Applicability of different ground-motion prediction models for northern Iran

A total of 163 free-field acceleration time histories recorded at epicentral distances of up to 200 km from 32 earthquakes with moment magnitudes ranging from M (w) 4.9 to 7.4 have been used to investigate the predictive capabilities of the local, regional, and next generation attenuation (NGA) ground-motion prediction equations and determine their applicability for northern Iran. Two different statistical approaches, namely the likelihood method (LH) of Scherbaum et al. (Bull Seismol Soc Am 94:341-348, 2004) and the average log-likelihood method (LLH) of Scherbaum et al. (Bull Seismol Soc Am 99:3234-3247, 2009), have been applied for evaluation of these models. The best-fitting models (considering both the LH and LLH results) over the entire frequency range of interest are those of Ghasemi et al. (Seismol 13:499-515, 2009a) and Soghrat et al. (Geophys J Int 188:645-679, 2012) among the local models, Abrahamson and Silva (Earthq Spectra 24:67-97, 2008) and Chiou and Youngs (Earthq Spectra 24:173-215, 2008) among the NGA models, and finally Akkar and Bommer (Seism Res Lett 81:195-206, 2010) among the regional models.