Electrical resistivity is a fundamental specific property of a material that measures its electrical resistance or how strongly it resists electric current. It is a measure of a materials property to oppose the flow of electric current. The resistivity of a material is expressed in ohm-meters (Ω⋅m) and is represented by the Greek letter ρ (rho) . A low resistivity indicates a material that readily allows electric current to flow through it, while a high resistivity means that a material does not conduct electric charge well.

Electrical resistivity is an intrinsic property of a material and does not depend on geometric properties of a material, unlike resistance. It is determined by passing an electric current through a specimen and then measuring the resultant voltage drop over a certain length. It is expressed by the relationship between the electrical field inside the material and the flowing electric current. The SI unit of electrical resistivity is the ohm-meter (Ω⋅m) .

Electrical resistivity methods involve injecting electrical current into the subsurface via two current electrodes and measuring the potential. Electrical resistivity methods can be used to detect lateral and/or vertical variations in certain subsurface electrical properties (i.e., resistivity or its inverse, conductivity) .

In summary, electrical resistivity is a measure of a materials property to oppose the flow of electric current, expressed in ohm-meters (Ω⋅m). It is an intrinsic property of a material and does not depend on geometric properties of a material. Electrical resistivity methods can be used to detect variations in certain subsurface electrical properties.