Satellite observations of coastline changes in the Andaman islands after the 2004 Sumatra earthquake

Abstract

Following the M9.0 Sumatra earthquake on December 26, 2004, elevation and subsidence on separate parts of the coastline of the Andaman Islands have been reported. In this study, we use satellite imagery to map the coastline changes due to land elevation or subsidence after the earthquake in the Andaman Islands. The NIR band of SPOT-5 images before and after the earthquake was used to delineate coastlines. Images with similar tide levels were chosen for comparison. Elevation or subsidence is indicated by the emergence or submersion of corals and mud flats in the pre- and post-earthquake images. Our results indicate a general tilt of the main Andaman Islands in a direction in agreement with seismological estimates of the thrust-faulting between the Burma and Indian plates. Changes in coastal bathymetry were estimated using a shallow water reflectance model. The vertical displacement is estimated to be about 1 m for the uplifted areas on the northwestern coast. © 2005 IEEE.