Seismic Velocity Variations Illustrate Hydrological and Ecohydrological Processes in a Mountain Watershed

Abstract We employ passive seismic interferometry to study seismic hydrological responses in a snowmelt‐driven, semi‐arid catchment. Seismic velocity changes (dv/v) at 2–4 Hz and 4–8 Hz are analyzed from six stations along a hillslope transect between May and November 2023 and compared to precipitation, soil moisture, and groundwater level timeseries. Variation in dv/v correlates with groundwater level and mirrors seasonal catchment wetting and evapotranspiration. Correlations between dv/v and groundwater are stronger at stations on the cooler, wetter, north‐facing hillslope than on the warmer, drier, south‐facing hillslope, consistent with expected recharge and evapotranspiration patterns. Different dv/v behaviors across two bands suggest depth‐dependent pore‐pressure changes, outlining different hydrologic zones. These findings highlight the utility of dv/v measurements in detecting laterally supplied water inputs, providing insight into local vertical water losses, effectively tracking groundwater–vegetation interactions, and supporting ecohydrological research and water management in semi‐arid snowmelt systems.