Determination of Near Surface Shear‐Wave Velocities in the Central Los Angeles Basin With Dense Arrays.

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. Key Points: We derive top 3 km Vs structure of the central Los Angeles Basin using dense industrial arrays correlated with broadband seismic stationsOur model better resolves small scale heterogeneities and better predicts dispersion observations compared with the SCEC CVM modelsOur model illuminates the Newport‐Inglewood fault zone by a NW–SE trending high shear wave velocity belt [ABSTRACT FROM AUTHOR]