A spatial analysis of the December 26th, 2004 tsunami-induced damages: lessons learned for a better risk assessment integrating buildings vulnerability.

International audienceThe December 26th tsunami of 2004 caused an unprecedented disaster in the Indian Ocean. In Sumatra, a third of the Banda Aceh area was destroyed and 70,000 people died. The Tsunarisque Program e a FrencheIndonesian research project e brings new considerations to tsunami dynamics and damage intensity in this urban area: An original method of damage spatial analysis is based on field surveys, photo interpretations and GIS. The first result is a very accurate cartography of the tsunami breaking zone that is shown by a steep drop in the damaging gradient around 2.7 km from the coast. The second is a new “macro-tsunamic” intensity scale based on special typologies of buildings and damages. This analysis is complemented by fragility curves that give the statistical relationships between mean damage intensities and wave heights. These results will allow developing application in tsunami potential losses modelling