Tsunami damage to North Sentinel Island

This Envisat Advanced Synthetic Aperture Radar (ASAR) multitemporal composite image highlights coastal destruction - including damaged coral reefs - on North Sentinel Island, part of the Andaman Islands in the Bay of Bengal. Radar images measure surface roughness rather than reflected light. The colour in the image comes from combining two separate ASAR images acquired on different dates in order to highlight differences between them. The yellow (combining red and green) is matched to a 3 June 2004 acquisition while the blue is matched to a post-tsunami acquisition on 30 December 2004. North Sentinel Island is home to a small indigenous tribe that refuses contact with the outside world. They are reported to have survived the severe damage done to the island.