Mapping lineaments using Landsat 8 OLI and SRTM data; a case study of the eastern part of the Ouarzazate Basin, Morocco

The integration of remote sensing and geographic information system (GIS) was employed in this study to delineate the structural lineaments within the eastern section of the Ouarzazate Basin, situated between the southern front of the Central High Atlas and the northern slopes of the Eastern Anti-Atlas (also known as the Saghro Massif). To achieve this objective, Landsat 8 Operational Land Imager (OLI) and Shuttle Radar Topography Mission (SRTM) data were used. Principal Component Analysis (PCA) was computed and a directional filter was applied to the first PCA and the panchromatic band (B8). Additionally, shading was applied to the SRTM data in four directions; N0°, N45°, N90°, N135°. After removing of the non-geological linear structures, the results obtained, using the automatic extraction method, allowed us to produce a synthetic map that included 1251 lineaments with an average length of 1331 m and was dominated by NE-SW, ENE-WSW and E-W directions, respectively. However, the high lineament density is clearly noted in the Anti-Atlas (Saghro Massif) and at the level of the northern part, extending from the Ait Ibrirne to Arg-Ali Oubourk villages. High lineament density can always be found around the major faults affecting this area. The data collected during the field investigations and from geological maps show that the major direction of the faults and structural accidents range mostly between N45°, N70° and N75°. The correlation of remote sensing results with those collected in the field shows a similarity and coincidence with each other. From these results, it is possible to consider the automatic extraction method as a supplementary kind that can serve classical geology by quickly enriching it with additional data. As shown in this work, this method provides more information when applied in arid areas where the fields are well outcropped.