The South Carolina Coastal Plain consists of deep soil sediments over basement bedrock. The depth of basement bedrock varies from being present at the surface to a depth of more than 1200 m at the southern tip of the state. A large variation exists in the thickness of the sediment, which impacts the seismic site response analyses of the Coastal Plain, particularly in areas where the availability of deep shear‐wave velocity profiles is limited. This study evaluates the impact of variations in the shear‐wave velocity profiles for two sites in the South Carolina Coastal Plain. The shear‐wave velocity profiles were measured using different geophysical methods, including a combined multichannel analysis of surface waves and microtremor array measurement (MASW‐MAM) method and P–S suspension logging. The equivalent‐linear site response analyses were conducted by applying a synthetic earthquake motion at the depth of the B–C boundary (a depth of competent rock in which the shear‐wave velocity is 760 m/s). The results are presented in terms of the amplification factor and its standard deviation. Results show that the average shear‐wave velocity at the first 30 m (⁠VS30⁠), the shear‐wave velocity contrast at the interface of the base layer and the B–C boundary, and the depth to the B–C boundary have a significant impact on the amplification factor and its variability, particularly for the amplification factor at periods higher than 0.1 s. The MASW‐MAM method provided significantly lower VS30 values than the P–S suspension logging method at one of the two sites. Consequently, an additional peak in the amplification factor was observed for the site that had a low VS30⁠, and the corresponding period was close to the resonant period of the loose, surface deposit.

中文翻译：

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南卡罗来纳州沿海平原深层土壤剖面现场响应分析的不确定性评估

南卡罗来纳州沿海平原由地下基岩上的深层土壤沉积物组成。基底基岩的深度从存在于地表到该州南端超过 1200 m 的深度不等。沉积物的厚度存在很大的变化，这会影响沿海平原的地震现场响应分析，特别是在深横波速度剖面的可用性有限的地区。本研究评估了南卡罗来纳州沿海平原两个地点的横波速度剖面变化的影响。横波速度剖面是使用不同的地球物理方法测量的，包括表面波多通道分析和微震阵列测量（MASW-MAM）方法和 P-S 悬浮测井法。等效线性场地响应分析是通过在 B-C 边界深度（剪切波速度为 760 m/s 的有效岩石的深度）应用合成地震运动进行的。结果以放大因子及其标准偏差表示。结果表明，前 30 m 处的平均横波速度（⁠VS30⁠）、基层与 B-C 边界界面处的横波速度对比以及到 B-C 边界的深度有对放大系数及其可变性的显着影响，特别是对于高于 0.1 s 的时间段的放大系数。在两个站点之一，MASW-MAM 方法提供的 VS30 值明显低于 P-S 悬浮测井方法。最后，