Improved measurements of the apparent resistivity for small depths in Vertical Electrical Soundings

•Vertical Electrical Sounding by using bare conductive rods as electrodes•A simple procedure for measuring the apparent resistivity at any distance•Substantial improvement of small vertical depth soundings•Reducing uncertainty in choosing the most appropriate soil model

In this work, a full simulation of a Vertical Electrical Sounding of a multilayer soil using a Wenner array is performed when both the active and the measurement electrodes consist of bare rod length L buried vertically at ground level. The apparent resistivity is calculated for a wide range of values of the separation between the electrodes using the values of the potential between the measuring electrode and a proposed function that characterizes the behavior of the electrodes used which substantially improves the measurements for small depths. The results allow comparing the values of apparent resistivity obtained by known calculation expressions with the results found by using a characteristic function of the electrodes, which is proposed in this paper. In order to obtain a complete vertical sounding of the soil, the convenience of using adapted methods to the type of electrode used in the sounding is discussed.