what happened?

The fourth largest earthquake in this century with an epicentre off the coast of Aceh (North Sumatra) awoke the world on the 26th of December 2004 at 00:58 UTC.  The vertical displacement of the earth's tectonic plates ranging up to several meters along an approximately 400 km fault line (ref. http://www.usgs.gov/  - maximum displacement of 20 meters was reported), generated Tsunami waves that hit coastal areas around the Bay of Bengal a few hours later causing extreme loss of human life.

Being closest to the epicentre, the coastal areas in the Northern part of Sumatra were hit almost immediately by the largest waves with devastating effects.
Because of wave reflections caused by the location of the islands, the coastal areas were hit by a series of waves for several hours.

The preliminary simulation that produced this animation shows the propagation of the tsunami starting at 01.00 hours UTC. In the deep ocean the waves measure tens of centimetres in height. In the coastal areas however, these relatively small waves can increase up to 4 to 10 meters depending on the local topography and bathymetry.

Areas hit by high flood waves are shown in bright colours. Yellow and red colours indicate the worst hit areas. The simulation is carried out using the Delft3D simulation package of Deltares.

sharing knowledge

Subsequently, Indonesian agencies were contacted to find out how and if we could assist in the improvement of coastal protection and safety, to efficiently absorb impacts of any future tsunami events. This resulted on the singing of a

Memorandum of Agreement between Deltares, ITB (Bandung Institute of Technology) and BMG (Institute for Meteorology and Geophysics). The objective is to exchange knowledge in order to be able to implement measures in the area affected by the tsunami in both the short and the long term. Within the scope of this agreement, Deltares made its Delft3D software available to both institutes to allow our Indonesian partners to carry out numerical experiments to better understand the dynamics of tsunami generation, propagation and flooding and to support the restoration efforts of habitats (coral reef, mangroves and wetlands).