Europe’s largest active volcano is slipping into the ocean, sparking concern it could cause a massive tsunami.

Scientists investigating Mount Etna in Sicily believe the current slow movements could accelerate.

The study by the Geomar Helmholtz Centre for Ocean Research in Germany measured its advance through underwater pressure sensors.

It concluded that one day Mount Etna will collapse into the Ionian Sea, putting communities around the Mediterranean region at risk.

Such an event would see falling volcanic debris causing giant waves and potentially trigger a tsunami.

A spectacular night-time photo of Mount Etna exploding last year. (AP)

But researchers are unable to tell whether this will happen in years or centuries.

Previous studies indicated Mount Etna’s movement was confined to its summit through the effect of magma swirling inside the volcano.

But analysis of the sea bed from pressure sensors around the site showed the volcano’s sliding movements are over a far wider area.

“Mount Etna is huge. It’s over 3000m high and it rises up from below sea level,” Dr Morelia Urlaub, of the Geomar Helmholtz Centre for Ocean Research in Germany, told the Independent .

Smoke pours from the summit of Mount Etna in Sicily. (AP)

“It’s really heavy, and it grows continuously.”

Dr Urlaub said the landslide is advancing at a snail’s pace of 4cms in 15 months, “but there is a danger that it could accelerate and form a landslide that moves really fast into the sea”.

While the information gives scientists a better idea of Mount Etna’s movements, he said predicting when it collapses remains difficult.