Abstract
In this paper, we have developed a least-squares analysis method to estimate not only the depth and shape but also to determine the horizontal position of a buried structure from the residual SP anomaly profile. The method is based on normalizing the residual SP anomaly using three characteristic points and their corresponding distances on the anomaly profile and then determining the depth for each horizontal position of the buried structure using the least-squares method. The computed depths are plotted against the assumed horizontal positions on a graph. The solution for the depth and the horizontal position of the buried structure is read at the common intersection of the curves. Knowing the depth and the horizontal position and applying the least-squares method, the shape factor is determined using a simple linear equation. Procedures are also formulated to estimate the polarization angle and the electric dipole moment. The method is semi-automatic and it can be applied to short or long residual SP anomaly profiles. The method is applied to synthetic data with and without random noise. The validity of the method is tested on a field example from Turkey. In all cases, the model parameters obtained are in good agreement with the actual ones.