TIME LAPSE ELECTRICAL RESISTIVITY TOMOGRAPHY OF TIDAL PUMPING OF NEARSHORE GROUNDWATER FROM GRAHAMS HARBOR, SAN SALVADOR ISLAND, BAHAMAS
Comparing apparent resistivity for each dataset against the initial dataset for each suite of profiles, we demonstrate that total apparent resistivity is sinusoidal with a range of values that is 20% of the maximum value. Changes are three hours out of sync with the predicted tides and consistent with a mixed semi-diurnal tide pattern. Inversion models in R2 illustrate the spatial arrangement of changes to earth resistivity during the tidal cycle. Difference plots between each modeled dataset and the initial modeled data reveal that changes to resistivity are restricted to the upper 10 meters of the transect and expectedly more pronounced closer to the shoreline.