Near the southern tip of South America, a trio of volcanoes lines up perpendicular to the Andes Mountains. The most active is the westernmost, Volcán Villarrica, pictured in this photo-like image from the Advanced Land Imager on NASA’s Earth Observing-1 (EO-1) satellite on May 15, 2010.
The 2,582-meter (9,357-foot) stratovolcano is mantled by a 30-square-kilometer (10-square-mile) glacier field, most of it amassed south and east of the summit in a basin made by a caldera depression. To the east and northeast, the glacier is covered by ash and other volcanic debris, giving it a rumpled, brown look.
The western slopes are streaked with innumerable gray-brown gullies, the paths of lava and mudflows (lahars). Beyond the reach of ash and debris deposits, the volcano is surrounded by forests; the area is a national park. The biggest recent eruption was in the early 1970s; lava flows melted glaciers and generated lahars that spread at speeds of 30–40 kilometers per hour (20-30 mph) toward Lago Villarrica (visible to the northwest in large image) and southwest toward Lago Calafquéen (lower left).
NASA Earth Observatory image by Jesse Allen and Robert Simmon, using EO-1 ALI data provided courtesy of the NASA EO-1 team. Caption by Rebecca Lindsey.