Landslides are one of the natural hazards that many countries around the world are facing. In Morocco, the Rif regions are the most affected by these phenomena. Each year they cause enormous damage to the road network and infrastructure, especially in our study region, the province of Larache.The study region is subject to several opening up and road construction projects, which is why it is necessary to predict and identify the most vulnerable areas beforehand, in order to propose measures and techniques which are adequate for protection and reinforcement.The main goal of this study is to develop a susceptibility map to ground movements using a multi-criteria spatial assessment approach, and in order to reduce subjectivity, we have used a method for analyzing such complex decisions, which is the analytic hierarchy process (AHP) implemented in the geographic information system (GIS). Seven factors have been considered as conditioning factors in the occurrence of landslides, which are: lithology, fracturing density, slope, aspect, land use, density of the hydrographic network, and altitude. To verify the results obtained, we performed a correlation analysis of ground movements, already inventoried and verified in the field, with the susceptibility classes that were calculated. This analysis is accompanied by a statistical study.

Abstract.As part of the geotechnical studies of a road project, a geophysical investigation by electrical tomography, microgravimetry, and boreholes, was carried out in order to locate if the areas can present or not a risks of ground instability along the survey had demonstrated that the area may present major risks for the stability of the road platform. related to the existence of large expanses of saliferous rocks underground voids under the future road. The results of this geophysical survey have allowed the designer office to propose more suitable solutions to solve this problem or even the possibility of shifting another site.

The Tleta of Beni Ider region located in the SW of Tetouan (Rif Septentrional) knows many mass instabilities. The diagnostic via the inventory, the mapping and the characterization of mass movements was made by using satellite imagery, aerial photography and field data coupled with existing documents (geological, geomorphological,…). The understanding of both their spatial distribution and the mechanism generating them, is very complex because of the existence of an important number of natural factors (geological, geomorphological, hydrological) in a relative mountainous landscape with deep valleys, steep slopes and significant elevation changes. Thus, a multidisciplinary approach was adopted to elaborate the landslide susceptibility map of the region taking into account interactions and causal relationships between the various natural parameters that tend to accentuate and aggravate the setting of landslides. The multidisciplinary database allowed us to evaluate the susceptibility thanks to a bivariate probabiliste model (Weight of Evidence). The obtained landslide susceptibility map is a major contribution to the development of urban development plans in the region.

As part of the geotechnical studies of a road project, a geophysical investigation by electrical tomography, microgravimetry, and boreholes, was carried out in order to locate if the areas can present or not a risks of ground instability along the road alignment. The road is located near a rock salt mine. This geophysical survey had demonstrated that the area may present major risks for the stability of the road platform. This risk is related to the existence of large expanses of saliferous rocks.The dissolution and exploitation of salt provoked underground voids under the future road. The results of this geophysical survey have allowed the designer office to propose more suitable solutions to solve this problem or even the possibility of shifting another site.

Relative movements of microplates developed between the African and Eurasian plate characterize the continuity of the tectonic movements in Westerner of the Mediterranean Sea. The convergence movements between these plates, at the origin of the current structuring in oriental Rif. The recent tectonics in the south ripple of Alboran Sea, translated by an important seismic activity, In the North of Morocco, exactly in the Al Hoceima region, considered as zone of plates border with important seismicity. The structural analysis made in this paper and the interpretation of focals mechanisms earthquakes characteristics in the Al Hoceima region, has allows to deduct the main directions of faults, which we compared with the results of the satellite images. This study we has provides to demonstrate the directions of faults which are able to generate earthquakes in the future. The direction NE-SW represents the overall faults dominant in oriental Rif, this major direction coincides with the breaks of surface. A reduced number of faults shows a generall direction NNE-SSO to N-S through the Quaternary formations in the NO of Al Hoceima city, the direction NO does not show a good correlation with the directions of surface rupture, as well as with the deducted directions from focals mechanisms. This study drives us to propose that faults of direction NNE-SSO to NE-SO, represent the major directions of the faults in the Al Hoceima region, which represents the main cause of the seismic activity in the region.