ERT Survey for an archaeological survey

ERT Survey at an urban environment

2D resistivity model to study the foundations of a building

Electrical resistivity is one of the fundamental properties of all materials. Measured resistivities in Earth materials are primarily controlled by the movement of charged ions in pore fluids. Water itself is not a good conductor of electricity. However, ground water generally contains dissolved elements that increase its ability to conduct electricity. Hence, porosity and fluid saturation tend to dominate electrical resistivity measurements. In addition to pores, fractures within crystalline rock can lead to low resistivities if they are filled with fluids. There is a large range of resistivities (from 10-3Ohm.m in some ore-bearing minerals to 1014 in pure quartz crystals) making resistivity an excellent property to describe the materials beneath the surface. Geophysical methods based on electrical principles were developed in the 1900s and are currently used in many applications as the search for suitable groundwater sources, mining, archeology, location of cavities, among others. These methods are helpful to investigate the near-surface in 2D and 3D mapping, unraveling the electrical resistivity of geological materials, getting vertical and lateral variations of resistivity along profiles, depending of the electrode position and separation. Listed below are some of those techniques: