Calculation of long-period response spectra to earthquake ground motion from seismograms of Type 513 seismographs

We introduce in this paper a method to calculate response spectra of earthquake ground motion from seismograms of Type 513 seismograph. The seismograms of two horizontal components of the M ^sub s^ 7.1 earthquake, an aftershock of 1976 M ^sub s^=7.8 Tangshan earthquake, recorded by type 513 seismograph in Taian station are used as an example. After curve digitization, arc shape curve correction, equal-distance interpolation and instrument response correction, the absolute acceleration response spectra, relative velocity response spectra and relative displacement response spectra of different damping ratios in the period range of T ≤ 10 s are calculated in frequency domain.[PUBLICATION ABSTRACT]