An EGF-based methodology for predicting compatible seismograms in the spectral domain using GA technique

Abstract

SUMMARY The main objective of this paper is to present a methodology for predicting spectrum compatible seismograms at sites where main shock is not recorded by other sites from which the main event has been observed using recorded aftershocks. The genetic algorithm and multitaper method are employed to minimize differences between the calculated synthetic seismogram and observed data. The multitaper spectrum approach being used permits the reduction of spectral leakage providing the possibility of matching the Fourier spectral amplitudes corresponding to synthetic and observed waveforms. The proposed technique is applied to the 2006 Silakhor earthquake (Mw= 6.1, Iran) as a case study. The six component waveforms (L, T and V) at two stations were simulated by minimizing errors between the synthetic response spectra, the Fourier spectral amplitudes and those of the observed. The results are shown to be in a good agreement with those of the observed data. The three components of waveforms at the other three stations were predicted incorporating the calculated parameters. The validity of the technique is proven through demonstrating good agreement of the response spectra and Fourier spectral amplitudes corresponding to the predicted and observed seismograms at other three stations. It is concluded that, the methodology is applicable for predicting realistic acceleration time histories to be used in seismic performance evaluation of existing structures in the region under study.