Fiber-optic Sagnac interferometer as seismograph for investigation rotation seismic events

In this paper we conclude application of the fiber-optic Sagnac interferometer as a rotational seismograph with rotation sensitivity equal to 4.3·10^-8 rad/s (for 2 ¿) for direct measurement of ground rotation component in near-field seismic events. The presented system based on the fiber gyro construction with optimization for measurement rotation speed instead angular changes. The experimental data obtained during research of the rotational components in the near-field seismic events allows to identify the amplitudes of such events in the range of 1.5·10^-6 rad/s to 2·10^-7 rad/s as well as time delay between them and classical seismic waves.