One of the most powerful earthquakes to hit Naples in decades has rocked the Italian city and surrounding region 'like a bomb', sending people running into the streets.

Local residents reported hearing a 'roar' and feeling a 'strong tremor' as the 4.6-magnitude quake struck at around 9.15am.

The epicentre of the earthquake was just off the coast of the highly active Phlegraean Fields, a volcanic caldera west of the city, at a depth of 1.5 miles.

Multiple people living nearby in the seaside town of Bagnoli said it 'seemed like a bomb' had gone off when the quake hit.

It measured the same magnitude as an earthquake recorded in the region on March 13, the strongest to hit the region in 40 years.

'We rocked a lot... I'm still shaking,' one woman, living in the Vomero district of the city, told La Repubblica.

Another local, who lives in the western Fuorigrotta suburb, described the experience as 'terrifying'.

Rail traffic has been temporarily suspended in the city, which is home to more than 900,000 people.

No injuries or significant damage have been reported so far, with emergency services assessing he situation in various municipalities this morning.

The tremors are part of a seismic swarm, with observers detecting a dozen since just before 9 o'clock this morning and warning that more events cannot be ruled out.

The Vesuvius Observatory also recorded a series of small earthquakes overnight, each no greater than magnitude-1.

The temblor, of the same magnitude as one that occurred in March and May 2024, was the strongest since the region began scientifically recording quakes some 40 years ago.

The most violent earthquake to hit the southern Italian city in recent times - a 6.9-magnitude earthquake in November 1980 - claimed 2,734 lives.

The devastating quake also injured more than 8,800 people and laid waste to more than 300 municipalities.

The March 13 earthquake which struck the city was initially recorded as being a magnitude of 4.4, but this was later revised to 4.6.

The powerful quake, which struck overnight, lasted about 20 seconds and awoke the entire city and large parts of the surrounding region.

Firefighters in the western municipality of Pozzuoli pulled an injured woman from the rubble after the ceiling in her house collapsed.

There was damage to homes and cars as rocks fell from the facades of the city's old buildings.

As with this morning's quake, the epicentre was recorded in the Phlegraean Fields area, beneath which there Europe's largest active volcanic caldera - the hollow left after an eruption.

The Phlegraean Fields is an area of ancient volcanos which is seismically and volcanically active.

Seismologists have said the latest earthquakes in the Phlegraean Fields area are part of a 'bradyseismic crisis' - which sees the earth slowly rise and fall and has been ongoing since 2005.

This happens when magma and gas build up underground, pushing the surface up or letting it sink back down.

Experts say the increase in earthquake activity usually proceeds volcanic eruptions, as underground pressure builds up.

Small quakes can weaken the rock above the volcano's magma chamber, making it easier for magma to push through.