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The California-Nevada Adjoint Simulations (CANVAS) Model

Claire D. Doody, Arthur J. Rodgers, Michael Afanasiev, Christian Boehm, Lion Krischer, Andrea Chiang, & Nathan Simmons

Submitted September 10, 2023, SCEC Contribution #12804, 2023 SCEC Annual Meeting Poster #198

Though high-resolution adjoint waveform tomography (AWT) models exist for southern California, a statewide model has not been previously reported. Therefore, we present the California-Nevada Adjoint Simulations (CANVAS) model, an AWT model of the crust and uppermost mantle of California and Nevada. We used WUS256 (Rodgers et al., 2022) as a starting model; we ran 161 iterations in 5 period bands beginning at 30-100 seconds and ending at 12-60 seconds. At 20 seconds minimum period, we inverted moment tensors using mttime (Chiang, 2020) to better constrain source parameters before iterating at short periods. We show that updating moment tensors significantly impacts the synthetic waveform fits and is a necessary step to refine the model at shorter periods. The final model resolved known tectonic features throughout the state, and accurately determined the depths to basement of large basins throughout California (e.g., Tulare Basin, Ventura Basin). CANVAS also greatly improved waveform fits to dispersed surface waves compared to WUS256, especially for small magnitude events (MW< 4.75) and stations at great distances from the source (> 1000km). CANVAS can serve as a high-resolution starting model for smaller-scale regional seismic tomography studies across California and western Nevada.

This work was supported in part by Lawrence Livermore National Laboratory Directed Research and Development project 20-ERD-008. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-852228.

Key Words
Seismic Tomography

Doody, C. D., Rodgers, A. J., Afanasiev, M., Boehm, C., Krischer, L., Chiang, A., & Simmons, N. (2023, 09). The California-Nevada Adjoint Simulations (CANVAS) Model. Poster Presentation at 2023 SCEC Annual Meeting.

Related Projects & Working Groups
SCEC Community Models (CXM)