A 4.8-magnitude earthquake hit the area around Europe’s most active volcano Mount Etna early Wednesday, injuring four people, damaging old buildings and forcing the closure of part of a highway running along the sea, Italian civil protection authorities said.

The quake was the strongest in the region after Mount Etna erupted on Monday, spewing ash and forcing the temporary closure of Sicilian airspace. A series of tremors followed, but the latest one was the strongest.

The national institute for geophysics and vulcanology (INGV) said the quake happened in the middle of the night and was only one kilometre deep.

Despite the closure of a part of the highway running along the coast, the airport at the eastern city of Catania, the capital of the province, was open.

The epicentre was located north of Catania and several families had to spend the night in the streets. Four people suffered light injuries, officials said.

Two people were rescued from a collapsed building.

Monday’s eruption occurred on the side of Mount Etna and was the first lateral eruption in a decade.

Mount Etna is 3,300 metres high with frequent eruptions recorded in the past 2,700 years.

Its most recent eruptions occurred in the spring of 2017 and its last major eruption in the 2008/2009 winter.

At the end of March a study published in the Bulletin of Volcanology said Etna was slowly sliding towards the Mediterranean — at a constant pace of 14 millimetres per year.