Development of a regional attenuation relationship for Alborz, Iran

New attenuation relationships for rock and soil in Alborz, have been developed in this study. When the quantity of usable groundmotion data is inadequate in the magnitude and distance ranges, development of an empirical prediction equation is deficient. Due to lack of data, the two wellknown simulation techniques, point source and finitefault models have been used to generate more than ten thousands of strong motions as input data. The stochastic finitefault modeling that can be used to predict regional groundmotion for large faults has been developed based on subdividing the fault surface into smaller subsources, as stochastic point sources. The model incorporates the seismological information obtained from recorded data of northern Iran to provide new information on source and path effects. In this study, the uncertainty due to inherent variability in earthquake source, path, and site effects has been considered. The results include the attenuation relationships that are validated by statistical analysis to compare the estimated ground motion with those of recorded data at the observed stations in Alborz region.