I found an interesting article in local [Slovenian] newspaper. This is a short abstract.
The article is titled "Is good mountain turning into a pile of gunpowder (Etna erupts differently)". It explains that Etna erupts approx. 18 times per century, with relatively mild eruptions. Etna's lava is very fluid and most eruptions are simply a "spill over" of lava. That's why locals called it a "good mountain", as that spilled lava, when hardened, is very good as a soil for plants. That was until last year (2001). Last year's, and this year's eruptions were different. Eruptions were more explosive, with more strong earthquakes. Vulcanologists analyzed lava and found that it is no longer so fluid, but more dense. Such denser lava was last found in 15,000 years old layers, when very explosive eruptions occurred (that's when Etna's previous dome collapsed).
Offered by Kiko.
Delo [Work], Sobotna priloga [Saturday's Addition],
November 9, 2002
Is Good Mountain Turning into a Pile of Gunpowder?
References: Der Spiegel, Hamburg