Tsunami modelling and risk assessment of Hambantota, Sri Lanka using integrated remote sensing techniques

Abstract

This study was carried out to develop an inundation and risk assessment model in Hambantota coastal area, based on the 2004 tsunami event. This tsunami event was one of the largest tsunamis to cause devastation to human beings, livelihoods, buildings, roads, rails and other infrastructure facilities in the study area. In addition to this study area, other parts of the coastal belt of Sri Lanka also experienced the chaotic outcomes of this tsunami event. By modelling risk, based on the 2004 tsunami event data, inundation and risk assessment for future tsunami event was modelled with a high safety factor. INSPIRE web portal which has been developed based on the TUN AMI mathematical model, was employed in this study to evaluate both inundation and risks to the local communities and their livelihoods with a higher level of accuracy. The main inputs to INSPIRE are topography data/bathymetry data, vulnerability data and fault parameters of the source earthquake, whereas the output maps provide the inundation area, wave velocity along the terrain and the potential risk to the area under consideration. Results of the study represent the variation of the tsunami inundation and the risk assessment of the Hambantota area based on remotely sensed digital elevation data inputs with different spatial resolutions data such as, ASTER, SRTM, LiDAR and GEBCO. Different inundation output maps were analyzed and the risk prone areas were identified. Furthermore, building structures were assigned risk indices based on the vulnerability to damage and fragility curves were developed in the case of a future tsunami event.