Depth determination of 2-D SP anomaly source using Energy Spectrum method and its advantages

Self potential (SP) method is a passive method that involves measurements of naturally occurring potentials, commonly associated with the weathering of sulfides ore bodies. Energy spectrum (power spectrum) method developed primarily for gravity and magnetic data have been adapted to electrical SP data. In case of SP data analysis, energy is taken as the square of the Fourier amplitude spectrum which is directly proportional to the exponential of the depth of the causative source. From the energy spectrum, depth to the causative source can be estimated as half of the slope of the straight line of the spectrum. The spectrum method appears to have certain advantage over other methods like Euler and Tilt angle methods in the sense that it also gives the vertical extent of the causative ore body.