Earth Observations taken by the Expedition 13 crew

ISS013-E-66488 (14 Aug. 2006) --- Ash cloud from Ubinas Volcano, Peru is featured in this image photographed by an Expedition 13 crewmember on the International Space Station (ISS). Subduction of the Nazca tectonic plate along the western coast of South America forms the high Peruvian Andes, and also produces magma feeding a chain of historically active volcanoes along the western front of the mountains. The most active of these volcanoes in Peru is Ubinas. A typical steep-sided stratovolcano comprised primarily of layers of silica-rich lava flows, it has a summit elevation of 5,672 meters. The volcanic cone appears distinctively truncated or flat-topped in profile -- the result of a relatively small eruption that evacuated a magma reservoir near the summit. Following removal of the magma, the summit material collapsed downwards to form the current 1.4 kilometer-wide summit caldera. This oblique image (looking at an angle from the ISS) captures an ash cloud first observed on satellite imagery at 11:00 GMT on Aug. 14, 2006; this image was acquired one hour and 45 minutes later. The ash cloud resulted in the issuing of an aviation hazard warning by the Buenos Aires Volcanic Ash Advisory Center. Modern activity at Ubinas is characterized by these minor to moderate explosive eruptions of ash and larger pumice - a volcanic rock characterized by low density and high proportion of gas bubbles formed as the explosively-erupted parent lava cools during its transit through the air. These materials blanket the volcanic cone and surrounding area, giving this image an overall gray appearance. Shadowing of the western flank of Ubinas throws several lava flows into sharp relief, and highlights the steep slopes at the flow fronts -- a common characteristic of silica-rich, thick, and slow-moving lavas. NASA researchers note that the most recent major eruption of Ubinas occurred in 1969, however the historical record of activity extends back to the 16th century.