Monitoring test of crack opening in volcanic tuff (Coroglio Cliff, Italy) using distributed optical fiber sensor

We report the experimental application of distributed optical fiber sensors based on stimulated Brillouin scattering (SBS) through the so-called Brillouin Optical Time Domain Analysis (BOTDA) to the monitoring of artificially induced crack opening in a volcanic rock slope. The aim of this chapter is to show how the sensing optical fiber cable is able to detect the formation and to follow the growth of fractures in the tuff rocks and to identify their location along the cliff. The experiments have been performed at the base of the Coroglio tuff cliff in Naples (Italy) and have demonstrated that early detection of crack opening can be obtained and development of early warning systems is an attainable goal of the research.