Electrical Resistivity Tomography (ERT)

The Electric Resistivity Tomography is an advanced method that induces electric current into the ground using electrodes to measure resistivity variations in a surveyed region. This method has different electrode array configurations depending on the depth of investigation to be acquired. It can be used for searching for water bearing formation, stratigraphic correlation in oil fields, prospecting for conductive bodies, finding the depths of high or low conductive anomalous layers, finding the depth and approximate shape of resistivity anomalous ore bodies, and saturated zones, civil engineering and environmental investigations., cavities detection, dentifying the depth of low velocity sand and gravels. The ERT method is mostly affected by the geochemistry of the subsurface; therefore, it has some limitation factors like the grain size distribution and ground water chemistry

Potentials of ERT:

  1. ERT is the only archaeogeophysical method which allows preparation of 2D/3D slices/maps of the underground objects at various depths under the surface without excavation.
  2. It allows precise determination of depths of the underground objects.
  3. It allows the visualization of underground objects as radar images in real time during the measurements.
  4. It allows simultaneous geophysical exploration and archaeological excavation of the registered anomalies.
  5. It has the highest resolution over all other geophysical techniques.
  6. It can be used for scanning of vertical walls and localization of inhomogeneities in it.
  7. Registered signal can undergo for further computing for extraction of invisible details from the raw scan and graphic display of the results.
  8. It allows fast scanning of a large area. It is effective for large scale exploration with high horizontal resolution.
  9. It allows connecting of different archaeological excavations by ERT exploration of the space between them.
  10. ERT exploration can be carried out through different materials (e.g. ice, asphalt, concrete…etc.).
  11. It penetrates the subsurface down to ~ 30 m depth or more depending on the electrode spacing, used array and favorable site conditions.

Delineating Underground Water using ERT Investigation