s Yaghmaei-Sabegh - Department of Civil Engineering, University of Tabriz, P.O Box ۵۱۶۶۶-۱۶۴۷۱ Tabriz, IranCorresponding Author

The main objective of this paper is to present a wavelet-based procedure to characterize principle features of a special class of motions called pulse-like ground motions. Initially, continuouswavelet transform (CWT) which has been known as a powerful technique both in earthquake engineering and seismology field is applied easily in automated detecting of strong pulses of earthquakes. In this procedure, BiorSpline (bior1.3) basis from biorthogonal wavelet families is appliedfor extracting of the largest velocity pulses from normal-fault component of selected records. Theselected wavelet decomposition process aids quantification of the effect of extracted pulses onacceleration and displacement response spectra. The results on elastic spectra show that, these pulsescause a significant amplification in the region of pulse period which should be appropriatelyincorporated in design procedure of structures in near field area. The results also have been presented for inelastic response spectra with different ductility levels

Wavelet analysis; Pulse-like ground motions; Elastic and inelastic response spectra; Pulse effect