Determination of Near Surface Shear-Wave Velocities in the Central Los Angeles Basin with Dense Arrays

Zhe Jia, & Robert W. Clayton

Submitted August 14, 2020, SCEC Contribution #10618, 2020 SCEC Annual Meeting Poster #047

The shallow velocity structure of the Los Angeles (LA) Basin plays an important role in the seismic hazard of this populated area. Most existing velocity models of the LA Basin are derived from sonic logging, industry reflection profiles or sparse array tomography and are limited by spatial coverage of seismic stations, and the depth extent of wells. Here we investigate the shallow shear wave velocity structure of the LA Basin with ambient noise correlations between the five oil industrial dense arrays and 21 Southern California Seismic Network (SCSN) broadband stations. We observe clear fundamental mode and first overtone Rayleigh wave of 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. The detailed shallow velocity structure is well resolved, and the Newport-Inglewood fault is characterized by sharp velocity changes.

Citation
Jia, Z., & Clayton, R. W. (2020, 08). Determination of Near Surface Shear-Wave Velocities in the Central Los Angeles Basin with Dense Arrays. Poster Presentation at 2020 SCEC Annual Meeting.


Related Projects & Working Groups
Seismology