from Wikipedia

From the Wikipedia entry about the 2004 Indian Ocean Earthquake:
The total energy released by a magnitude 9.0 earthquake exceeds the total amount of energy consumed in the United States in one month, or the energy released by the wind of a hurricane like Hurricane Isabel over a period of 70 days. Using the mass-energy equivalence formula E = mc2, this amount of energy is equivalent to a mass of about 100 kg (220 lb) (much more than is actually converted to energy in a nuclear explosion), or enough to boil 5000 litres (1,300 US gallons) of water for every person on Earth.