On the morning of December 26, 2004, the earth's crust tore open. Off the coast of northern Sumatra, a 1,300-kilometer stretch of the Sunda megathrust fault ruptured. It triggered a colossal earthquake, registering between 9.1 and 9.3 in magnitude. For nearly ten minutes, the longest duration ever recorded, the ground shook with the energy of 23,000 Hiroshima-type atomic bombs. The seafloor was thrust violently upwards, displacing 30 cubic kilometers of water. This single event, deep beneath the Indian Ocean, set in motion the deadliest tsunami in recorded history. The entire planet was jolted by the impact, vibrating by up to 1 centimeter, as a wave of unimaginable power began its silent journey across the sea.
The Boxing Day Tsunami
How the December 2004 Sumatra earthquake set off the deadliest tsunami on record, what happened from Aceh to Thailand and Somalia, and the Indian Ocean warning system built afterwards.
Chapter 1
The Rupture
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Frequently Asked Questions
What caused the 2004 Indian Ocean tsunami?
A massive 9.1 to 9.3 magnitude earthquake struck off the coast of Sumatra, Indonesia. The rupture of a 1,300-kilometer fault line pushed the seafloor upwards, displacing about 30 cubic kilometers of water and creating the tsunami waves.
Why was there no warning for the tsunami in the Indian Ocean?
At the time, no coordinated tsunami warning system existed for the Indian Ocean. The Pacific Tsunami Warning Center detected the quake but had no official mandate, deep-ocean sensors, or established communication channels to alert the affected countries.
What was the most important change made after the 2004 tsunami?
The creation of the Indian Ocean Tsunami Warning and Mitigation System in 2005. The system uses deep-ocean buoys and seismometers to provide rapid, real-time alerts to coastal nations, a measure that did not exist before the disaster.
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