Complementarity of Optical Remote Sensing and Geographic Information System for Detection and Mapping of Geological Lineaments: A Case Study in the Metlaoui Region in Southern Tunisia

This study focuses on the region of Metlaoui (Southern Tunisia) where the marks of a neotectonic activity are spectacular. The main objectives are the detection and the mapping of the network of fractures at this region. Different techniques of automatic extraction of lineaments based on remote sensing images acquired from Landsat-7 ETM and Aster satellites were applied. The results obtained from this satellite-based approach were compared with the results from two independent approaches based on the interpretation of aerial photographs and the exploitation of topographic maps. Major lineament groups were described based on the shapes, orientation and lengths. The most prevalent groups are those oriented along the following axes: NE-S; NW-SE; NNE-SSW; E-W; and N-S. The most common are the lineaments oriented following NW-SE and E-W directions, which reflect the passage of the wellknown directional fault of Metlaoui. Combining information from satellite images, aerial photographs, topographic and geologic maps, accompanied with in-depth validation from field campaigns allowed the accurate detection of the tectonic accidents at high spatial resolution over the whole studied region. A new map of lineaments has been established. Its use to update the geological map of the Metlaoui region is in progress.