TSUNAMI DAMAGE ESTIMATION IN ESMERALDAS, ECUADOR USING TSUNAMI FRAGILITY FUNCTIONS
Supervisor: Shunichi KOSHIMURA
For the purpose to estimate a probable impact from a tsunami to a populated area located along the Ecuadorian coast, two main steps were carried out. The first step was to run a tsunami numerical simulation considering the seismological and tectonic aspects of the area. In the second step, fragility functions (FF) from a previous research were used in order to calculate the damage probability in the study area. During the process we tried 16 cases of source models with slightly different fault parameters and finally selected one of those as the worst scenario of tsunami inundation. The scenario found as the worst case was a hypothetic case for the earthquake (Mw 8.7) located in front of Esmeraldas city, around 100 km offshore, approximately along the Peru – Colombia trench, with three shallow fault segments (top depth of 10 km), the strike aligned with the trench axis, a middle dip angle of 28o, assuming the large slips of 5 to 15 m, with the rake angle of 90o. The results obtained from the numerical simulation were comparable to a similar study done previously and with those historically documented data. The tsunami damage estimation using FFs resulted in estimated damages of 50% and 44% in exposed buildings and population, respectively. Results also showed that the most impacted areas are located next to the coast shoreline and river, and considering the type and conditions of walls, the level of building damage could be different. The results obtained using tsunami FFs from Banda Aceh, Indonesia are presented as a reference for future detailed analysis, because the numerical simulation has its particular limitations and we used the other country’s FFs from a different event and characteristics of building structures and population. They are limited due to the quality of the data of buildings and population available at present in Ecuador archives, as well.