Suphat Vongvisessomjai and Pornsak Suppataratarn

pp. 929 - 942

Abstract

A catastrophic tsunami on December 26, 2004 caused devastation in the coastal region of six southern
provinces of Thailand on the Andaman Sea coast. This paper summaries the characteristics of tsunami with
the aim of informing and warning the public and reducing future casualties and damage.
The first part is a review of the records of past catastrophic tsunamis, namely those in Chile in 1960,
Alaska in 1964, and Flores, Java, Indonesia, in 1992, and the lessons drawn from these tsunamis. An analysis
and the impact of the 2004 Sumatra tsunami is then presented and remedial measures recommended.
Results of this study are as follows:
Firstly, the 2004 Sumatra tsunami ranked fourth in terms of earthquake magnitude (9.0 M) after
those in 1960 in Chile (9.5 M), 1899 in Alaska (9.2 M) and 1964 in Alaska (9.1 M) and ranked first in terms of
damage and casualties. It was most destructive when breaking in shallow water nearshore.
Secondly, the best alleviation measures are 1) to set up a reliable system for providing warning at
the time of an earthquake in order to save lives and reduce damage and 2) to establish a hazard map and
implement land-use zoning in the devastated areas, according to the following principles: - Large hotels located at an elevation of not less than 10 m above mean sea level (MSL)
- Medium hotels located at an elevation of not less than 6 m above MSL
- Small hotel located at elevation below 6 m MSL, but with the first floor elevated on poles to allow
passage of a tsunami wave
- Set-back distances from shoreline established for various developments
- Provision of shelters and evacuation directions
Finally, public education is an essential part of preparedness.