A LEAST-SQUARES APPROACH TO SHAPE DETERMINATION FROM RESIDUAL SELF-POTENTIAL ANOMALIES

We have developed a least-squares minimization approach to determine t he shape (shape-factor) of a buried polarized body from a residual sel f-potential anomaly profile. By defining the zero anomaly distance and the anomaly value at the origin on the profile, the problem of the sh ape-factor determination is transformed into the problem of finding a solution of a nonlinear equation of the form f(q) = 0. Procedures are also formulated to estimate the depth of polarization angle, and the e lectric dipole moment. The method is applied to synthetic data with an d without random noise. The obtained shape-factor agrees very well wit h the model shape-factor when using synthetic data. After adding +/-2 percent random error in the synthetic data, the shape factor obtained is within +/-4 percent. Finally the validity of the method is tested o n a field example from the Ergani copper district, Turkey.