Assessment of Tsunami Hazard Vulnerability along the coastal environs of Andaman Islands

Abstract

The December 2004 Sumatra–Andaman earthquake emphasized consistent and comprehensive assessment of areas that are prone to the hazard of Tsunami. It also focused attention on the hazards that could be posed by large subduction zone earthquakes and the Tsunamis that could be further generated. Due to the extremely high vulnerability in the Andaman Islands in South East India, it is essential for planners to develop a comprehensive a priori information database in order to minimize the impact of these destructive situations. A similar effort has been done in this study wherein the entire Andaman Islands have been assessed to target “Tsunami Hazard Vulnerable areas” in accordance with the maximum wave run-up heights and topography. These areas have been extracted from the total area keeping in mind the run-up wave heights on the very day of the Sumatra–Andaman earthquake, i.e., on December 26, 2004. Also, the topographic variations in the region have been studied to establish a relation between the vulnerability of an area and its topography. The hazard of Tsunami puts at threat, the lives of approximately 314,084 people over an area of 5,833.1 km2 in the Andaman Islands. Out of the total area, 708.8 km2 is the hazardous portion which is 12.1 %. The islands have experienced a total of 386 earthquakes (above 5.0 magnitude) from the time of Sumatra–Andaman Tsunami till the end of 2009. These statistics clearly indicate the need for hazard preparedness and planning in order to minimize impact during unfortunate circumstances. This study thus aims at the preparation of Tsunami Hazard Vulnerability Map for the Andaman Islands which can be further used by administrative and disaster mitigation organizations as and when required.