Supereruptions as a threat to civilizations on earth-like planets

The largest explosive volcanic eruptions (supereruptions) produce > 1000 km(3) of ejected material and greater than or equal to 1000 Mt (10(15) g) of submicron atmospheric aerosols and dust. These eruptions may be capable of creating global climatic disturbances sufficient to cause severe problems for world agriculture and modern civilization. Supereruptions are estimated to occur on average about every 50,000 years, which is about twice the frequency of impacts by comets and asteroids > 1 km diameter predicted to cause similar climatic effects. Prediction, prevention, and mitigation of global volcanic climatic disasters may be potentially more difficult than planetary protection from the threat of large impacts, so that explosive volcanism might limit the longevity of technological civilizations. (C) 2002 Elsevier Science (USA).