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  December 26 Tsunami in Indian Ocean  


 

The great earthquake (Mw 9.0) of December 26 off Sumatra generated the tsunami in the Indian Ocean. According to U.S.G.S., the aftershocks extended as far as 1,000 km toward north (the red circles indicate aftershocks occurred within 24 hours). Assuming that the aftershock area represents the tsunami source, the tsunami propagation was computed.


 

Tsunami Travel Time (Hours)

Fig1. Tsunami Travel Time


Tsunami Travel Time (in hours) for the entire Indian Ocean

Fig2. Tsunami Travel Time for the entire Indian Ocean


 

The above figures show that the tsunami reaches Phuket and Sri Lanka coasts in two hours after the earthquake, and African coast in 8-11 hours.

The tsunami propagation is also animated (up to 5 hours) from a 1200 km fault. The red color means that the water surface is higher than normal, while the blue means lower. It indicates that initial tsunami to the east (e.g., Phuket) began with receding wave, while to the west (e.g., Sri Lanka) large wave suddenly reached. The darker the color, the larger the amplitude. The tsunamis were larger in the east and west directions.

Click Here for Animation


 

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National Institute of Advanced Industrial Science and Technology

Active Fault Research Center