Landslide risk assessment using digital photogrammetry and Gis multi criteria evaluation IN Matmata region (SE Tunisia)

Identifying the prone sites and recognizing the influencing factors of rock failure remains a major challenge, especially for the regions lacking a historical database of the chronological evolution of the different potential factors influencing the frequency and the amplitude of this hazard in the mountain zones. In this context, the present study aims to delineate the movement of the rocky masses after the frequent torrential rainfall and to assess the main driving factors of the landslide hazards in the Matmata region (SE Tunisia). The used approach relies on field observations, remotely sensed data, digital photogrammetry, and GIS-multi criteria assessment. The analysis of the kinematics of the rock cliffs triggering in the region between 2016 and 2023 highlights a relative movement of about 39 m of the carbonate rock masses related to the impacts of geological factors, weathering, land use changes, hydrogeology, and human activities on slope stability and rockfall occurrences. The hierarchical influence of these factors illustrates relevant spatio-temporal variability of susceptibility indices. The southern part of the region is characterized by the highest degree of vulnerability due to many factors such as slope, rainfall and lithology. The spatial distribution of the final susceptibility index indicates varying degrees of susceptibility across the study area amplified during the last years given the frequency of the extreme events. The susceptibility map is validated by landslide inventory. The findings highlight the relevance of the rockfall hazard and the relative amplitude in the region explained by a high index of urban expansion and infrastructure development in hilly areas. The obtained results present a valuable tool for decision-making for land use management and landslide mitigation measures.