Resistivity of The Earth Materials

The purpose of geoelectrical surveys is to determine the subsurface resistivity distribution by making measurements on the ground surface. From these measurements, the true resistivity of the subsurface can be estimated. The ground resistivity is related to various geological parameters such as the mineral and fluid content, porosity and degree of water saturation in the rock. Electrical resistivity surveys have been used for many decades in hydrogeological, mining, geotechnical, environmental and even hydrocarbon exploration (Loke et al. 2011).

The Resistivity Value of Earth Materials

Basically, igneous and metamorphic rocks typically have high resistivity values. Sedimentary rocks, which are usually more porous and have higher water content, normally have lower resistivity values compared to igneous and metamorphic rocks.The resistivity of groundwater varies from 10 to 100 ohm.m. Seawater has a low resistivity values which is 0.2 ohm.m.

after Loke 2013.

Reference: Loke, M.H. 2013. Tutorial : 2-D and 3-D electrical imaging surveys