Susceptibility to Mass Movements in the Metropolitan Region of Natal, Rio Grande Do Norte, Brazil

Intense urbanization is a phenomenon present in several Brazilian cities. If done in an uncontrolled and inadequately studied manner, it can cause significant negative impacts, among them landslides, which are felt more intensely by populations located in high-risk areas. To avoid or mitigate these impacts, environmental geotechnics can contribute by providing the necessary tools to assess the susceptibility of a certain region to landslide. In this sense, the objective of this study was to evaluate the possibility of landslide in the metropolitan region of Natal, Rio Grande do Norte, Brazil, by calculating the factor of safety (FS) using the QGis software. To analyze susceptibility, according to NBR (Brazilian Norm) 11.682, it was considered that regions with an FS less than 1.5 can be considered risky, with values of 1.30 and 1.15 suitable for regions with medium and low degrees of necessary safety. For this, an assessment of the acting and resisting forces was made, requiring the use of another study already conducted in the region that provided the soil parameters used in the calculations. Additionally, two methods were considered for calculating the thickness of the soil—the S and Z methods, which differ in the parameters used for this purpose. At the end of the study, it was estimated that this region has few points of concern. This may be due to the type of soil predominant in the area and the fact that the city is mostly flat. Furthermore, it was confirmed that most of the regions with a lower factor of safety are located under environmental protection, and therefore, construction is not allowed in their surroundings. However, some exceptions were observed, including a specific location with a factor of safety value of 1.02. Although this location is in an environmental protection zone, its landslide can present risks since it is located near an inhabited area.