- Campi Flegrei is a supervolcano located outside the western suburbs of Naples
- Its last devastating eruption was in 1538, following a century of unrest
- The volcano has been restless again since 1950, with regular earthquakes
- There is now a build up in energy in the crust similar to the 1538 eruption
- If it does erupt, experts believe it would affect 360,000 people living across the caldera and Naples' population of nearly one million
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 we are 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 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.'