Integration of Spatial Analysis for Tsunami Inundation and Impact Assessment

摘要

Disaster mitigation and reconstruction plan due to tsunami can be implemented with various actions. An integration of spatial analysis through Geographical Information System (GIS) application and multi-criteria analysis through Analytical Hierarchy Process (AHP) is one of the methods for tsunami inundation and impact assessment. In this study, vulnerability, inundation and impact assessment due to tsunami hazard in Ofunato city, Iwate Prefecture, Japan was carried out. Appropriate input parameters were derived from Digital Elevation Model data, and satellite remote sensing and field data were analyzed through GIS. We applied the parameter of elevation and slope created from Aster GDEM version 2, coastline distance created from vector map of the study area and vegetation density created from ALOS ANVIR-2 image. We applied AHP process for weighting the parameter through pair-wise comparison using five iterations of normalized matrix. Five classes of vulnerability were defined and analyzed for tsunami inundation mapping. We used weighted overlay through spatial analyst in GIS to create the final map of tsunami vulnerability. The assessment results indicate that 7.39 square kilometer of the study area was under the high vulnerability zone due to tsunami, and 8.13 square kilometer of building area was under the inundation area. Our result showed good agreement with the observed data and historical map. The result presented here can aid as preliminary information for the coastal zone management related to disaster mitigation and for the evacuation process and management strategy during disaster.