Probabilistic seismic hazard assessments (PSHA) form the basis for calculating seismic loads in most contemporary seismic provisions in building codes around the world. The current building code of Iraq, which was published in 1997, is currently undergoing a significant engineering update. This study was undertaken in order to support the building code update and to satisfy the need in Iraq for a contemporary assessment of seismic hazard in terms of spectral accelerations. Seismic source characterization largely relies on a newly compiled earthquake catalog since sufficiently detailed information is not available on active faulting in the country even though there are numerous known active faults. There is also a lack of locally recorded strong-motion data. As a result, we make use of attenuation tomography studies in the region to compare local attenuation characteristics with that in other parts of the world where ground-motion prediction equations are available for use in PSHA. For most of the country, the attenuation of 1HzLg waves indicates an attenuation rate that is slower than active tectonic regions but faster than stable continental regions. Hence, we use ground-motion prediction equations from active tectonic and stable continental regions, weighted equally. The PSHA results are presented for a 2% chance of being exceeded in 50 years and on a reference ground condition of the National Earthquake Hazards Reduction Program (NEHRP) site class B. The probability level and reference ground conditions were selected to be consistent with the update of Iraq’s building code. The largest hazard, and consequently the design ground motions, is in the northern cities of Sulaymaniyah and Erbil, consistent with the fact that they are the two urban areas closest to major tectonic features to the north and east of Iraq. Additionally, the Badra–Amarah fault zone is a significant contributor to seismic hazard in the country; therefore, urban areas near it exhibit high seismic hazard.

中文翻译：

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伊拉克的概率地震灾害评估

概率地震危险性评估（PSHA）构成了计算世界各地建筑法规中大多数当代地震规定中地震荷载的基础。伊拉克的现行建筑法规于1997年发布，目前正在进行重大工程更新。进行这项研究是为了支持建筑规范的更新，并满足伊拉克在频谱加速度方面进行当代地震危害评估的需求。地震源的表征在很大程度上取决于新近编制的地震目录，因为即使有许多已知的活动断层，该国的活动断层也没有足够详细的信息。也缺少本地记录的强运动数据。结果是，我们利用该地区的衰减层析成像研究，将当地的衰减特征与世界其他地区的地面运动预测方程可用于PSHA进行比较。在该国大部分地区，1HzLg波的衰减表明其衰减速率比活跃的构造区域要慢，但比稳定的大陆区域要快。因此，我们使用来自活动构造和稳定大陆区域的地震动预测方程式，进行加权。提出PSHA结果的可能性是在50年内超过2％的机会，并且是在国家地震减灾计划（NEHRP）B类场地的参考地面条件下进行的。选择的概率水平和参考地面条件与更新伊拉克的建筑法规。最大的危害 因此，设计地面运动发生在北部城市苏莱曼尼亚和埃尔比勒，这与它们是伊拉克北部和东部最接近主要构造特征的两个城市地区这一事实相吻合。另外，巴德拉-阿马拉断层带是该国地震危险的重要原因。因此，它附近的城市地区具有很高的地震危险。