been quiet for generations by using detailed physical models to understand how the preceding unrest develops.'
The episodes of unrest are caused by the movement of magma around three kilometres below the volcano.
An eruption becomes more likely when the ground has been stretched to its breaking point.
This is because the molten rock can escape to the surface when the ground splits apart.
But it is difficult to pinpoint when an eruption will occur, because even if the ground breaks, it is possible for the magma to stall before reaching the surface.
Although it hasn't erupted, unrest at the volcano has alredy caused severe social disturbanced in Campi Flegrei.
Together, the three episodes of uplift have pushed the port of Pozzuoli more than three metres out of the sea.
Dr Stefano Calino, who also worked on the study, said: 'The unrest in 1970 and 1983 caused tens of thousands of people to be evacuated from Pozzuoli itself.'
Campi Flegrei covers more than 100 square kilometres (38.6 square miles) outside the western suburbs of Naples.
The researchers predict that an eruption today would affect the 360,000 people living across the caldera and Naples' population of nearly one million.
Professor Giuseppe De Natale, who also worked on the study, said: 'Most damage in previous crises was caused by the seismic shaking of buildings.
'Our findings show that we must be ready for a greater amount of local seismicity during another uplift and that we must adapt our preparations for another emergency, whether or not it leads to an eruption.'
HISTORY OF CAMPI FLEGREI
The Phlegraean Fields, or Campi Flegrei, volcano system has had a colourful history.
The Romans thought an area called Solfatara - where gas is emitted from the ground - was the home of Vulcan, the god of fire.
Meanwhile, one of the craters in the system, Lake Avernus, was referred to as the entrance to Hades in ancient mythology.
Additionally, Campi Flegrei has long been a site of geological interest.
In Charles Lyell's 1830 Principles of Geology, he identified the burrows of marine fossils at the top of the Macellum of Pozzuoli, an ancient Roman market building, concluding that the ground around Naples rises and falls over geological time.
Two eruptions have occurred at the site, one in 1158 at Solfatara and the other in 1538 that formed the Monte Nuovo cinder cone.
But more recently the ground around Naples has shown signs that the supervolcano may be preparing to erupt again.
In 1969-72 and 1982-84 the Earth's crust in the area around Pozzuoli rose by 11 feet in just a few months.
This phenomenon is called bradisism - a slow movement of the earth's surface, as opposed to fast movement due to an earthquake.