Applications Of The Self-Potential Method For Engineering And Environmental Investigations

Self-potential (SP) surveys detect surface voltage variations<br>caused by subsurface flows of fluid, heat, and ions. Therefore<br>the SP method can be useful in applications where such flows are<br>related to subsurface targets of engineering or environmental<br>interest. Examples of engineering and environmental applications<br>of the SP method discussed in this paper include studies of fluid<br>flow in the vicinity of dams, reservoirs, wells, and faults;<br>investigations of coal mine fires, steam injection, and nuclear<br>tests; and surveys for environmental contaminants.<br>Although the equipment and field procedures used for SP<br>surveys are relatively simple, considerable care must be taken to<br>ensure that data are reproducible, that sources of noise are<br>recognized, and that appropriate data reduction techniques are<br>used to correct for electrode drift and polarization.<br>Interpretation of SP data then may be carried out using<br>qualitative, geometric, or analytic methods. Qualitative<br>recognition of typical anomaly patterns is helpful for<br>determining source locations and selection of more quantitative<br>interpretation methods. Geometric source modeling, similar to<br>that done for other potential field methods such as gravity and<br>magnetics, is used to estimate source configuration and depth.<br>Analytical modeling, based on concepts of irreversible<br>thermodynamics and coupled flows, can provide information about<br>the nature, location, and intensity of SP anomaly sources.