In late June 2008, Sicily’s Mount Etna was releasing continuous plumes of ash and steam, according to the U.S. Air Force Weather Agency. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terra satellite caught the volcano’s activity in this picture taken on June 21, 2008. The volcano continued releasing plumes in early July.
In this false-color image, made with a combination of visible and infrared light, vegetation appears bright red, bare ground appears charcoal, and the volcanic plume ranges in color from nearly white to pale blue. Signs of past eruptions appear in the rivulets of rock left over from old lava flows that spread out from the summit.
Mount Etna is a stratovolcano composed of alternating layers of hardened lava, solidified ash, and rocks ejected by past eruptions. The plume shown in this image is mild compared to some of Etna’s past activity. Records of the volcano’s activity data back to 1500 BC. At 3,330 meters (10,925 feet) high, Etna towers over Catania, Sicily’s second-largest city.