Spatial multi criteria approach for tsunami risk assessment

Abstract

Tsunami risk is defined as mathematical product between vulnerability and hazard. Tsunami risk also refers to the estimated loss from a given hazard to a given element at risk, and it is defined as a combination of tsunami hazard, tsunami vulnerability, exposure, and event probability. Besides tsunami vulnerability, tsunami risk is assessed by a number of criteria. This study applies the combination of element at risk to assess tsunami risk area along coastal area of East Java Indonesia. The study introduces the spatial multi-criteria analysis into tsunami risk assessment along with the existing perspective evolving the role of GIS. In this study, the existing vulnerability parameter was analysed and evaluated. The analysis was done using GIS-based spatial multi criteria approach. All parameter were analysed through weighted overlay using analytical hierarchy process and geospatial analysis. The results are provided as thematic maps of tsunami vulnerability map and tsunami risk map. Tsunami risk maps as a result from this study illustrate five levels of risk from very low to very high based on geospatial analysis. It describes that coastal area with low elevation was at high risk to tsunami, similar to that indicated in tsunami vulnerability map. Coastal area with high density of vegetation describes a low level tsunami risk. The existence of river and other water stream along coastal area are also important parameters in generating tsunami risk map. Risk map highlights the coastal areas with a strong need for evacuation capacities, including evacuation route and evacuation building.