Verification of the destruction mechanism of structures in Sri Lanka and Thailand due to the Indian Ocean tsunami

We surveyed disaster situations in the west coast of Thailand and the south coast of Sri Lanka where damage due to the Indian Ocean tsunami of December 2004 was severe, and investigated the destructive mechanism of structures due to the tsunami. The results we obtained were as follows: (1) If a tsunami with a ground-level inundation depth of more than two meters attacks a lowland extending several hundred meters or more inland, severe disaster will occur. In this case, mortar and brick buildings 30 cm or less in thickness will be destroyed. (2) The stability of a building can be estimated using the easy stress calculating method by assuming a gatetype Rahmen building model and calculating dynamic water pressure. (3) Destruction of revetments and seawalls is caused by incident wave pressure or return flow. In this case, the stability of a coastal structure is mainly determined by the balance of water pressure and earth pressure.