REVEALING THE GEOLOGY OF THE GREAT-NICOBAR ISLAND, INDIAN-OCEAN, BY THE INTERPRETATION OF AIRBORNE SYNTHETIC-APERTURE RADAR IMAGES

A number of new geological structures have been revealed in the Great Nicobar Island, Indian Ocean, from the analysis of airborne synthetic aperture radar (SAR) data. The advantages of SAR images for mapping ge ological structures over other images for the Great Nicobar Island, th e southern most island of Andaman-Nicobar are, have been highlighted. A visual analysis of lineaments in the southern part of the Great Nico bar Island using SAR and Landsat TM colour composites, TM bands 2, 3, and 4, and TM bands 4, 2 and SAR, reveals a wealth of structural infor mation not shown on previous maps. Other identified features include l ithological units derived from landforms, northwest-southeast trending faults, faults trending towards the mouth of Galathea river, the grab en valley, and many other new faults. The geological features reported in this work were verified using limited ground checking.