Sähköresistiviteettitomografia

Sähköresistiviteettitomografia, often abbreviated as ERT or electrical resistivity tomography, is a geophysical imaging technique used to determine the subsurface electrical resistivity distribution. It is a non-invasive method that utilizes the electrical properties of the ground to create a 2D or 3D model of the subsurface. The fundamental principle involves injecting electrical current into the ground at one or more points and measuring the resulting electrical potential difference at other points. By employing various electrode configurations and applying mathematical inversion algorithms, a detailed picture of the resistivity variations in the subsurface can be reconstructed. Different geological materials have distinct resistivity values; for instance, water-saturated sediments, clays, and mineralized zones typically exhibit lower resistivity compared to dry soils, rock, or porous materials. ERT has found widespread applications in various fields, including groundwater exploration, environmental site assessment, archaeological investigations, geotechnical engineering, and mineral resource exploration. Its ability to detect anomalies such as contaminant plumes, buried structures, or variations in rock formations makes it a valuable tool for subsurface characterization. The resolution and depth penetration of ERT surveys are influenced by factors such as electrode spacing, survey geometry, and the resistivity contrast of the subsurface materials.