The self-potential method

the long version

"The self-potential method is a simple yet innovative process, enabling non-intrusive assessment and imaging of disturbances in electrical currents of conductive subsurface materials, by measuring the electrical response at the ground's surface or in boreholes. It has an increasing number of applications, from mapping fluid flow in the subsurface of the Earth, to understanding the plumbing systems of geothermal fields, and detecting preferential flow paths in earth dams and embankments"--