The Toba supereruption (Youngest Toba Tuff) was a supervolcanic
eruption that occurred some time between 69,000 and 77,000 years
ago at Lake Toba (Sumatra, Indonesia). It is recognized as one
of the Earth’s largest known eruptions. The related catastrophe
theory holds that this event plunged the planet into a
6-to-10-year volcanic winter and possibly an additional
1,000-year cooling episode. This change in temperature is allege
to have resulted in the world’s human population being reduced
to 10,000 or even a mere 1,000 breeding pairs, creating a
bottleneck in human evolution. Although the Toba eruption took
place in Indonesia, it deposited an ash layer approximately 15
centimetres thick over the entirety of South Asia. A blanket of
volcanic ash was also deposited over the Indian Ocean, and the
Arabian and South China Sea.