The Indian Ocean earthquake in 2004 off the West Coast of Sumatra measured 9.2 on the Richter scale. It was the third-largest ever recorded and the amount of energy the undersea earthquake released was 1,500 times that of the Hiroshima atomic bomb. The abrupt vertical movement in the seabed caused by the earthquake unleashed massive seismic tidal waves, which killed 230,000 people in 14 countries on the Indian Ocean. Tsunami waves were observed on shores as far as South Africa and Antarctica. The event is one of the deadliest natural disasters in history.