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Comparative Study of Non-Invasive Electrodes for Urban Electrical Resistivity Tomography Applications
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, NSG 2025: 4th Conference on Geophysics for Infrastructure Planning, Monitoring and BIM, Sep 2025, Volume 2025, p.1 - 5
Abstract
Summary
Urbanisation poses challenges for traditional subsurface investigations, prompting the use of geophysical methods such as Electrical Resistivity Tomography. However, the deployment of conventional electrodes is often impractical in sensitive or restricted environments. This study systematically evaluates the performance of various non-invasive electrodes (e.g., NaCl and KCl gels, PVA sponges, bentonite, copper tape, and medical electrodes) on two urban surfaces under controlled laboratory conditions.
The investigated parameters included contact resistance, measurement errors (repetition and reciprocal), and signal quality over a 14 days monitoring period. Results indicate that while all electrodes eventually achieved acceptable contact resistance, the time to stabilisation and long-term reliability varied significantly. KCl electrodes demonstrated superior stability, low contact resistance, and minimal error levels, maintaining consistent performance for at least 14 days. PVA sponges, bentonite, and medical gels were almost immediately usable but degraded over time due to drying. Copper tape and medical electrodes, despite offering stable contact resistance, were unable to achieve the resistance necessary for high current injections. Reciprocal error analysis revealed greater variability compared to repetition error, highlighting the need for cautious interpretation, especially in high resistance conditions.
The study concludes that electrode selection should be adapted to both the surface type and the monitoring objective.
© EAGE Publications BV