Italy’s Mount Etna is currently in a period where short bursts of activity, each lasting a few hours, are interspersed with quiet periods lasting several days or weeks. Thirteen eruptive episodes, or paroxysms, had occurred by mid-September 2011.
During a typical paroxysm, lava fountains at the New Southeast Crater send flows down the eastern slope of the volcano, often accompanied by a dense ash plume.
According to the Istituto Nazionale di Geofisica Evulcanologia, “Etna is the largest and tallest volcano of Europe, and one of the most active volcanoes on the Earth. Its eruptions occur both at the summit, where currently there are four craters, and from its flanks, down to a few hundred meters above the sea-level. Summit activity can go on virtually continuously for many years or even decades, but it also often occurs during the intervals between flank eruptions
“New studies have revealed that this volcano is capable of producing violently explosive activity, like the Plinian eruption of 122 B.C. (B.C.E.). In recent years, especially since the late 1970s, there has been a significant increase in the frequency of explosive eruptive episodes, foremost at the summit craters. In particular, the summit eruptions of 1995-2001 included about 150 episodes of lava or fire fountaining (such episodes are often referred to as paroxysms), many of which generated tall columns of ash and gas.
The flank eruptions of 2001 and 2002-2003 have demonstrated that significant amounts of pyroclastic material (ash, lapilli, bombs, and blocks) can be also generated by flank eruptions. Differently from the usually short-lived summit paroxysms, pyroclastic fallout during flank eruptions can go on for weeks or even months, and impact life in the populated areas, besides representing a serious threat for traffic both on the ground and in the air.
Thanks to Wanda for this link