A fiber-optic gyroscope for rotational seismic ground motion monitoring of the Campi Flegrei volcanic area

• Marialuisa Capezzuto, guido gaudiosi, Lucia Nardone, ezio dalema, Davide DAmbrosio, roberto manzo, Antonio Giorgini, Pietro Malara, Paolo De Natale, Gianluca Gagliardi, Luigi Santamaria Amato, Danilo Galluzzo, and Saverio Avino
• received 01/17/2024; accepted 04/16/2024; posted 04/17/2024; Doc. ID 518354
• Abstract: The real-time monitoring of densely populated areas with high seismic and volcanicrisk is of crucial importance for the safety of people and infrastructures. When an earthquakeoccurs, the Earth surface experiences both translational and rotational motions. The latter areusually not monitored, but their measurement and characterization is essential for a fulldescription of the ground motion. Here we present preliminary observational data of a highsensitivity rotational sensor based on a 2-km long fiber-optic Sagnac gyroscope, presentlyunder construction in the middle of the Campi Flegrei Volcanic Area (Pozzuoli, Italy). We haveevaluated its performances by analyzing data continuously recorded during an acquisitioncampaign of five months. The experimental setup was composed by a digital nine-componentseismic station equipped with both the rotational sensor and conventional seismic sensors(seismometers, accelerometers and tiltmeters). During this experiment we detected seismicnoise and ground rotations wavefield induced by small – medium local earthquakes (MD < 3).The prototype gyroscope shows a very promising sensitivity in the range of 5 × 10―7 ―8 ×10―9𝑟𝑎𝑑 𝑠 𝐻𝑧over the frequency bandwidth 5 mHz – 50 Hz. Future upgrades andperspectives are discussed.