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This study aims to present a technique that combines multi-sensor spatial data to monitor wetland areas after a flash-flood event in a Saharan arid region. To extract the most efficient information, seven satellite images (radar and optical) taken before and after the event were used. To achieve the objectives, this study used Sentinel-1 data to discriminate water body and soil roughness, and optical data to monitor the soil moisture after the event. The proposed method combines two approaches: one based on spectral processing, and the other based on categorical processing. The first step was to extract four spectral indices and utilize change vector analysis on multispectral diachronic images from three MSI Sentinel-2 images and two Landsat-8 OLI images acquired before and after the event. The second step was performed using pattern classification techniques, namely, linear classifiers based on support vector machines (SVM) with Gaussian kernels. The results of these two approaches were fused to generate a collaborative wetland change map. The application of co-registration and supervised classification based on textural and intensity information from Radar Sentinel-1 images taken before and after the event completes this work. The results obtained demonstrate the importance of the complementarity of multi-sensor images and a multi-approach methodology to better monitor changes to a wetland area after a flash-flood disaster.

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The Late Miocene – Early Pliocene Siroua strato-volcano is made of particular hyperalkaline rocks. It lies between the High-Atlas and the Anti-Atlas, in a collisional zone related to the continental subduction of the African plate under the Moroccan Meseta. Our field observations and analyses of SPOT, Landsat-MSS, and DEM (digital elevation model) imagery have permitted mapping of faults, joints, and volcanic edifices. The elongate shape of volcanoes and linear clusters of adjacent edifices, together with their relationships with faults, show that magma ascent was favored by tectonic crustal scale open fractures, essentially tension fractures, tail-cracks, and open faults. These fractures, together with other nonvolcanic, narrow, NNE-striking troughs, provide valuable information on the regional deformation since the Late Miocene. The shortening–extension type strain, which is responsible for the open fractures, is situated near the Azdem transform, a zone of active faults striking NNE, parallel to the convergence trend. The transform links two segments of the "Accident Sud-Atlasique," which constitute the border between the Moroccan Meseta and the African plate. The magma seems to originate from the lithospheric mantle, but asthenospheric material had previously migrated upward along the Panafrican suture zone. This mixed magma finally was transferred to the surface as a result of the onset of the open fractures prior to fault motions. The Siroua volcanic activity results from the conjunction of (1) a Panafrican suture zone and (2) a zone of open fractures due to "strike-slip" strain near a local transform inside the area of collision.

The Taza-Guercif Basin is on the southern margin of the former Rifean Corridor, one of the major Miocene marine connections between the Atlantic Ocean and Mediterranean prior to the onset of the Messinian Salinity Crisis. As the first basin in the corridor to emerge during corridor closure, the basin is a key location for understanding this major marine event. To constrain the mechanisms for corridor closure, we contribute 499 zircon U-Pb crystallization ages and 98 zircon fission-track (ZFT) cooling ages from the stratigraphy of the Taza-Guercif Basin. The U-Pb age signature of the Taza-Guercif Basin is dominated by Pan-African (700-560 Ma) and West African craton (2200-1800 Ma) ages, and contains a significant abundance of Mesoproterozoic ages recently characterized in Mesozoic sediments from the Rif and Middle Atlas mountains. The ZFT ages record a significant Triassic-centered cooling population (275-150 Ma), well-defined Variscan (ca. 330 Ma) and post Pan-African (498 Ma) cooling peaks, and a scattering of Precambrian cooling ages. The cooling ages suggest a source in the Middle Atlas; this is consistent with the U-Pb crystallization ages. Furthermore, there is no discernable change in either the U-Pb or ZFT populations during basin emergence. Together, these observations suggest that the Middle Atlas mountains were a consistent source of sediment to the Taza-Guercif Basin and played a significant role in the closure of the Taza-Guercif Basin and possibly the Rifean Corridor.