The Supervolcano of Lake Toba
Lake Toba fills the crater of the largest eruption of the last two million years, which may have nearly wiped out humanity.
What was reported
Lake Toba in Sumatra, about 100 km long, fills the crater left by a colossal eruption around 74,000 years ago, thousands of times larger than the 1980 eruption of Mount St Helens. Its ash fell as far away as India.
In the 1990s scientists proposed the Toba catastrophe theory: that the eruption caused a volcanic winter that shrank the human population to a few thousand people, a bottleneck some saw in our DNA.
Explanations offered
Later studies have challenged this. Stone tools in India appear both below and above the Toba ash, suggesting people survived there, and evidence from Africa suggests life went on. Many researchers now think the effects, though severe, weren't catastrophic for humans. The debate continues.
- When
- Erupted about 74,000 years ago
- Where
- Lake Toba, North Sumatra, Indonesia
- Witnesses
- Geologists
- Status
- Disputed
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.