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The quality factor of coda ( Q c) waves has been estimated by using single backscattering and single isotropic scattering models. The earthquakes used were recorded by three permanent and one temporary network located in the central and eastern Alborz, Iran. The database was composed of 746 local earthquakes with local magnitude from 1.1 to 5.7. The estimated Q c has been found to be similar for lapse times greater than twice the S ‐wave travel time (2 t S ) for both methods. The estimated Q c for central frequencies

We present a ground‐motion prediction equation (GMPE) for Turkey and Iran to investigate the possible regional effects on ground‐motion amplitudes in shallow active crustal earthquakes. The proposed GMPE is developed from a subset of the recently compiled strong‐motion database of the Earthquake Model of the Middle East Region project (see [Data and Resources][1]). A total of 670 Turkish and 528 Iranian accelerograms with depths down to 35 km are used to estimate peak ground acceleration, peak ground velocity, and 5% damped elastic pseudospectral acceleration ordinates of 0.01 s≤ T ≤4 s. The moment magnitude range of the model is 4≤ M w≤8, and the maximum Joyner–Boore distance is R JB=200 km. The functional form considers three major fault mechanisms (strike slip, normal, and reverse). The nonlinear soil behavior is a function of V S 30 (average shear‐wave velocity in the upper 30 m of soil profile). Our observations from empirical and estimated ground‐motion trends advocate regional differences in the territories covered by Iran and Turkey that originate from the differences in Q factors, kappa, and near‐surface velocity profiles. These factors eventually affect the magnitude‐ and distance‐dependent scaling of spectral amplitudes in Iran and Turkey. In essence, the ground‐motion amplitudes of these two neighboring countries would draw patterns different than the ground‐motion estimates of GMPEs developed from the strong‐motion databases of shallow active crustal earthquakes from multiple countries. Online Material: MATLAB code and regression coefficients for computing the response spectrum and distance scaling. [1]: #sec-7

Predictive attenuation relationships have been developed for peak ground acceleration and spectral coordinates based on observed and simulated records for East Central Iran. First, the predictive relationships are derived based on observed records. The observed data set, which was considered, includes a total of 258 records from 109 earthquakes with a magnitude range of 5.0–7.4 on rock site. Then a suite of ground motions has been simulated for a range of magnitude and distances based on the stochastic finite fault ground‐motion model. The theoretical–empirical attenuation relationship, which has been developed for the horizontal component of peak ground acceleration and spectral acceleration, is applicable to earthquakes of M w 5.0–7.4 at a distance up to 100 km. Online Material Earthquake catalog.