Risk Analysis of Coastal Erosion in Mentawai Island, West Sumatra Province, Indonesia

Mentawai Island is adjacent with Indian Ocean that prone to high waves due to the wind in the Australia monsoon periods so that this island affected by coastal erosion. This coastal hazard causes significant risk like physical damage. Accordingly, disaster risk reduction program in coastal areas is indispensable in advance for the next destructive coastal hazard event. This need is answered by conducting disaster risk analysis as the first step in coastal erosion identification in the Mentawai Islands. The risk was obtained using a qualitative approach by combining the multi-dimensional aspects of hazard as well as vulnerability. Hazards aspect was derived from identification of physical variables to erosion and was represented by index value. Vulnerability aspects consist of physical aspect and social aspect. The physical aspect is the distribution of buildings and the social aspect is population density that obtained by modeling process. The result indicated that the eastern Mentawai coast has a wider area of erosion risk than the west coast due to the influence of the Australian monsoon.