Monitoring and characterization of surface movements in rock slopes

Surface movements in rock slopes may evolve at widely different rates (from millimeters per year to meters per second) and be the expression of widely different instability mechanisms (from detachment and fall of individual rock blocks to deep-seated gravitational slope deformations). The past two decades have seen a significant push in the development of remote sensing, close-range, and conventional geotechnical techniques to better deal with this variability and enhance the assessment of related slope hazards. As a result, comprehensive monitoring and characterization of rock slope movements may now be achieved even in complex scenarios and at fine scales, provided that the appropriate techniques are used. Building on the experience acquired by the engineering geology research group at the University of Florence (Italy), this paper briefly highlights a series of case studies—including kinematic analysis of potential rock slope movements as well as detection of ongoing “slow” and “very rapid” rock slope movements—which illustrate how important insights may be gained with different techniques according with the site-specific characteristics of the investigated hazard. It is shown that a more holistic view can generally be obtained using a combined approach, overcoming the limitations inherent to each single technique. Future developments should primarily concern optimizing the interoperability and compatibility between the large sets of output data, which would ultimately facilitate their manipulation from end-users and the derivation of informed decision-making.