On October 30th 2020, a M7.0 earthquake occurred in the Aegean Sea close to Samos Island (Greece) and the western coast of Turkey that had a strong impact on the city of İzmir, about 70 km away from the epicenter. 116 people were killed, several hundreds were injured and about 4% of the structures sustained damages, including buildings that totally collapsed. Strong amplification of ground motion within Bornova basin (İzmir) where severe damages were observed, has been reported among the detrimental factors that may have contributed to such earthquake losses. This study is devoted to providing evidence that the reason of the observed intensity of ground motion in Bornova basin is mainly related to site effects and in particular to what is referred to as basin effects. The evaluation of observations for basin effects is based on a analysis with empirical techniques in frequency domain as well as with time–frequency analyses to reveal the contribution of different wave types in the response. Empirical findings are correlated with the particular geological structure of the Bornova basin, the latter being enhanced with a representative deep V_S model using surface wave inversion on strong motion recordings. Furthermore, empirical findings are validated with 2D numerical analyses of a simplified basin model. Building characteristics and structural damages are also discussed in an attempt to comprehend the relation between them and basin effects. Noting that basin effects are not explicitly included in any modern seismic code, an approach is proposed to introduce the extra amplification due to basin effects in design practice.

2020年10月30日，靠近萨摩斯岛（希腊）和土耳其西海岸的爱琴海发生M7.0级地震，对距震中约70公里的伊兹密尔市造成强烈影响。116 人遇难，数百人受伤，约 4% 的建筑物受损，包括完全倒塌的建筑物。在观察到严重破坏的博尔诺瓦盆地（伊兹密尔）内，地面运动的强烈放大已被报告为可能导致此类地震损失的不利因素之一。本研究致力于提供证据，证明在博尔诺瓦盆地观测到的地震动强度的原因主要与场地效应有关，特别是与所谓的盆地效应有关。盆地效应的观测评估基于频域中的经验技术分析以及时频分析，以揭示不同波浪类型在响应中的贡献。经验发现与博尔诺瓦盆地的特定地质结构相关，后者被具有代表性的深 V在强运动记录中使用表面波反演的_S模型。此外，实证结果通过简化盆地模型的二维数值分析得到验证。还讨论了建筑特征和结构损坏，以试图理解它们与盆地效应之间的关系。注意到盆地效应未明确包含在任何现代地震规范中，建议采用一种方法在设计实践中引入由于盆地效应引起的额外放大。