Looking in the past to predict the next tsunami

Undersea earthquakes cause tsunamis which deposit enormous amounts of sediment along coastlines, and that could offer scientists a clue as to when the next disaster might strike.



“Giant earthquakes repeat so you can predict future occurrence from past records,” writes Kenji Satake of the Earthquake Research Institute at the University of Tokyo in Japan. 



Geologists have deciphered layers of sand sheets dating back a few centuries in tsunami-prone Indonesia and Sri Lanka. We now know that the 2004 Indian Ocean tsunami, which left 226,408 dead, has a predicted return period of 520 years, according to Hazmah Latief, a tsunami expert at the Bandung Institute of Technology in Indonesia, whose work is cited in the Asia Pacific Disaster Report.



 He has calculated that tsunamis took place in Aceh and Meulaboh in Indonesia between AD 1290 and 1400, and have recurred every 600-1,000 years in Sri Lanka. However, effective earthquake and tsunami prediction appears still to be a long way off. The 7.7 Richter scale earthquake which struck Indonesia's Kepulauan Mentawai region off western Sumatra this week was not predicted: It left more than 400 dead.



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