How to detect rockfall events by optical fiber acoustic sensors

What is it about?

Rockfalls represent a major source of hazard in mountain areas, being the cause of rapid landslides. Fortunately, it is possible to predict collapses by detecting the acoustic emissions generated from internal cracks in rocks. In this work, we propose two different sensors for detecting the precursory acoustic emissions in rockfall events. Both sensors are based on interferometric schemes, with the first one consisting of a fiber coil used as a sensing element and the second one exploiting a micro-machined cantilever carved on the top of the ferrule.

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Photo by Fleur on Unsplash

Photo by Fleur on Unsplash

Why is it important?

The application of traditional AE sensors, such as accelerometers and piezoelectric transducers, finds serious practical limitations due to the faintness of these AEs and the hostility of typical mountain environment (with severe temperature, frequent lightning and ice storms, heavy rains and arduous access). With this respect, FOSs may fill the gap, providing a reliable solution and potentially offering the following features: more robustness to electromagnetic interference, smaller form factor, multiplexing capability, longer distance range (which leads to the easiness of installation), higher sensitivity.

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