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Mapping Los Angeles basin depth with converted seismic phases recorded by dense arrays

Yan Yang, & Robert W. Clayton

Submitted September 10, 2023, SCEC Contribution #13003, 2023 SCEC Annual Meeting Poster #202

The depth of the Los Angeles Basin, one of its least accurately determined attributes, holds significance for both tectonic studies and for defining the resonant period of the basin for site amplification – a key factor for the structural safety of downtown Los Angeles's skyscrapers. To map the basin depth, we employed two dense arrays: The Community Seismic Network (CSN), a strong-motion network of ~400 low-cost accelerometers in schools across LA, and the Los Angeles Basin Node Survey 2022 (LAB2022), consisting of ~300 geophones deployed for a month in mid-2022. Utilizing differential travel times between direct S and converted Sp phases of local earthquakes, we map the LA basin's depth. Our results with denser data coverage provide independent constraints that supplements previous seismic tomography and gravity surveys. Our mapping suggests that the Central Trough of the LA Basin is deeper than the previously assumed 9 km.

Yang, Y., & Clayton, R. W. (2023, 09). Mapping Los Angeles basin depth with converted seismic phases recorded by dense arrays. Poster Presentation at 2023 SCEC Annual Meeting.

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SCEC Community Models (CXM)