Comparison of methods for estimating fracture size and intensity applied to Aiguille Marbrée (Mont Blanc)

This article presents a multidisciplinary research devoted to correlate estimation of the rock mass characteristics with parameters and features obtained by the use of digital photography. The data obtained from remote slope analysis are then undertaken to a statistical analysis of discrete data samples comparing different survey areas in terms of shape and dimension of the sampling window. The method is developed by an application to the North rock face of the Aiguilles Marbrées (Mont Blanc). This slope was chosen as case of study since it represents an important high mountain location from the environmental and touristic point of view, where the severe working condition led to the application of innovative methodology. This site is monitored by a local authority (Fondazione Montagna Sicura) devoted to the territory safe control since a rock fall of considerable size occurred in September 2007. After a photogrammetric survey, an orthophotograph has been created; circular windows have been materialized on the orthophotograph to perform area sampling. Statistical analysis of the obtained data enables us to calculate parameters and estimators for rock mass classification.