Geofizika, Vol. 13 No. 1, 1996.
Preliminary communication
Calibration of the Wiechert seismographs relative to a reference seismometer
Marijan Herak
Ivo Allegretti
Davorka Herak
Seweryn J. Duda
Abstract
The horizontal 1000 kg Wiechert seismograph has been calibrated on the basis of a comparison of its records to the ones that were obtained by the reference seismometer. The resulting magnification curve shows notable deviations from the theoretical one. Its most prominent feature is a sudden magnification increase observed for frequencies above 5 Hz, which is attributed to frame oscillations excited by the seismic waves. Also, the observed average response curve exhibits larger magnification for frequencies below the resonance frequency. The results indicate a non-linear behavior of the Wiechert instrument related to the degree of impulsiveness of the excitation.
Keywords
Seismograph calibration; historical instrumentation; Wiechert seismograph
Hrčak ID:
18775
URI
Publication date:
1.12.1996.
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