Ground penetrating radar investigation of limestone cliff fracturing in the French Alps

Among many natural hazards, rock falls are a very frequent phenomenon in mountainous areas, characterized by its suddenness and its difficulty to predict. The growing urbanisation in these areas implies-to better assess this hazard, and consequently to determine the location and volume of a rock mass which could fall. The stability assessment of a rock mass is generally based on surface observations (slope morphology, structural properties of the massif, deformation measurements). Even if these studies are necessary, the lack of information within the rock mass and, particularly, on discontinuities (geometry, properties) leads to major problems in hazard assessment.