CMD Mini Explorer unit by GF Instruments designed for multi-depth measurements. CMD Mini Explorer is used for the assessment of ground conductivity and of in-phase (susceptibility) using three dipole center distances (0.2m, 1.71m, 1.18m) in a frequency of 30 KHz, thus having a variable effective High/Low depth range (0.5/0.25m, 1.0/1.5m, 1.8/0.9m). The data are logged in a designated control unit either in manual or continuous mode with the extra option to also use a GPS unit for positioning.
EM surveys are especially adapted to mapping lateral differences of resistivity or conductivity. Possible geological targets are steep dipping structures, such as faults, fracture zones. Measurements of the quadrature mode permit an estimate of the soil conductivity, whereas measurements of the in-phase mode are proportional to the magnetic susceptibility of the soil.