IP is commonly conducted in conjunction with ERT by measuring how the induced voltage decays with time. The measurement is based on how long the subsurface materials hold a charge, once the voltage has been removed, this is termed the materials ‘chargeability’. The IP method is one of the most common field techniques for shallow- and deep-mineral exploration. Only recently has its use been exploited in engineering, environmental and groundwater geophysics. A high IP response can indicate isolated high moisture zones, pockets or lenses of mineralogical clay, or ore bodies. It has proved useful for environmental geophysics to supplement ERT results routinely used to map undocumented landfills, the IP is particularly useful for determining the landfill thickness or vertical extent. The IP-effect is a complex measurement, and requires significantly more experience to use and interpret than most geophysical techniques.
Applicable On: Soil, Rock, Landfill Materials, and Groundwater.
Test For: Saturated zones, aquatards, mineral/ore bodies, landfill delineation (thickness).