Resumen

ARORA, Tanvi. Variographic Analysis of the Electrical Structure of South Indian Unsaturated Zone. Ser. correl. geol. [online]. 2021, vol.37, n.2, pp.11-20. ISSN 1666-9479.  http://dx.doi.org/10.5281/zenodo.5708158.

Introduction: Structural analysis to determine the variability of a parameter field is a basic and essential step to be performed in geostatistical estimation or simulation of a parameter. Variographic analysis provides lot of information about the nature of the variable. This is performed in two steps viz., calculation of an experimental covariance/variogram and its modeling with theoretical one. The practical formula for calculating the experimental variogram needs translation of expected value to an arithmetic mean (Ahmed, 1995). This implies having sufficient number of pairs for each lag and the conventional procedure of calculating variogram does not have any control over the number of pairs. The present work provides a new approach for determination of experimental variograms with the desired number of pairs for each lag, which comprises an efficient and entirely new way of calculating variograms by keeping a control over the number of pairs.

The unsaturated zone is extremely important for the estimation of groundwater potential, but at the same time it is a complex medium to characterize, to understand the processes taking place and to quantify the flow through it. Therefore, the problem is addressed through an integrated approach. Although a large number of parameters from various processes play a role in recharge, the present work has been concerned with moisture content and resistivity in a vertical profile measured repeatedly using Neutron Probe and Time-Lapse Electrical Resistivity Tomography (TLERT), respectively. The time interval has been taken not uniformly, but as a function of the rainfall event. A unique application of Geostatistics has been made to bring the two different types of datasets onto a common platform. The application of geostatistics has also helped to analyses the spatial and temporal variability of these parameters, which helps to understand their contribution and the uncertainty involved.

Palabras clave : Variography Unsaturated Zone; Resistivity.

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