Ground vibrations detection with fiber optic sensor

In this paper, a fiber optic sensor based on fiber Bragg grating (FBG) is employed to measure the ground vibrations which may be generated by earthquakes, debris flows, landslides, and rock impacts on the ground. The detected vibration signals were analyzed by both fast Fourier transform (FFT) and Gabor transform to obtain the frequency response. The performance of fiber optic sensor was examined and compared with the conventional ground vibration geophone sensor. From the results of field tests, the fiber optic sensor shows highly similarity with conventional geophone sensor for low frequency measurement. The fiber optic vibration sensing system presented in this research is appropriate for sensing ground vibration in the frequency ranges of 10–250 Hz. The sensor proved to be an alternative option for ground vibrations monitoring system.