Tata Sabaya, a volcano located in the Altiplano region of Bolivia, rises to a summit elevation of 5,430 meters (17,800 feet) above sea level. While its current form is that of a youthful stratovolcano, the regional geological evidence indicates an older, eventful history.
Prior to 12,000 years ago, a large debris avalanche was formed by the collapse of the ancestral Tata Sabaya volcano. Debris from the avalanche swept into the nearby Salar de Coipasa, significantly changing its northwestern coastline. The timing of the event was obtained from tufa deposits formed on debris islands during a high stand of the Coipasa lake. The sequence illustrates the geological principle of crosscutting, in that the debris avalanche had to have occurred before the tufa deposits were formed in the lake.
The Tata Sabaya stratovolcano is located at image center in this photograph from the International Space Station. Several young lava flows are visible on the northwestern and western flanks of the volcano. Peaks visible to the northeast and southwest appear to be volcanoes as well, but unlike Tata Sabaya, there is no record of recent activity from either of them, according to the Smithsonian National Museum of Natural History’s Global Volcanism Program.
As the climate of the Altiplano became more arid and the Coipasa Lake shrank, much of the hummocky terrain of the debris avalanche became exposed (an area of more than 300 square kilometers, or 116 square miles). The hummocky terrain is clearly visible on the left side of the image. White salt deposits of the salar surround many of the individual hummocks, making them “islands” once again.