A strong earthquake occurred on November 12, 2017, in Sarpol-e Zahab city, western Iran, with the moment magnitude (\(M_{{\text{w}}}\)) of 7.3 and a focal depth of 18 km. The maximum horizontal peak ground acceleration of 0.69 g was recorded at the Sarpol-e Zahab station. Significant damages were observed in frame and masonry buildings, while the damage distribution was non-uniform throughout this small city. The preliminary site reconnaissance revealed that numerous engineering structures collapsed or considerably damaged in some regions, contrary with those non-structural masonry buildings in other regions which remained intact during earthquake. This paper represents a preliminary reconnaissance report prepared through the site visit done by the authors, a few days following the earthquake occurrence. Then, the data recorded by the strong ground motion stations in the affected city and the surrounding regions together with the geotechnical data gathered from the available boreholes in Sarpol-e Zahab are incorporated for probabilistic seismic hazard and local site effect analyses. The observed response spectra at two stations and distance-dependency of ground acceleration are compared with those predicted by some attenuation models. The results of probabilistic seismic hazard analysis in the return periods of 475 and 2475 years are compared with the observed ground response and the design spectra recommended by the Iranian seismic code (for site classes Types I and II). Several geotechnical boreholes from the previous works in the affected area were analyzed through the equivalent-linear site response approach in order to obtain the seismic response at the soil surface. The results are then compared with the code design spectra for the site classes of Types III and IV. It is demonstrated that the calculated response spectra are generally larger than those recommended by the Iranian seismic code, especially for the 4–7 stories buildings.

2017年11月12日，在伊朗西部的萨尔波勒·扎哈卜市发生了强烈地震，其震级为（\（M _ {{\ text {w}}} \\））7.3，焦深18 km。在Sarpol-e Zahab站记录到的最大水平地面峰值加速度为0.69 g。在框架和砖石建筑中观察到了明显的破坏，而在这个小城市中破坏的分布并不均匀。初步现场勘测表明，在某些地区，许多工程结构坍塌或严重受损，而在其他地区，那些在地震期间仍完好无损的非结构砖石建筑则与此相反。本文是地震发生几天后，通过作者进行的实地考察准备的初步勘察报告。然后，受灾城市及周边地区强大地面运动台站记录的数据，以及从Sarpol-e Zahab的可用钻孔中收集到的岩土数据，都被用于概率地震危险性和局部场地效应分析。将在两个站点观测到的响应谱和地面加速度的距离相关性与某些衰减模型预测的响应谱进行了比较。将475年和2475年回归期的概率地震危险性分析结果与观察到的地面响应和伊朗地震法规（针对I类和II类场地）推荐的设计频谱进行了比较。通过等效线性场地响应方法分析了受灾地区先前工作中的几个岩土钻孔，以获得土壤表面的地震响应。然后将结果与类型III和IV的场所类别的代码设计频谱进行比较。结果表明，计算得出的响应谱通常比伊朗地震法规建议的要大，特别是对于4-7层建筑物。