Landslide: A recurrent phenomenon? Landslide hazard assessment in mountainous areas of central Greece

In mountainous areas, the impact of landslides can be highly extensive and their occurrence can cause loss of life, destruction of infrastructure, damage to land, and loss of natural resources. The present work focuses on studying the recurrence of landslides and the production of landslide hazard assessment map. A mountainous part of central Greece has been selected as the case study, where landslide events comprise a common phenomenon. Initially, a landslide inventory map was created, and the recurrence of the landslide was identified. The Analytical Hierarchy Process (AHP) supported by a Geographical Information System (GIS) was utilized to correlate the ten selected instability factors and to produce a landslide hazard assessment map. The generated map was analyzed to assess the impact of uncertainties, and it was validated using frequency ratio statistical analysis. The outcome revealed 106 landslide events that occurred in the study area. The recurrent landslide was recorded in Ropoto village, which destroyed the central part of the settlement. The results of the applied method proved that the areas of very high and high landslide hazards are located mostly in the western, south-western, and southern parts of the study area. The insignificant variations of the spatial distribution of the landslide hazard zones showed a robust behavior for the model predictions. The satisfactory agreement between the landslide hazard zones and the distribution of landslides events demonstrated reliable predictability of the applied method. Finally, 70% of the existing urban fabric boundaries and the current road network are located within the limits of high and very high landslide hazard zones. The proposed procedure may be utilized for land use planning projects, implementation of the appropriate hazard mitigation techniques, as well as in emergency preparedness planning.