The United States Geological Survey national seismic hazard maps have historically been produced for a reference site condition of VS30 = 760 m/s. For other site conditions, site factors are used, which heretofore have been developed using ground motion data and simulations for shallow earthquakes in active tectonic regions. Research results from the Next Generation Attenuation–East (NGA-East) project, as well as previous and contemporaneous related research, demonstrate different levels of site amplification in central and eastern North America (CENA) as compared to active regions. We provide recommendations for modeling of ergodic site amplification in CENA based primarily on research results from the literature. The recommended model has three additive terms in natural logarithmic units. Two describe linear site amplification: an empirically constrained VS30-scaling term relative to a 760 m/s reference and a simulation-based term to adjust site amplification from the 760 m/s reference to the CENA reference of VS = 3000 m/s. The third term is a nonlinear model that is described in a companion document. All median model components are accompanied by epistemic uncertainty models.

中文翻译：

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北美中部和东部的遍历站点放大模型

美国地质调查局国家地震危险图历来是针对 VS30 = 760 m/s 的参考地点条件制作的。对于其他场地条件，使用场地因素，迄今为止，这些因素是使用地面运动数据和活动构造区域浅层地震的模拟得出的。Next Generation Attenuation–East (NGA-East) 项目的研究结果以及之前和同时期的相关研究表明，与活跃地区相比，北美中部和东部 (CENA) 的站点放大水平不同。我们主要根据文献研究结果，为 CENA 中遍历站点扩增的建模提供建议。推荐的模型具有三个以自然对数单位表示的附加项。二描述线性位点扩增：相对于 760 m/s 参考的经验约束 VS30 缩放项和基于模拟的项，用于将站点放大从 760 m/s 参考调整为 VS = 3000 m/s 的 CENA 参考。第三项是在配套文档中描述的非线性模型。所有中值模型组件都伴随着认知不确定性模型。