Evolutionary Spectra of Seismogram by Multifilter

Abstract

The multifilter technique is applied to calculation of the evolutionary power spectra of strong motion seismograms. Formulation of the evolutionary power spectrum is made in terms of the total energy of the filter output, the result of which is applied to accelerograms recorded in the United States and Japan. On the basis of numerical results, the acceptable range of the filter damping factor is found to be 0.05 - 0.2. It is shown that simulated accelerograms based on the evolutionary power spectra obtained in this study maintain quite well the nonstationarity of the original accelerograms both in intensity and spectral characteristics.