The shear-wave (S-wave) structures of shallow marine sediments are important for offshore geotechnical studies, deep crustal S-wave imaging, multicomponent seismic exploration, and underwater acoustics studies. We have applied the multicomponent Scholte-wave analysis technique to an active-source shallow marine seismic profile in the East China Sea. Scholte waves have been excited by shots from a 5450 inch³ air-gun array and their recordings have been conducted at the seafloor using ocean bottom nodes (OBNs). First, we extract the common-receiver gathers (CRGs) and correct for the time drift simultaneously using a forward and inverse fast Fourier transform resampling algorithm. Three CRGs of seismic sensors are used for Scholte-wave analysis. Raw sensor CRGs are rotated to the inline, crossline, and vertical coordinate system. The rotated tilt and roll angle are directed using the inner electric compass log value, and the shot inline azimuth is estimated using the particle motion method. Then, the velocity spectra are calculated from the inline and vertical components using the phase-shift method. Higher Scholte-wave modes dominate on the horizontal components, whereas the stronger fundamental mode dominates on the vertical components. The multicomponent velocity spectrum stacking method is adopted to produce the final dispersion energy image. Up to four modes of dispersion curves are retrieved within the 1.1–4.3 Hz frequency band. The multimode dispersion curve inversion is constructed for imaging the shallow sediments. The results suggest a low $V_{\mathrm{S}}$ of 180–650 m/s and few lateral variations within the top 0.5 km of shallow marine sediments in the East China Sea. This model can provide an important reference for offshore geotechnical investigations, especially for OBN multicomponent seismic exploration data processing. The use of OBNs has high feasibility in $V_{\mathrm{S}}$ imaging for shallow marine sediments when combined with the Scholte-wave dispersion-curve inversion.

中文翻译：

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利用OBN多分量舒波资料对东海浅层沉积物S波结构进行地震成像。

浅海沉积物的剪切波（S波）结构对于海上岩土工程研究，深地壳S波成像，多分量地震勘探和水下声学研究非常重要。我们已经将多分量舒尔特波分析技术应用于东海的有源源浅海地震剖面。5450英寸³拍摄的照片激发了Scholte浪潮³气枪阵列及其记录是使用海底节点（OBN）在海底进行的。首先，我们使用前向和反向快速傅里叶变换重采样算法提取公共接收器集合（CRG）并同时校正时间漂移。地震传感器的三个CRG用于Scholte波分析。原始传感器CRG旋转到内联线，交叉线和垂直坐标系。使用内部电子罗盘对数值指示旋转的倾斜和横滚角，并使用质点运动方法估算发射的直列方位角。然后，使用相移法根据轴向分量和垂直分量计算速度谱。较高的舒尔特波模在水平分量上占主导地位，而较强的基本波模在垂直分量上占主导地位。采用多分量速度谱叠加法生成最终的色散能量图像。在1.1–4.3 Hz频带内，最多可以找到四种模式的色散曲线。构建了多模色散曲线反演，对浅层沉积物进行成像。结果表明低$V_{\mathrm{小号}}$在东海最浅的海相沉积物的前0.5 km内，速度为180–650 m / s，横向变化很小。该模型可为海上岩土工程勘察提供重要参考，特别是对OBN多分量地震勘探数据处理。OBN的使用在以下方面具有很高的可行性$V_{\mathrm{小号}}$ Scholte波频散曲线反演结合对海底浅层沉积物进行成像。