Geostructural and geognostic survey for a stability analysis of the calcareous cliff of Ispica (Hyblean plateau, southeastern Sicily)

The paper reports a geostructural and geognostic survey to evaluate the stability conditions of the highly fractured calcareous cliff where the Monastery of the “Frati Minori” of Ispica is located. A large number of fractures affect the whole cliff, resulting in dangerous conditions. In addition to a careful inspection of the slope to measure the structural discontinuities and identify rock blocks larger than 1 m3, cored boreholes were extended to a depth of 30 m. The rock quality designation indicated that the rock quality varies from poor to fairly good. In this steep, vegetated area, the use of different investigation methods was necessary to determine the physical, mechanical and geometric parameters necessary to plan the remedial works and measures to reduce the risk of rocks falling.