Creation of Tsunami Evacuation Time Map for the Mentawai Islands, Indonesia

Abstract

The Mentawai Islands are located offshore of West Sumatra, Indonesia, and are likely to be hit by a large-scale tsunami in the future. In this study, maps showing tsunami evacuation times (ETs) along the road on the Mentawai Islands were developed to mitigate tsunami impact. We define the tsunami ET as the time required for an evacuee to move to a safe location through the road network from the tsunami inundation area. The safe locations were determined using a digital elevation model and the assumed tsunami inundation heights. The closest safe place for each location on the road network was determined using the shortest path search algorithm for the graph network. First, areas with high tsunami risk on the islands were identified using the obtained ET maps. Second, the appropriateness of the evacuation approach in the Matobe village on Sipora Island was evaluated based on the ET maps. Finally, population exposures to the different ET levels were estimated to quantify the potential risk of loss of life to a tsunami disaster in the Mentawai Islands. This study contributes to the tsunami disaster preparation of residents of the Mentawai Islands.