A teraton is the equivalent, in SI terms, of being 1.00×1012 tons; 1,000 gigatons; 1,000,000 megatons; 1,000,000,000 kilotons; or 1,000,000,000,000 tons (one trillion tons) in its entirely expanded form.
The energy released by the explosion of one teraton of TNT, 4.18×1021 joules, is equivalent to the energy of an earthquake of magnitude 10 on the Richter Scale, or to the energy of a 2 km rocky meteorite impacting the earth at 25 km/s.