Review of Seismic Characteristics in Erbil City, the Capital of the Kurdistan Region of Iraq

Abstract

Erbil city essentially suffers from the risk of earthquakes generated by Zagros-Taurus Belt. The central objective of this study is to identify the seismic characteristics and required seismic parameters for structural analysis. The methodology concentrated on reviewing the seismology and geology of Erbil city. It was concluded that the tectonically classified by an outer platform of the low folded zone in the position of Western Zagros Fold-Thrust Belt of the Arabian plate, geologically covered by Quaternary sediments and lithologically described by fluvial sediments, and the dynamic soil properties classified by site Class D. Seismicity review indicated that the seismic source is characterized by strike-slip (normal) fault and majority events exhibit at the shallow crustal with expected moment magnitude between 6 and 7.5. It was observed that the peak ground acceleration (PGA) has been updated, especially after the last cyclic earthquake in the region. The summary of the previous seismic hazard indicates that the PGA according to the World Health Organization, Global Seismic Hazard Assessment Program, and Uniform building code is identified by the value higher than 0.3 g for 475 years return period, while according to national probabilistic seismic hazard analysis studies in Iraq and Arabian Peninsula is identified by 0.4 g for 2% probability of exceedance in 50 years (2475 years return period), and estimated PGA to be 0.25 g for 10% likelihood of exceedance in 50 years (475 years return period), in a term of 5% damped at bedrock condition. Proposed spectral acceleration (Sa) in Erbil city at 0.2 and 1.0 s evaluated to be 1.0 g and 0.53 g, for the site Class D and compared with Sa in the literature.