AN EARTH-SHATTERING KABOOM: What’s so super about super-volcanoes? “The largest known supereruption in the last 25 million years was caused by plates shifting in Lake Toba in Sumatra, Indonesia. This supervolcano erupted 74,000 years ago, ejecting 2800 cubic kilometers of volcanic debris—approximately the volume of Lake Ontario—and plunging the earth into a six-to-10-year volcanic winter. Scientists speculate that this supereruption may have whittled down the human population to a few tens of thousands.”