In this study, we investigate the shallow shear wave velocity structure of the Los Angeles Basin in southern California, using ambient noise correlations between 5 dense arrays and 21 broadband stations from the Southern California Seismic Network (SCSN). We observe clear fundamental mode and first overtone Rayleigh waves in the frequency band 0.25–2.0 Hz, and obtain group velocity maps through tomography. We further derive a 3D shear wave velocity model, covering a large portion of the central LA Basin for the depths shallower than 3 km. We found that the small scale shallow velocity structure heterogeneities are better resolved compared with the SCEC Community velocity models. Our model captures the presence of the Newport‐Inglewood fault by a NW–SE trending high velocity belt. Our model provides more accurate constraints on local ground motion predictions with detailed mapping of structural heterogeneities.

中文翻译：

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用密集阵列确定洛杉矶中部盆地近地表横波速度

在这项研究中，我们使用南加州地震台网（SCSN）的5个密集阵列与21个宽带站之间的环境噪声相关性，研究了加利福尼亚南部洛杉矶盆地的浅剪切波速度结构。我们在0.25–2.0 Hz频段观察到清晰的基本模式和第一泛音瑞利波，并通过层析成像获得了群速度图。我们进一步推导了一个3D剪切波速度模型，该模型覆盖了LA盆地中部大部分深度小于3 km的深度。我们发现，与SCEC社区速度模型相比，小规模浅层速度结构的异质性得到了更好的解决。我们的模型通过NW–SE趋势高速带捕获了Newport-Inglewood断层的存在。