But very, very slowly.
On the human scale, a movement of 14mm/yr - that is 1.4m over a hundred years - will seem very small, and it is. But geological investigations elsewhere in the world have shown that extinct volcanoes that display this kind of trend can suffer catastrophic failures on their leading flank as they drift downslope. Stresses can build up that lead eventually to devastating landslides.
Dr Murray and colleagues stress such behaviour is very rare and can take many centuries, even thousands of years, to develop to a critical stage. Certainly, there is absolutely no evidence that this is about to happen at Etna. Local residents should not be alarmed, the Open University scientist said.
"The 14mm/yr is an average; it varies from year to year," he explained. "The thing to watch I guess is if in 10 years' time the rate of movement has doubled - that would be a warning. If it's halved, I'd say there really is nothing to worry about."
http://www.bbc.com/news/science-environment-43522169
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