Tsunami Vulnerability Assessment of Grand Bay, Mauritius, Using Remote Sensing and Geographical Information System (GIS)

Abstract

Small island countries located in the Indian ocean are mostly vulnerable to tsunamis generated from the Makran and Sumatra earthquake sources. A minor inundation was experienced from the 26th December 2004 tsunami caused by the Sumatra Andaman earthquake while the close island of Rodrigues recorded relatively high surges within its coasts. As a tourist destination for its sandy beaches and blue lagoons, most hotels and foreign invested real estates are located mostly within the coastal region, making the Mauritian economic mainstay vulnerable to the slightest tsunami threat. This research study therefore aims at assessing the vulnerability of the northern region of Mauritius namely Grand Bay, under a possible tsunami threat. Assessment has been categorised in three main vulnerability areas namely the building and infrastructure vulnerability, the human life vulnerability and the environmental vulnerability. The methodology set up includes digitalisation of the Grand Bay region using the QGIS software from satellite raster images, showing the demarked area with geospatial and attributes data. These were analysed using the area intersection in the QGIS Software. Vulnerability indexing was calculated using a risk matrix analysis which was in turn mapped in QGIS, showing highly exposed buildings, an account for human lives under major threat and areas that can suffer saline water infiltration as part of the negative environmental impact.