The Southeast Asia tsunamis killed more people than any tsunami ever recorded. The series of seismic waves that rushed across the Indian Ocean on December 26, 2004, caused damage of biblical proportions and prompted a humanitarian rescue and aid effort on an unprecedented scale. That morning a 9.0 earthquake occurred off the northwestern tip of the island of Sumatra, Indonesia. Witnesses to the tsunamis reported that following the earthquake, ocean waters receded from shorelines hours before the giant waves roared in, washing over islands and sweeping through coastal villages in 12 countries, including Indonesia, Myanmar, India, and Sri Lanka. The waves struck as far west as the coast of Africa.

More than 150,000 people died in the disaster; Indonesia’s death toll alone surpassed 85,000. The international response was immediate and reached into the billions of dollars. Nonetheless relief efforts were hampered by remote island locations, the destruction of infrastructure, and ongoing conflicts in some areas. In the weeks following the tsunamis, officials recognized that the true death toll would take time to be known, since survivors had yet to be interviewed about relatives and friends who remained missing. It was expected that many had been washed out to sea and thus had not been counted in the initial death toll, which was based on body counts. A preliminary report from the World Bank put the damages at $4.5 billion in Indonesia alone. But officials acknowledged that it would take months to calculate damages.

The earthquake that struck the morning of December 26, 2004, was the third-biggest earthquake in the past 100 years (and the biggest since 1964, when a 9.2-magnitude temblor occurred off Alaska). Scientists believe that the Southeast Asia quake occurred about 6.2 miles beneath the ocean floor and caused a great protrusion in the sea bed, generating waves that moved across the ocean in the early morning hours. Though probably not huge when they were out at sea, the waves grew higher as they approached shore, as tremendous volumes of water were forced to the surface.