NEW WAYS FOR THE INTERPRETATION OF GEOELECTRICAL RESISTIVITY MEASUREMENTS IN THE SEARCH FOR AND DELIMITATION OF AQUIFERS |
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| Authors: | H FLATHE |
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| Institution: | Bundesanstalt für Bodenforschung , Hannover |
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| Abstract: | Abstract Geoelectric resistivity measurements by means of direct current for solving hydrogeological problems have become increasingly significant in recent years. Measurements on the surface according to the four-point-method (SCHLUMBERGER or WENNER arrangement) result in so-called “apparent” resistivities ? α as a function of the electrode distance L. The evaluation of these measuring data, here in form of sounding graphs ? α(L/2), consists of the determination of true resistivities as a function of the depth z. Since a direct computation of ? (z) from α (L/2) is not possible in practice, theoretically computed master curves constitute the essential auxiliary means for the evaluation. New simplified calculation techniques allow to establish accurately computed master curves for an underground consisting of more than three layers. By means of such standard graphs special problems of hydrogeology can quantitatively be solved by applying geoelectrical methods. The procedure is demonstrated on hand of complicated cases of aquifers devided into several storeys. |
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| Keywords: | flood frequency forest fires uncertainty analysis derived distribution approach Monte Carlo simulation Latin Hypercube sampling generalized extreme value distribution SCS-CN method rational method Torrent Giannoula Attica Greece |
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