Interpretation of self-potential anomalies by Enhanced Local Wave number technique

A model-independent technique, based on the Enhanced Local Wave number (Kx, Kz), has been discussed to interpret self-potential anomalies over a pole, a horizontal line of poles, a horizontal cylinder, a sphere and an inclined sheet. The present method involves computation of second order derivatives with respect to Cartesian coordinate system. An equation, which is independent of the source geometry, has been used to compute the unknown source parameters. A procedure has been discussed to suppress the high frequency noises present in the observations to achieve derivatives of the signal with reasonably correct amplitude and low noise content. A study on the reliability and the applicability of the technique reveals that for accurate determination of depth and structural index (SI) of a source, the ratio of depth to data spacing should be 5 and above. Further, SI computation from Kx is more reliable than that by Kz. A random error of 10% in simulated anomalies has no significant effect on the computed model parameters except for a horizontal line of poles. The applicability of the proposed technique has been demonstrated through four field examples, with different levels of complexities, adopted from published literature.