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Examples of transient sounding from groundwater exploration in sedimentary aquifers

D.V. Fitterman
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Abstract

Examples of the use of transient electromagnetic soundings for three ground-water exploration problems in sedimentary aquifers are given. The examples include: (1) estimating depths to water table and bedrock in an alluvium-filled basin, (2) mapping a confined fresh-water aquifer in bedrock sediments, and (3) locating a freshwater/salt-water interface in a glacial-outwash aquifer. The technique works quite well for these problems within the limitations imposed by the problem of equivalence. For thin conductive targets (S-equivalence) such as a salt-water lens, the ratio of the layer thickness to its resistivity can be determined, but not the individual layer parameters. The thickness of thin resistive zones (H-equivalence) can be resolved, but the resistivity of such layers is not well determined. The problem of H-equivalence is more severe than the S-equivalence. Equivalence imposes restrictions on the transient sounding method for some ground-water exploration problems. Model studies prior to field work can be used to assess the usefulness of the technique for a particular exploration objective.

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D.V. Fitterman. 2006-03-21. Examples of transient sounding from groundwater exploration in sedimentary aquifers. https://doi.org/10.1111/j.1745-6584.1987.tb02209.x

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