The 2004 Indian Ocean tsunami was a catastrophic event associated with a the 2004 Indian Ocean earthquake, the second largest ever recorded by a seismograph. The earthquake lasted about nine minutes, the longest ever recorded, and had a magnitude on the Richter scale of 9.3, and was the second most severe earthquake since 1737. Its epicenter was off the west coast of Sumatra, Indonesia. The immense amount of energy released caused the 2004 Indian Ocean tsunami, which killed over 225,000 people in eleven countries, and caused waves as tall as 30 m (100 ft). The shaking of the earthquake itself was felt in Bangladesh, India, Malaysia, Myanmar, Thailand, Singapore and the Maldives. The primary force of the tsunami was felt in nations on the coast of the Bay of Bengal, to the east of India.
The 2004 Indian Ocean tsunami was the seventh deadliest natural disaster in history, only being surpassed by one other earthquake, two cyclones, and three floods. The Indian Ocean tsunami destroyed many thousands of homes and left hundreds of thousands of people homeless, mostly in Indonesia, Sri Lanka, India, and Thailand. The international community responded by donating more than $7 billion (2004 U.S. dollars) in humanitarian aid, and flying in supplies via jumbo jets. As of 2008, economic reconstruction in some coastal areas is still ongoing.
The Indian Ocean tsunami was caused by what is called a megathrust earthquake, where one tectonic plate slips beneath (subducts) another. In the 2004 Indian Ocean earthquake, the India Plate subducted under the Burma Plate, over 8 - 10 minutes, across a length 1600 km (1000 mi) long, with a total motion of 35 m (108 ft). This released energy equivalent to 26.3 megatons of TNT, over 1502 times that of the Hiroshima atomic bomb, but less than that of the largest nuclear weapon ever detonated. The event was followed by numerous aftershocks which shook the surrounding area daily for the next three to four months.
