Denolle, Marine AClements, Timothy Hugh2021-11-2220212021-11-152021-11Clements, Timothy Hugh. 2021. Tracking Groundwater with the Ambient Seismic Field. Doctoral dissertation, Harvard University Graduate School of Arts and Sciences.28716616https://nrs.harvard.edu/URN-3:HUL.INSTREPOS:37370106Aquifers are vital groundwater reservoirs for residential, agricultural, and industrial activities worldwide. Tracking their state with high temporal and spatial resolution is critical for water re- source management at the regional scale yet is rarely achieved from a single dataset. Here, we show that variations in groundwater levels can be mapped in space and time using perturbations in seis- mic velocity (dv/v). We employ the computing language Julia and cloud computing resources to make daily measurements of dv/v across California from the cross-correlation and auto-correlation of the ambient seismic field. We compare our results to estimates of groundwater from groundwa- ter wells, precipitation and satellite measurements. dv/v reproduces the groundwater level changes that are marked by the multi-year depletions and rapid recharges typical of California’s cycles of droughts and floods. dv/v correlates spatially with vertical surface displacements and deformation measured with GPS and the GRACE satellite.application/pdfenGeophysicsThesis or Dissertation2021-11-220000-0001-6632-1796