Seismic Observation and Analysis Based on Three-Component Fiber Optic Seismometer

Abstract

We demonstrate a three-component fiber optic seismometer for seismic observation, with no electronics in the sensor probe, but relying exclusively on optical fiber in the form of an unbalanced Michelson interferometer, with state-of-the-art performance characteristics. The fiber optic seismometer system is installed in the seismic observation cave at the Earthquake Administration Bureau of Jilin Province, in Changchun, Jilin, China, and has been operating without interruption for more than a year. Two minor earthquakes of different magnitudes recorded by the three-component fiber optic seismometer are analyzed and discussed in detail from the perspectives of time domain and frequency domain signal quality and fidelity. In addition, the recording results of the fiber optic seismometer are compared with those of the traditional electrical-mechanical seismometer co-located at the observation site. Actual observational results of the seismic events show that the three-component fiber optic seismometer can record the seismic waves clearly, with comparable performance as the conventional seismometer.

Keywords

• Optical fiber applications
• optical interferometry
• seismic measurements
• vibration measurement