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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.

The peninsula of Tangier (Northern Morocco) is submitted to a significant number of landslides each year due to its lithological, structural and morphological complexity; which cause a lot of damage to the road network and other related infrastructure. The main objective of this study is to create a landslide indexed susceptibility map of Tangier peninsula, by using AHP (Analytical Hierarchical Processes) model to calculate each factor’s weight. The work is made via GIS by using an ArcGIS AHP extension. In the current research, First of all, the four main types of landslides were identified and mapped from existing documents, works and new data which came from either remote sensing or fieldwork. Lithology, land use, slope, hypsometry, exposure, fault density and drainage network density were used as main parameters controlling the occurrence of the selected landslides. Then, afterward, each parameter is classified into a number of significant classes based on their relative influence on gravitational movement genesis. The validity of the susceptibility zoning map which is obtained through linear summation of indexed maps was tested and cross-checked by inventoried and studied landslides. The obtained landslide susceptibility map constitutes a powerful decision-making tool in land-use planning, i.e. New highways, secondary highways, railways, etc. within the national development program in the Northern provinces. It is a necessary step for the landslides hazard assessment in the Tangier peninsula in northern Morocco.

Slide lands (Lands mass movements) are among the natural risks that Morocco faces in the Rifaines regions in particular. They generally constitute small-scale, punctual phenomena. But their diversity and frequency are nevertheless responsible for significant and costly damages and injuries. To deal with this problem, the study of field instabilities must take into account that: ithe ground movements must be taken in a context of the overall dynamics of the watershed, ii-the choice of more objective methods, which is not based on the very subjective opinion of the expert; iii-the choice of an adapted approach to the scale of work. In this article, we used the evidence theory "WofE" to evaluate the sensibility of landslide in the El Quola area. This method is based on the analysis of the relationships between landslides that occurred in the past (the so-called modelable variable Vm) and the spatial distribution of some predictive parameters of instability (Vp). The result obtained is a landslide susceptibility map that is the result of multi-disciplinary and multi-temporal data. This method has been described as one of the most performing by several authors; however, it requires a conditional independence between the different predictive factors. The quality of the performances was evaluated with success curves.