Strain sensors based on Fiber Bragg Gratings for volcano monitoring

We present the experimental activity on the development of a Fiber Bragg Grating (FBG) strain sensor for volcano monitoring. We produced and tested a prototype of FBG strain sensor, with a high resolution and accuracy in static measurements and with a low-cost readout system. Here we present the results of a field campaign with a preliminary single-axis FBG strain sensor prototype on Mt. Etna, which was carried out in order to check the system performances in out-of-the-lab conditions and in the hostile volcanic environment (lack of mains electricity for power, strong diurnal temperature changes, strong wind, erosive ash, snow and ice during the winter time), and to determine whether measurable changes are induced across a 1989 fracture system during the paroxysmal phases of Etna's volcanic activity. In addition we present the design and laboratory test of a multi-axis strain sensor configuration.