Tsunami Evacuation Planning as a tool for Tsunami Risk Reduction: A case study in Palu Bay, Central Sulawesi

Abstract

Situated in one of the most complicated tectonic zones of the world, Palu is classified as one of the most susceptible places to earthquake and tsunami in Indonesia. This study aim to develop near-field tsunami evacuation simulation, as the primary strategy to reduce casualties in disaster risk reduction, based on daytime and night-time population scenarios in a tsunami-prone area in Palu Bay, Central Sulawesi. Least Cost Distance, a geospatial evacuation analysis approach in ArcGIS, is applied involving three main variables, namely population exposure, the arrival time of tsunami and walking speed of evacuees. These variables were analysed to calculate distribution of populations in daytime and night-time scenario; to identify and calculate the capacity of potential existing evacuation shelter buildings (ESB); and to analyse suitable locations, and to calculate the number and capacity of additional ESBs based on the most effective evacuation route. This study found that of the population in the study area, about 62.60 % cannot be sheltered in the seven existing ESB in the daytime as well as 63.98% of total population in the night-time scenario. Meanwhile,only 60.13% and 61.83% of the population in the service area of existing ESBs, can be evacuated in daytime and night-time scenarios, respectively. Therefore, eleven and twelve additional ESBs are proposed to be established for daytime and night-time scenarios, respectively, to accommodate people who currently cannot be sheltered.