Improving the resolution of investigation using ERT instruments with a reduced number of electrodes

Abstract

Since electrical resistivity tomography (ERT) is a standard geophysical method widely used in scientific and technological domains, many efforts have centered on improving its accuracy. The advantage of this method is its great capacity to combine and manage a high number of electrodes at the same time. A larger number of electrodes allows more possible array combinations and therefore, multiplies the number of acquisition points improving both horizontal and vertical resolution. However, in some cases, an instrument with a high capacity of electrodes is not available reducing the quality of the acquisitions. In this study, we present a new technique that improves the resolution of ERT using instrument with a limited number of electrodes. As happens with the roll-along technique, the proposed method allows to perform several concatenated profiles and summon all the data in a master profile for its inversion. This new technique improves resolution with new measures allowing to work with a reduced budget, low acquisition times and without the need of a big workforce in the field. To prove the capabilities of the method, synthetic, laboratory and field data were used to compare the results of the inversions to a previously known model using a statistical approach. The results show improvements of up to 80% compared to the same instrument used in a traditional way when only a limited instrument is available.