Remote sensing and GIS approach for Tsunami damage assessment - a case study

Abstract

Tsunami cause widespread damage to the properties as well as human lives in the coastal regions. Sri Lanka is a vulnerable country for tsunami since Java-Sumatra is a very active subduction zone, where there were several very large earthquakes, during the last three years. Current study investigated the potential of remote sensing and GIS in damage detection after a hazardous event. The case study was carried out at Galle, Sri Lanka and the primarily focus was on identification and assessment of damage due to tsunami in 2004. The gravity of damage could not be identified only with the satellite data always, therefore GIS data and field observations had to be employed in such situations. A field survey was carried out to identify the damaged areas and to investigate the existing situation at present. There is an extensive need for a proper evacuation plan for the country. An evacuation plan was also developed for the Gall city using the road map. Schools and religious places such as temples and mosques near to coastal line were used as gathering places. Using the Contour map of the area, high elevation points were identified as evacuation places. The shortest path to evacuation places from the gathering places were calculated using Arc View Network Analyst Extension. Local authorities can use the proposed evacuation plan and maps to minimise the damage in a possible future tsunami event.