Development of risk-targeted seismic hazard maps for the Iranian plateau

Abstract

This study aims to provide the risk-targeted seismic design maps and corresponding adjusting coefficients for different intensity measures on the Iranian plateau, using the iterative risk integral approach. The main purpose of this study is to provide the risk-targeted hazard maps with a uniform level of risk based on an acceptable collapse probability and risk threshold. The investigation applies the most recent and notable seismic hazard model for the studied region, namely the Earthquake Hazard Model of the Middle East (EMME). Having done the preprocessing procedures for characterizing the possible bias in the input data, hazard curves on 0.1° grids were extracted from the median values of the logic tree of the EMME model. Utilizing the deliberately rational values of the required parameters by the risk-targeting approach, i.e. 2% exceedance probability in 50 years as the 10% quantile of the fragility function, leads to reach some multiple uniform seismic risk maps with 1% probability of collapse in 50 years for each intensity measure. The imaginable inconsistency of the maps with historical data (as a picture of reality) has also been assessed in terms of underestimations or overestimations, using a two-sided statistical test at a 95% confidence level. The outcome of this study can be incorporated in the next revision of the national seismic code for a more reliable and robust seismic design of building structures.