On 26th December 2004 off the coast of Northern Sumatra the fourth largest earthquake this century occurred at 00:58 UTC. The quake occurred at 10 km depth, and was measured to 9.0 on the open ended Richter scale. A displacement of the tectonic plates will always generate a wave at the surface of the ocean - a so-called Tsunami. In this case the tectonic plates are estimated to have been displaced as much as 30 meters - the energy thus released being the equivalent of 10.000 Hiroshima atomic bombs
Within 24 hours after the earthquake DHI published the first animations of the associated tsunami based on an operational global model which was refined in the Indian Ocean to produce more detailed information of the wave propagation.
Later on the results were analyzed further and showed excellent agreement with satellite observations. Likewise, subsequent detailed studies of the wave run-up have revealed excellent comparisons between model results and observations.