Toba Caldera, Sumatra Click Image to Enlarge  (JPG) (4,293,756 bytes) ( 4,285 x 4,501 )

Toba caldera in Sumatra, Indonesia produced the largest volcanic eruption in the last 2 million years. The caldera is 30 by 100 km, and has a total relief of 1700 m. The caldera probably formed in stages: large eruptions occurred 840,000, 700,000 and 75,000 years ago. The eruption 75,000 years ago produced the Young Toba Tuff, with an estimated volume of 2,800 cubic kilometers. By comparison, Mt. St. Helens erupted about 1 cubic km of ash. In places around the caldera, the tuff is more than 600 m thick. Ash fall from the eruption covers an area of at least 4 million square km (about half the size of the US). Toba and other stratovalocanoes in Sumatra are related to the subduction of the Indian Plate under the Eurasian Plate. The ASTER image was acquired on January 28, 2006, covers an area of 64.3 by 67.5 km, and is located near 2.6 degrees north latitude, 98.8 degrees east longitude.