VS30 is currently used as a key proxy to parameterize site response in engineering design and other applications. However, it has been found that VS30 is not an appropriate proxy, because it does not reliably correlate with site response. Therefore, the VS30‐based National Earthquake Hazards Reduction Program site maps may not capture regional site responses. In earthquake engineering, site resonance, which can be characterized by the fundamental mode with a site period (⁠Tf⁠) and its associated peak amplification (⁠A0⁠), is the primary site‐response concern. Mapping Tf and A0 is thus essential for accurate regional seismic hazard assessment. We developed a 3D shear‐wave velocity model for the Jackson Purchase Region of western Kentucky, based on shear‐wave velocity profiles interpreted from seismic reflections and refractions, mapped geologic units, and digital‐elevation‐model datasets. We generated shear‐wave velocity profiles at grid points with 500 m spacing from the 3D model and performed 1D linear site‐response analyses to obtain Tf and A0⁠, which we then used to construct contour maps for the study area. Our results show that Tf and A0 maps correlate with the characteristics of regional geology in terms of sediment thicknesses and their average shear‐wave velocities. We also observed a strong dependency of A0 on bedrock shear‐wave velocities. The mapped Tf and A0 are consistent with those estimated from borehole transfer functions and horizontal‐to‐vertical spectral ratio analyses at broadband and strong‐motion stations in the study area. Our analyses also demonstrate that the depth to bedrock (⁠Zb⁠) is correlated to Tf⁠, and the average sediment shear‐wave velocity (⁠VS‐avg⁠) is correlated to A0⁠. This implies that Zb and VS‐avg may be considered as paired proxies to parameterize site resonance in the linear‐elastic regime.

中文翻译：

---

从厚沉积物中绘制基本模式站点周期和放大图：以美国中部西肯塔基州杰克逊采购区为例

VS30 目前在工程设计和其他应用中用作参数化站点响应的关键代理。但是，已经发现 VS30 不是合适的代理，因为它与站点响应没有可靠的关联。因此，基于 VS30 的国家地震减灾计划站点地图可能无法捕捉区域站点响应。在地震工程中，场地共振可以用具有场地周期的基本模式 (⁠Tf⁠) 及其相关的峰值放大 (⁠A0⁠) 来表征，是主要的场地响应问题。因此，绘制 Tf 和 A​​0 对准确的区域地震危险性评估至关重要。我们基于从地震反射和折射解释的横波速度剖面，为肯塔基州西部的杰克逊购买地区开发了一个 3D 横波速度模型，映射的地质单元和数字高程模型数据集。我们在与 3D 模型相距 500 m 的网格点处生成横波速度剖面，并执行一维线性场地响应分析以获得 Tf 和 A​​0，然后我们用它们来构建研究区域的等高线图。我们的结果表明，Tf 和 A​​0 地图与区域地质特征在沉积厚度及其平均横波速度方面相关。我们还观察到 A0 对基岩横波速度的强烈依赖性。映射的 Tf 和 A​​0 与研究区宽带和强震台站的钻孔传递函数和水平垂直光谱比分析估计的结果一致。我们的分析还表明，基岩深度 (⁠Zb⁠) 与 Tf⁠ 相关，平均沉积物横波速度 (⁠VS-avg⁠) 与 A0⁠相关。这意味着 Zb 和 VS-avg 可以被视为成对代理来参数化线弹性区域中的站点共振。