Home – Home – Jornals – Avtometriya 2003 number 5

New application areas of the fiber-optic interferometer in the Sagnac configuration are proposed and discussed. Because this system detects the absolute rotation in the plane of its sensor loop, the application is directly designed for detection of the rotational events. From the seismological point of view, such events are named seismic rotation waves. In most cases, the seismic rotation waves are extracted from recordings of differential seismic signals. Thus, all differences in responses of the seismometers cause disturbances that obscure these hidden components as it is for two antiparallel pendulum seismometers (TAPS) system. The presented fiber-optic rotational seismometer (FORS) is free from this disadvantage, and can be used for calibration of other rotational seismometers as well as for detection of seismic rotation waves. A design based on the well-known optical gyroscope configuration but with optimization for detection of only the pure rotation is presented. Its application for the TAPS system calibration is considered. The obtained results were the source of TAPS work improvement by applying the data smoothing by spline functions. Moreover, the first application of FORS has shown that probably the rotational parts exist in seismic events only for strong earthquakes.