Researchers have developed a prototype fiber optic gyroscope for detecting ground rotations caused by seismic activity in the volcanic area of Campi Flegrei in Naples, Italy. The goal is to improve risk assessment and potentially enhance early warning systems for earthquakes in this highly populated region. The gyroscope is based on the Sagnac effect, which measures the interference patterns of light traveling in opposite directions around a closed loop to detect angular velocity with high resolution.
The team, led by Saverio Avino from CNR-INO, published their findings in Applied Optics, sharing preliminary observational data from the rotational sensor. The 2-km long fiber-optic gyroscope was tested over five months and was able to detect noise and ground rotations from small to medium earthquakes in real time. This information adds to the existing grid of multiparametric sensors in Naples, providing a more comprehensive understanding of seismic and volcanic activity in the region.
By capturing ground rotations, researchers hope to gain insight into the Earth’s internal dynamics and seismic sources during volcanic activity. Gyroscopes are typically used to measure changes in orientation or angular velocity, and the developed sensor aims to detect rotational movement in seismic waves. With further development, the team plans to set up a three-axis gyroscope to capture all components of the rotation movement in the Campi Flegrei area.
The fiber-optic rotational sensor was created using standard laboratory equipment and components, with a 2-km long optical fiber cable forming a loop connected to an aluminum spool. This system showed comparable resolution to other state-of-the-art gyroscopes and had a good duty cycle, allowing continuous data acquisition for several months. The controlled laboratory environment sits on top of a volcano caldera, providing a natural source of earthquakes for measurement and analysis.
Danilo Galuzzo from INGV emphasizes the importance of measuring ground rotations as part of the mosaic of sensors monitoring volcanic earthquake signals. The data collected from the prototype gyroscope has the potential to aid in detecting changes in volcano dynamics and seismic phenomena in the Campi Flegrei region. The ultimate goal is to establish a permanent ground rotation observatory that could contribute to improved understanding and monitoring of seismic and volcanic activity in the area.
By combining multiple gyroscopes oriented to capture different axes of rotation, researchers aim to create a comprehensive three-axis gyroscope for advanced monitoring of ground rotations. Understanding the rotational movements during seismic and volcanic events could provide valuable insights for improving risk assessment and early warning systems in the metropolitan city of Naples, where millions of people live near active volcanic areas. With ongoing research and development, the team hopes to enhance the resolution and stability of the gyroscope for long-term monitoring in the Campi Flegrei region.