DC resistivity surveys

Using the same colour scheme as the flow diagram above, Figure 2 shows how this conceptual framework applies for DC methods. The energy source is a pair of electrodes that inject a well-known current into the ground at known locations (Fig. 2a). The earth affects this energy because variations in the electrical conductivity of subsurface structures will bend the current flow lines (Fig. 2b). The measured signals or data (Fig. 2c) will involve measurements of voltage at the earth's surface or within boreholes. This type of data contains information about how charges become distributed at boundaries where electrical conductivity changes.