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Abstract LAB2022 is a new temporary array consisting of 273 geophones that was deployed in the Los Angeles basin for one month during the summer of 2022. The array was designed to improve the 3D seismic velocity model of the basin through passive seismic imaging, which is crucial for both earthquake hazard assessment and the understanding of the region’s tectonic evolution. The sensors are 3C 5 Hz Zland and Smart Solo instruments. The data has been archived at the EarthScope SAGE Data Management Center and will be publicly available in summer 2025. 

Abstract This study presents a new velocity model for the Salt Lake basin (SLB) in Utah, determined using data from permanent and temporary seismic stations located on top of the basin in the Salt Lake Valley (SLV) and nearby. A three‐dimensional (3D) velocity model for the SLB is needed for accurate predictions of future damaging earthquake ground shaking in the heavily urbanized SLV, including Salt Lake City. The SLB part of the Wasatch Front community velocity model (WFCVM) currently serves this purpose. However, the current WFCVM is based primarily on gravity and borehole data with relatively few seismic constraints below depths of 100 m. In this study we use the first peak of SLV receiver functions (RFs), which is sensitive to a strong impedance contrast at the base of a semi‐consolidated sediment layer. We jointly invert the RF waveform with Rayleigh wave ellipticity (H/V) and phase velocity measurements using the Markov chain Monte Carlo approach. Our new velocity model shows a greater combined thickness of unconsolidated and semi‐consolidated sediments, compared to the WFCVM, in the northeastern SLB between the west‐dipping East Bench fault section of the Wasatch fault and the antithetic West Valley fault zone to the west. We show that the new seismic velocity model explains the gravity patterns in the valley. The new velocity model from this study provides a basis for revising the SLB model in the WFCVM.