evidence: Etna has released some 40 million cubic metres of volcanic material, says volcanologist Boris Behncke, who monitors Etna closely for the National Institute of Geophysics and Volcanology (INGV). [...] Watching Etna's destructive power [...] Etna is no stranger to these episodes. Despite the extraordinary amount of volcanic material that has erupted, experts agree the volcano is merely repeating previous patterns of behaviour. But they also admit that the power released is greater than before.