Increasing the effectiveness of electrical resistivity tomography using γ_11n configurations

Abstract

A new array type, i.e., the γ11n arrays, is introduced in this paper, in which the sequence of the current (C) and potential (P) electrodes is CPCP, and the distance between the last two electrodes is n times the distance between the first two ones and that of the second one and the third one. These arrays are called quasinull arrays because they are—according to their array and behaviour—between the traditional and null arrays. It is shown by numerical modelling that, in detecting small‐effect inhomogeneity, these configurations may be more effective than the traditional ones, including the optimized Stummer configuration. Certain γ11n configurations—especially the γ112, γ113, and γ114—produced better results both in horizontal and vertical resolution investigations. Based on the numerical studies, the γ11n configurations seem to be very promising in problems where the anomalies are similar to the numerically investigated ones, i.e., they can detect and characterize, e.g., tunnels, caves, cables, tubes, abandoned riverbeds, or discontinuity, in a clay layer with greater efficacy than those of the traditional configurations. γ11n measurements need less data than traditional configurations; therefore, the time demand of electrical resistivity tomography measurements can be shortened by their use.

Field Applicability of the g11n Configuration

“…The EarthImager software proved to be appropriate to handle such data if they were generated by the program itself and if the effect of the inhomogeneity was not large. Figure 3 presents images which has been created by 8 th Congress of the Balkan Geophysical Society 5-8 October 2015, Chania, Greece these arrays and by the Wenner- and the optimised traditional array, the Stummer array (from Szalai et al 2015). In many examples -like also in the here presented one -the  arrays, or many of them produced better results than even the optimised traditional array.…”

The First Inversion Results with the g11n Configuration

“…The EarthImager software proved to be appropriate to handle such data if they were generated by the program itself and if the effect of the inhomogeneity was not large. Figure 3 presents images which has been created by these arrays and by the Wenner- and the optimised traditional array, the Stummer array (from Szalai et al 2015). In many examples -like also in the here presented one -the  arrays, or many of them produced better results than even the optimised traditional array.…”

Multiplication of the depth of detectability using γ11n arrays

“…A number of numerical examples are presented in Szalai et al, (2014). Here just some examples will be shown to validate their suitability.…”