Tsunami Vulnerability Assessment Using GIS and AHP Technique for Southern Coastal Region of India

A tsunami is a sequence of powerful waves or surges primarily resulting from underwater earthquakes. Creating tsunami vulnerability maps is of utmost importance to develop effective strategies for mitigating potential damage caused by future tsunamis. This article focuses on areas (Indian subcontinent) severely affected by the 2004 Indian Ocean tsunami. Utilizing geographic information system (GIS)-based tools, the authors employed geospatial cell-based modeling and used a multicriteria decision-making tool, an analytical hierarchy process (AHP), to develop the final inundation map. Using the digital elevation model and Environmental Systems Research Institute (ESRI) land-cover data, the authors created the elevation, slope, coastal proximity, flow accumulation, and land-use land-cover (parameters) map. Areas with a higher risk of tsunami impact are predominantly situated along the coastline with a descending terrain. The presence of waterways and lower elevations intensifies the impact of tsunamis. Regions classified under very high or high vulnerability are more likely to be inundated by the tsunami. The final vulnerability map of Nagapattinam shows that $166.455{\mathrm{km}}^2$ of the region is highly vulnerable to a tsunami. Similarly, Kanyakumari, Cuddalore, Karaikal, and Chennai show $37.6516{\mathrm{km}}^2$, $245.641{\mathrm{km}}^2$, $35.7128{\mathrm{km}}^2$, and $35.6306{\mathrm{km}}^2$, respectively, under very high vulnerability. The findings of this study serve as fundamental information for disaster mitigation and urban planning in coastal regions. The research introduces a novel approach to assess areas susceptible to tsunami inundation, utilizing a vulnerability map generated through remote sensing and spatial multicriteria analysis. Furthermore, the parameters employed closely resemble those used in actual inundation mapping, adding to the practicality and reliability of the results. Village maps of the selected area are superimposed on the final vulnerability map to understand the villages vulnerable to tsunamis better. The final vulnerability maps can be used for strategic mitigation during an actual event and to be prepared for future disasters.