Mapping Los Angeles Basin Depth With Sp Converted Phases
Abstract
The depth of the Los Angeles (LA) basin is a critical factor for seismic hazard assessment and active tectonic studies. By analyzing S‐waves generated by earthquakes below the basin that convert to P‐waves at the sediment‐bedrock interface, we estimate the maximum depth of the LA basin to be 9 km. This estimate depends on the velocities within and below the basin, and the depth presented here is based on the latest community velocity model. To map the basin depth, we use two dense arrays: the Community Seismic Network, a dense network of low‐cost accelerometers in schools across LA region, and a basin‐wide node survey conducted in 2022, consisting of about 300 geophones deployed for a month. Utilizing differential travel times between direct S and Sp converted phases of local earthquakes, we produce a detailed depth map of the LA basin.
Copyright and License
© 2024. The Author(s). This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Acknowledgement
The authors thank the LAB2022 deployment team who make all the field work. The authors thank helpful discussion with Qiushi Zhai, Weiqiang Zhu, and Ettore Biondi. The authors thank Valeria Villa for providing digitalized maps of Repetto and Mohnian interfaces. This research was funded by the Southern California Earthquake Center (SCEC) award 22019.
Funding
This research was funded by the Southern California Earthquake Center (SCEC) award 22019.
Data Availability
The event data used in the research are all publicly available on CSN website (http://csn.caltech.edu/data/). The depth model and phase picks are made publicly available at Yang (2024). These will allow the results to be converted to any velocity model and allow new events to be added.
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Additional details
- Southern California Earthquake Center
- 22019
- Available
-
2024-09-13Available Online
- Accepted
-
2024-09-08Manuscript Accepted
- Caltech groups
- Division of Geological and Planetary Sciences, Seismological Laboratory
- Publication Status
- Published