LITHOLOGIC AND STRUCTURAL MAPPING OF THE NORTHEAST LAKE ZIWAY AREA, ETHIOPIAN RIFT, WITH THE HELP OF LANDSAT TM DATA

Abstract

By integrating the interpretation of interactively enhanced Landsat
Thematic Mapper (TM) image with field data it was possible to map the lithology and structures of the area located in the central part of the Main Ethiopian Rift (MER). Most lithologic contacts, faults and lineaments that were not identified in previous geological and structural maps of the region are mapped with better accuracy, minimum cost and shorter field season. Different image enhancement techniques were applied to enhance the original data. The resultant image is
interpreted visually. The results of the work showed four major volcanic rock units, namely: 1. the lower series of pyroclastic deposit, 2. the basaltic series, 3. pyroclastic deposits of the rift floor and 4. recent lava flows. Three sets of faults were also mapped; 1. NE-SW striking rift-margin faults, 2. NW-SE to NNWSSE trending trans-rift faults and lineaments and 3. the youngest and active NNEssw to N-S faults of the Wonji Fault Belt (WFB).