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Abstract:
Mount Etna (Sicilia, Italy) is one of the most active volcanoes worldwide, located at the boundary between the African and the Eurasian plates. It is characterized by the occurrence of many phenomena such as lava flows, ash eruptions, earthquakes. Its eastern flank is also characterized by a complex system of active faults, associated with an eastward flank movement, up until the submarine environment. As Etna flanks are densely inhabited areas, we aim at better understanding the link between these phenomena to better assess associated hazards and risks. Since 2018, we have been measuring several locations with Distributed Fiber Optic Sensing yearly, enabling us to observe strain at meter-scale spatial interval and on a broad frequency range. We show records and present results from selected cables. Close to the summit active craters, we interrogate dedicated cables, and could analyze the ground response in association with explosions and volcanic tremor. In urban areas, we interrogate telecommunication cables and record local earthquakes. In the submarine area, we interrogate a cable which crosses the North Alfeo fault with several different optical techniques. In the southern flank of the volcano, we show volcanic signals from a cable deployed in a borehole. We also demonstrate how simultaneous multi-fiber measurements can help constrain earthquake hypocenter location. We discuss opportunities and challenges of using fiber optic cable in various environments such as the Etna volcano and beyond, for an integrated vision from deep processes, their interaction with the sub-surface dynamics and the volcano-tectonic structures.
