A. Zarean - Ferdowsi University
H. Sadeghi - Ferdowsi University
E. Haghshenas - IIEES

Site amplification in the Khorasan Seismic Network, Iran, was estimated using small earthquake events (ML ۱.۶-۵.۵) recorded from ۲۰۰۳ to ۲۰۰۶. This seismic network consists of ۵ broad band stations (NJ, MH, BJ, QU and SB) distributed in Razavi and North Khorasan provinces. A total of ۲۵۵ three-component waveforms from ۸۸ events were used in this study. The wide dynamic range of the Guralp instrument provided a broadband seismogram for S-waves. Site effects were estimated by linear inversion using the reference site (NJ). The S-wave quality factor was found to be approximated by the relation ۱۶۵f ۰.۴۸ in the frequency range ۰.۶-۱۰Hz. It was found that the siteamplification factor for three kinds of geometrical spreading model R-۱, R-۰.۷۵, R-۰.۵ was similar but the quality factor varied.

Site Effect, Spectral Ratio, Inversion, Khorasan