Since the 1908 event, an estimated 1,000 scholarly papers (most in Russian) have been published about the Tunguska explosion. Owing to the site's remoteness and the limited instrumentation available at the time of the event, modern scientific interpretations of its cause and magnitude have relied chiefly on damage assessments and geological studies conducted many years after the event. Estimates of its energy have ranged from 3–30 megatons of TNT (13–126 petajoules).