INVESTIGATING THE EFFECTIVENESS OF INNOVATIVE ELECTRODES FOR ERT SURVEYS

Abstract: Electrical Resistivity Tomography (ERT) is a well-established, non-invasive geophysical technique widely used for near-surface investigations. However, deploying traditional stainless-steel spike electrodes is often slow and logistically challenging, especially in complex and rugged terrains like permafrost or coarse-rocky debris materials.  The process of hammering (installing) spike electrodes into such uneven, coarse- ground at high elevations or on rough terrain becomes challenging due to logistics, limited access, and the inherent weight of the equipment.  These limitations, combined with long deployment times and difficulties achieving good electrical contact with the ground, hinder the full potential of ERT for achieving rapid and reliable surveys in these challenging environments. This research introduces promising innovative electrode designs, specifically conductive textile and steel net electrodes, as an alternative to standard stainless-steel spikes. These lighter, larger-surface-area electrodes offer several benefits in challenging environments. They can be deployed more easily and quickly, reducing the time and effort needed to set up ERT sounding and decreasing the water required for wetting electrodes. Additionally, during measurements, they may improve data quality by reducing contact resistance and enhancing signal strength (signal-to-noise ratio). The potential of these new electrode designs is demonstrated through ERT measurements using three ERT-sounding profiles: traditional stainless-steel spikes (baseline), net, and conductive textile electrodes. All electrodes were tested at a designated site using a dipole-dipole array configuration with different skips and a wetting approach (sponge/salt water). We compared the performance and reliability of each electrode type measurement with a statistical analysis of factors such as contact resistances, injected electrical current, anticipated error, and the resulting inverted resistivity models. This research underscores the innovative nature of advancements in electrode design. The realization of these proposed electrodes is assessed to show promise for improving data quality, reducing survey costs, and decreasing deployment time, which could enable more rapid and accurate acquisition of extended survey lines and significantly expand the applicability of ERT. This research is a testament to the potential of innovation in overcoming the challenges of near-surface investigations in challenging coarse-blocky terrains, and we hope that it will inspire further advancements and solutions in this field.