Multi-scale seismic imaging of the Ridgecrest, CA, region with full-waveform inversions of regional and dense array data

Guoliang Li, & Yehuda Ben-Zion

Published September 10, 2023, SCEC Contribution #12782, 2023 SCEC Annual Meeting Poster #039

We describe a methodology for developing multi-scale seismic velocity models with waveform inversions using earthquake and ambient noise data recorded by regional and dense sensor configurations. The method is illustrated for the area around the rupture zone of the 2019 Ridgecrest earthquake sequence in California, utilizing data recorded by the regional network and dense 2D and 1D deployments with station spacings of ~5 km and ~100 m, respectively. Starting with regional Vp, Vs models (Fang et al., 2022) and locations of Ridgecrest aftershocks (White et al., 2021), the velocity models and event locations are improved iteratively by inversions of waveforms recorded by regional stations and the 2D array, using a minimum Gauss-Lobato-Legendre (GLL) distance of ~150 m. Waveforms from many local events are recorded by the dense 1D arrays with high SNR for frequencies of 10 Hz or more, capable of resolving small-scale features with size of ~50 m or less. Using these data, the velocity models for the Ridgecrest rupture zone and shallow crust are refined by updating the improved regional Vp, Vs models with waveform inversions using a local GLL point distance of 20 m. The derived velocity models provide self-consistent descriptions of the Ridgecrest rupture zone and the shallow crust embedded in the regional Vp, Vs structures. The results can be used to improve earthquake source properties, simulated dynamic ruptures and ground motions, and the understanding of fault structures and processes in the region.

Key Words
mult-scale imaging, adjonit tomography, fault zone structure

Citation
Li, G., & Ben-Zion, Y. (2023, 09). Multi-scale seismic imaging of the Ridgecrest, CA, region with full-waveform inversions of regional and dense array data. Poster Presentation at 2023 SCEC Annual Meeting.

Related Projects & Working Groups
Seismology