Estimating Impacts of Tsunami on Buildings around Ambon Bay of Indonesia

Ambon is a city situated inside a long bay in eastern part of Indonesia. The city has been stricken by a number of tsunamis in the past. The last tsunami event was generated by a submarine landslide inside the bay that hit two villages in the city in 1950. Despite the long story of tsunamis inside the Ambon city, no study has been conducted to estimate the impacts of future tsunamis on the growing coastal area of Ambon. This study was aimed at assessing the building vulnerability in Ambon due to projected impacts of future tsunamis. A numerical simulation was performed to generate tsunami inundation areas in the city using Cornell Multi Grid Coupled Tsunami Model (COMCOT) based on maximum fault area in the segment. A series of field works to classify the building types in the city were performed in May 2023 on around 70,000 units of buildings along the bay of Ambon. The classifications were done using Hazard United States (HAZUS) frameworks. Tsunami fragility curves were used to estimate the impacts of the tsunami based on flow depths obtained from the numerical simulations. Based on the surveys, this study found that buildings within 200 m from coastline of the bay could be in Damage State 4 (DS4) which is the most severe impacts of tsunamis on buildings.