Correlation between natural slope angle and rock mass strength rating in the Betic Cordillera, Granada, Spain

This study proposes a method to determine zones gentler or steeper than the equilibrium slope angle based on rock mass strength (RMS) and to regionalize the parameters. The method was developed using GIS and applied to rock masses of the Alpujarride Complex (Granada, Spain). 41% of the natural slopes studied have angles lower than the equilibrium due to dissolution processes and the presence of alluvial or colluvial deposits, while 28% of those slopes have angles higher than the equilibrium due to rapid erosion in tectonically active zones. Cross correlation analysis between maps showing degrees of slope equilibrium and landslide inventories suggest that long-term geomorphic changes have induced slope angles higher than the equilibrium which are associated with rock falls and rock slides.