Analysis of fiber optic sensor application to precursory acoustic signals detection in rockfall events

Two fiber optic sensors (FOSs) for detection of precursory acoustic emissions in rockfall events are proposed and experimentally characterized. While both sensors are interferometric, the first one use a fiber coil as sensing element, whereas the second sensor exploits a micro-machined cantilever carved on the top of a ferrule. Preliminary experimental comparison with standard piezo-electric transducers shows the viability of such FOSs for acoustic emission monitoring in rock masses.