Iran Accelerograph Data Contraction Using Wavelet Analysis

The main purpose of this paper is to find an approximation of Iran strong motion records by a relatively small number of pulses (i.e. wavelets in an orthogonal wavelet family) considering wavelet importance in introducing the nature of ground strong motion. The Coiflet 5 wavelet family is used, which is orthogonal, smooth and nearly symmetric. Such representation is obtained by the expansion of velocity in orthogonal wavelet series using the Fast Wavelet Transform, and approximation by only the largest energy terms in the series. The goodness of the approximation is examined. The efficiency of the procedure is assessed by comparison some seismic indices such as input seismic energy, peak power and nonlinear oscillator collapse time which are achieved from the main and contracted signals.