A massive volcano is sliding into the sea

A massive volcano is sliding into the sea
A massive volcano is sliding into the sea. History shows that could be catastrophic.

Sicily’s Mount Etna is one of the world’s most active volcanoes, but scientists say eruptions aren’t the only major threat posed by this smoldering peak.

A new study shows that Etna is slowly sliding toward the sea, raising the prospect that it may suddenly collapse and trigger a massive tsunami that could devastate the region around the Eastern Mediterranean Sea.

Etna is a big and heavy volcano, so gravity is pulling it down,” Morelia Urlaub, a research scientist at the GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany, and the study’s lead author, told NBC News MACH in an email. “It can spread more easily towards the sea as there is nothing to 'stop' it.”

The volcano’s slow subsidence has been known since the 1990s. But Urlaub and her colleagues used a network of underwater sensors along the volcano’s southeastern flank to get a detailed look at its movement.

Etna typically moves about 2 to 3 centimeters (about 1 inch) per year, according to Urlaub. In the recent study, published Oct. 10 in the Journal Science Advances, the sensors showed that Etna’s creeping motion occasionally speeds up for weeks or months at a time as molten rock (magma) builds up underground before spewing out in an eruption; in 2017, the sensors detected a slip of 4 centimeters (about 2 inches) over eight days, without an associated eruption.