Super-Eruptions and the Search for Extraterrestrial Intelligence (SETI)

Abstract

Volcanic super-eruptions that produce >1000 km3 of ejected material and ≥ 1000 Mt (1015g) of stratospheric aerosols and sub-micron dust may be capable of creating global climatic disturbances sufficient to cause a severe setback or crash of modern civilization. Eruptions of similar magnitude are estimated to occur on average about every 50000 to 100000 years, which may be considerably more frequent than impacts by asteroids and comets that could cause similar climatic disasters. Prediction, prevention, and mitigation of global volcanic climatic disasters are potentially more difficult than planetary protection from large impactors, so that volcanism might provide an ultimate limit on the longevity of technological civilizations. If the lifetime of technological civilizations were limited to less than 50 000 years by volcanism, then the number of communicative civilizations in the Galaxy might be less than 1 per 10 million stars. Thus, super-eruptions on geologically active, habitable planets may strongly affect the prospects in radio telescopic SETI.