The probability of community-scale building damage and economic loss in Thailand increased after the 2004 Indian Ocean tsunami

Understanding the impacts of tsunamis, especially in terms of damage and losses, is important for disaster mitigation and management. This study aims to estimate the building damage and economic loss (direct and indirect) changes for two periods before and after the 2004 Indian Ocean Tsunami (IOT) on Patong Beach in Phuket Province, Thailand. We begin to produce the tsunami hazard map using the TUNAMI-N2 model and examine the change in buildings during the two periods. Next, the fragility curve established from the 2004 IOT was applied with the hazard map and construction unit cost to estimate the damage losses as direct losses. Then, we adopt the exogenous multiregional input–output (MRIO) table method to distinguish the indirect regional economic losses throughout the country. Finally, the indirect losses are estimated by using the economic structure based on the MRIO table. Our results show that over a 15-year period, the number of buildings in Patong Beach increased by approximately 30% since the 2004 IOT. The greatest increase was observed for hotels/restaurants (18%), followed by houses (10%). The increase in building density affected the water level, increasing in the area close to the coastline while decreasing in the area far from the coastline. This impact reveals that the mean inundation in the whole area is reduced by 4%. Buildings show higher damage in the area close to the coastline, which increased by approximately 10%. Based on the 2004 IOT, the direct damage losses also increased by approximately 58%, in which the highest direct loss was in hotel/restaurant buildings, followed by stores/warehouses. The indirect losses of the inundated building increased by approximately 55% compared with the direct losses from the 2004 IOT. Among the impacted sectors in the MRIO table, the hotel/restaurant sector suffered the highest losses; within this sector, the fishery sector was most affected, followed by the food production sector and then the crop sector. On the regional scale, Bangkok has the highest impact, with the second-highest impact in the east and the next highest impact in the west. To consider the difference between the two periods, the indirect loss increased by 48% and 43% on the sector and regional scales, respectively. Approximately 55% of the overall economic losses were indirect, including the economic impacts of increased construction in the coastal risk area of Phuket Island on Thailand's economy. This approach could be useful for stakeholders and policymakers for future tsunami mitigation in cases at the community scale.