Electrical Resistivity Primer

OutlineMotivationGeophysical ImagingSubsurface Electrical PropertiesThe Electrical Resistivity MethodSurveys and Data DisplayTimelapse Electrical Resistivity

Image interpretation

A geophysical image needs to be interpreted to answer the original question which motivated the geophysical question. Or, once we have obtained a distribution of physical properties from our inversion, this needs to be interpreted. In some cases this interpretation is straightforward. For instance, if we are looking for the water table a large increase in electrical conductivity (together with some regional hydrogeologic knowledge) would often be interpreted as the watertable.

In many other cases this interpretation will require an in depth insight into physical, chemical and biological processes occurring in the subsurface as well as the relationship between soil properties and those properties mapped by our method. The interpretation can be done either by a domain specialist (e.g. a hydrologist or geochemist) who has an understanding of geophysics, by a geophysicist who has an understanding of hydrology or geochemistry or by a team where the team members combines these different skills. The cartoons shown below show (in a simplified form) the general steps associated with this interpretation.

Interpretation figure 1Interpretation figure 2 Interpretation figure 3