A new empirical ground-motion model for Iran

Abstract

In this study, we developed a new ground-motion model (GMM) for the 5% damped horizontal spectral accelerations using a newly developed database of strong-motion records for Iran. The newly developed GMM includes peak ground acceleration and 5% damped elastic pseudospectral acceleration ordinates of 0:01 s ≤ T ≤ 4:0 s. We used a database containing 1356 records from 208 events up to 2013, with the moment magnitude range of 4:8 ≤ M ≤ 7:5, and the rupture distances or closest distance to the rupture plane RRUP up to 400 km. The selected database includes a variety of fault mechanisms, for example, strike slip, normal, and reverse.We used Akaike and Bayesian information to determine the validity of the chosen regression model. We introduced random-effect coefficients in our mixed-effect regression model to capture the regional variations among Zagros, Alborz-Azarbaijan, Kope Dagh, and central east Iran and found no statistical variations among these regions. As part of the developed GMMs, we included the nonlinear site effect using VS30 (average shear-wave velocity in the upper 30 m of soil profile). Distribution of residuals obtained considering between-event, site-to-site, and event-station showed no discernable trends for the developed GMM. Furthermore, our proposed model is compared with Kale et al. (2015), which has been a recent and well-established new generation model for Iran and Turkey.

Publication Title

Bulletin of the Seismological Society of America

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