The interaction of the African and Eurasian Plates is complex, with areas of compression, subduction and transform-faulting (lateral slippage and scraping). Mt. Etna, Europe's tallest and most active volcano, rises near the east coast of Sicily and has developed along a subduction zone, where the African Plate is dipping beneath the Eurasian Plate; there is some debate among geologists whether its formation is strictly due to melting of the African Plate as it subducts or whether a fracture developed within the plate, producing a local hotspot.
Towering to almost 11,000 feet, Mt. Etna began to form about 500,000 years ago, initially as a shield volcano that built up from repeated flows of basalt; very late in the Pleistocene, about 35,000 years ago, it converted to a stratovolcano, rising to much greater heights. Several eruptive craters are clustered near its summit but many more are scattered along its flanks; indeed, a massive eruption on its eastern slope produced the Valle de Bove, a giant gash similar to that which resulted from Mt. St. Helen's eruption in 1980.
After continuously erupting from 1979-1992, Mt. Etna has entered a quieter phase but periodic eruptions of ash or lava continue, as is occuring this week. While those who live around this majestic peak benefit from the region's fertile volcanic soils, they face the ongoing threat of another catastrophic eruption. As for those who reside along other active plate boundaries, it is not a matter of if, but when, such an event will occur.
