The kinematic behavior of slope failures in fractured rock masses is strongly influenced by the presence of discontinuities. Block size and shape are controlled by fracture orientation, intensity and length.

A preliminary analysis of these parameters was conducted in the north-eastern cliff of the San Leo plateau (Italy). Classical stereographic projection analysis, coupled with GIS, and a limit equilibrium approach were applied to analyze the blocks shape and the block kinematic constraint and thereby define the expected movement directions of selected rock wedges.

Our analyses provided further insights into the instability mechanisms involving the sub-vertical cliff faces. The data are also useful in the interpretation of the data collected by the slope monitoring system. By deriving the expected direction of movements, its effectiveness can be improved.

The size distribution and the shape of the blocks in the landslide deposit were mapped and classified, providing the constraint for more advanced geomechanical analyses.