The 2004 Sumatra earthquake occurred off the west coast of Sumatra, Indonesia on December 26th. It was one of the largest earthquakes ever recorded, with a magnitude of 9.3. The earthquake triggered a devastating tsunami that spread throughout the Indian Ocean and affected many countries. Over 230,000 people were killed in 14 countries as a result of the earthquake and tsunami. The earthquake was caused by subduction along the boundary between the Indian and Burma tectonic plates.