Seismic Imaging of the Salt Lake Basin through Joint Inversion of Receiver Functions and Rayleigh wave Ellipticity

Fan-Chi Lin, HyeJeong Kim, James Pechmann, Adam McKean, & Christian Hardwick

Published September 8, 2024, SCEC Contribution #13899, 2024 SCEC Annual Meeting Poster #045

The Wasatch Front has the potential to generate large-magnitude, damaging earthquakes. Salt Lake City, the capital and most populous city of Utah, and its surrounding area are particularly prone to earthquake hazards due to the slow-velocity sediment layer deposited by Late Pleistocene Lake Bonneville. In the Salt Lake Basin, the Wasatch Front Community Velocity Model has been used for shaking hazard assessments based on realistic earthquake rupture scenarios. However, the model was primarily built using valley-wide gravity measurements with limited well and seismic constraints. In this study, we construct a sediment layer velocity model by taking advantage of the recently improved coverage from permanent and temporary seismic arrays. We perform receiver function analysis and jointly invert the first peaks of receiver functions and the Rayleigh wave ellipticity, both of which are sensitive to shallow sedimentary structures, to construct a shallow basin velocity model. Our new model reveals thicker sediment in the area bounded by the East Bench Fault and the West Valley Fault Zone, an antithetic normal fault system. We demonstrate that the new seismic velocity model better explains the observed gravity in the valley. Additionally, our receiver function analysis shows that sediment thickness can change sharply across the East Bench Fault, which can be used to infer the offset and onset of fault movement.

Key Words
CVM, Receiver function, surface wave, basin

Citation
Lin, F., Kim, H., Pechmann, J., McKean, A., & Hardwick, C. (2024, 09). Seismic Imaging of the Salt Lake Basin through Joint Inversion of Receiver Functions and Rayleigh wave Ellipticity. Poster Presentation at 2024 SCEC Annual Meeting.

Related Projects & Working Groups
Seismology