For decades, scientists have known that the southeastern slopes of Mount Etna, an active volcano on the eastern shore of Sicily in Italy, are shifting toward the sea about 2 or 3 centimeters each year. Now, they have a better idea of why this is happening, and it’s making them worried.
In a new study, scientists gathered data from seafloor instruments that allowed them to track the movement of the volcano’s submarine slopes over time. For most of the 15-month period they studied, nothing happened. But during an 8-day period in May 2017, Mount Etna’s southeastern flank moved 4 centimeters to the east, the researchers report online today in Science Advances.
That’s a much larger movement than has been recorded on land, suggesting the southeastern flank of the volcano is collapsing under its own weight. There’s no telling whether, or when, this slow-motion landslide will really let loose, but the researchers note that sudden slumps of undersea material have created locally devastating tsunamis in other parts of the world.