Development of PGA Attenuation Relationships for Iran

Structural dynamic analyses need different earthquake parameters such as design base acceleration, design spectra and earthquake records. In order to obtain base acceleration and design spectra of a site, prevailing method is based on seismic hazard analyses. In this method, base acceleration and design spectra are obtained from seismicity of the region, site condition based on probable statistical methods. One of the obligations in this method is having attenuation relations for different parameter such as PGA. In this research we update and make improvements of the PGA attenuation relationship, presented by Ghodrati et al. (2007) for site rock and soil bed conditions of the seismo-active states of Zagroz and, Alborz and central Iran. A total of 858 strong-motion accelerograms recorded for Alborz and central Iran and Zagros are used to obtain attenuation relation, which 477 records due to Alborz and central Iran. Regression analysis has been done for maximum of horizontal components and PGA attenuation relation coefficients are obtained.