Seismic Monitoring of Baseflow and Groundwater Changes in the Yellowstone National Park

Abstract Relative seismic velocity changes are being increasingly used to monitor changes in groundwater. However, it remains challenging to verify its implementation in watersheds without direct groundwater well measurements. In this study, we conduct a 12‐year observation in a watershed of the Yellowstone National Park (YNP). We find that the seasonal fluctuations and long‐term trend of the measured are highly correlated with the estimated baseflow, which serves as a constraint for groundwater changes. We integrate the estimated baseflow into a poroelastic mechanism and conduct two simulations based on pressure diffusion. These simulations closely match with our observed variations. In addition, our analysis suggest that the measured is primarily influenced by hydrologic pressure diffusion rather than surface air temperature. We conclude that the baseflow analysis can further enhance the seismic monitoring of groundwater changes.