Geological applications of Landsat Enhanced Thematic Mapper (ETM) data and Geographic Information System (GIS): mapping and structural interpretation in south-west Iran, Zagros Structural Belt

Arabia-Eurasia convergence is achieved in north-west Zagros by a combination of shortening on NW-SE-trending folds and thrusts, mainly in the Zagros Structural Belt, and by right-lateral strike-slip on the NW-SE-trending Main Recent Fault. Structural patterns are often used as indicators of major features on the surface. In the present study, Landsat Enhanced Thematic Mapper (ETM) data from 9 November 2002 was digitally processed to enhance the structural patterns. The contrast stretching of ETM band 4 was found to be the best in displaying lineaments and folds for the area, hence was further processed by using directional filters and generating different combinations of false colour composites (FCCs). Finally, a structural map of the study area (Dezful-Brojerd) was prepared using the processed ETM images. This study indicates that the Landsat ETM data are useful for locating and interpretation of the structural features in the Zagros Structural Belt. Examination of the Landsat ETM 2002 images combined with field visits revealed that the area is highly active and structurally is in a dynamic state due to compressional forces. However the density of the structural features on the imagery calibrated to several field visit data shows that the south and south-east of the study area are not as tectonically active. This may be clue to presence of thick evaporite sequence of Gachsaran Formation on the Landsat image.