A decade after a series of eruptions forced evacuations from the flanks of Mount Etna in Sicily, the volcano is acting up again. This amazing video shows the new flows:
Mount Etna is an enigmatic volcano. It doesn't fall neatly into any of the three major categories of volcanoes—the quiet rift volcanoes that occur where tectonic plates are moving apart, the extremely dangerous subduction-zone volcanoes where the plates come together, or hot-spot volcanoes caused by currents of liquid mantle coming up from deep within the Earth, explained the vulcanologist Tom Pfeiffer in the April 2003 issue of Scientific American [subscription required]. Because it's not in a subduction zone, it doesn't threaten to violently erupt in the way that Mount St. Helens in Washington or Mount Pinatubo in the Philippines have. Still, you wouldn't want to get too close to the edge. Pfeiffer recounted one scary encounter from February of 2000, while standing with a group of spectators 800 meters away from the rim:
After a few minutes, the first red spots began dancing above the crater, rising and falling back into it. The explosions grew stronger, first slowly, then with breathtaking speed, throwing bombs more than 1,000 meters above the rim. Soon the volcanic cone surrounding the crater was covered with glowing rocks. At the same time, a fountain of lava started to rise from a fracture on the flank of the cone. Several other fountains rose from the crater and formed a roaring, golden curtain that illuminated the scene like daylight. Some larger lava bombs crashed into the snow not far from us, but we felt secure in our viewing position. The fountain was nearly vertical, and a strong wind carried the mass of glowing lapilli and ash gently away from us.
Suddenly the lava fountain changed direction, sending a lateral outburst straight toward us. Just in time we reached the shelter of an abandoned mountain hut with a thick concrete roof. A heavy rain of incandescent stones fell around us; lava bombs of all sizes tumbled down, spraying thousands of sparks. Fortunately, our shelter was not hit by anything large, although a two-meter-wide bomb plunged into the snow nearby.