عنوان مقاله [English]
This article intends to investigate the effects of site-to-fault distance on the earthquake intensity measure (basic design acceleration, A, and response spectra, Sa) where is not taken into account in Iran standard No. 2800. Regarding that the relation between site-to-fault distance and the design-base acceleration (A) parameter (or Sa) in currently used attenuation relations is highly non-linear, thus assigning the same value of such parameters to different site-distances in big cities, particularly at near fault sites, seems to be quite challengeable. In order to make this problem clear, forty series of site specific seismic hazard analysis in the two cities, Ahwaz and Kerman, are performed over ten sites having four different site-soil conditions and the “A” parameters are calculated and discussed. The results of this study showed that the site-to-fault distance can significantly influence upon the site’s intensity measure (A) parameter (about several times as distance become smaller) and have significant differences with those of the Standard No. 2800. This problem also highly affects the effectiveness of “N” parameter presented in thee 2800 standard as the representative of near fault directivity parameter.