The Toba eruption (the Toba event) was the largest volcanic eruption on Earth in the last 28 million years. To give an idea of its magnitude, consider that although the eruption took place in Indonesia, it deposited an ash layer approximately 15 cm (6 in) thick over the entire Indian subcontinent; at one site in central India, the Toba ash layer today is up to 6 m (20 feet) thick. This article is about volcanoes in geology. ...

The eruption occurred at what is now Lake Toba on the island of Sumatra about 73,000 ± 4000 years ago. It had a Volcanic Explosivity Index of 8, making it the most recent eruption of a supervolcano. Bill Rose and Craig Chesner of Michigan Technological University deduced that the total amount of erupted material was about 2,800 cubic km — around 2,000 km³ of ignimbrite that flowed over the ground and around 800 km³ that fell as ash, with the wind blowing most of it to the west. By contrast, the 1980 eruption of Mount St. Helens ejected less than 1 cubic km of material. View of Lake Toba Lake Toba is a large lake, 100km long and 30km wide, in the middle of the northern part of the Indonesian island of Sumatra. ... Sumatra (also spelled Sumatara and Sumatera) is the sixth largest island of the world (approximately 470,000 km²) and is the largest part of Indonesia. ... The Volcanic Explosivity Index (VEI) was devised by Chris Newhall of the U.S. Geological Survey and Steve Self at the University of Hawaii in 1982 to provide a relative measure of the explosiveness of volcanic eruptions. ... A supervolcano refers to a volcano that produces the largest and most voluminous kinds of eruptions on earth. ... William I. Rose is a professor of minerology, petrology and meteorology at Michigan Technological University. ... Michigan Technological University (abbr. ... Ignimbrite is a compact igneous rock of volcanic origin. ... Mount St. ...

Such a huge eruption probably lasted nearly two weeks. Very few plants or animals in Indonesia would have survived, and it is possible that the eruption caused a planet-wide die-off. There is some evidence, based on mitochondrial DNA, that the human race was reduced to only a few thousand individuals by the Toba eruption (see Toba catastrophe theory). Mitochondrial DNA (mtDNA, or less popularly, mDNA) is DNA which is not located in the nucleus of the cell but in the mitochondria. ... According to the Toba catastrophe theory, modern human evolution was affected by a recent large volcanic event. ...

See also

• List of disasters
• Natural disaster

This is a list of world disasters, both natural and man-made. ... A natural disaster is the consequence or effect of a hazardous event, occurring when human activities and natural phenomenon (a physical event, such as a volcanic eruption, earthquake, landslide etc. ...

External link

• George Weber, "Toba Volcano"