Parametric inversion of residual magnetic anomalies due to simple geometric bodies

We have developed a simple method to determine the depth, inclination parameter and amplitude coefficient of a buried structure from a residual magnetic anomaly profile using a new formula representing the magnetic anomaly expressions produced by most geological structures. The method is based on defining the anomaly value at the origin and four characteristic points and their corresponding distances on the anomaly profile. Using all possible combinations of the four characteristic points and their corresponding distances, a procedure is developed for automated determination of the best fit model parameters including the shape (shape factor) of the buried structure from magnetic data. The method was applied to synthetic data with and without random errors and tested on two field examples from Canada and India. In both cases, the model parameters obtained by the present method, particularly the shape and depth of the buried structures, were found to be in good agreement with the actual parameters. The present method has the capability of avoiding highly noisy data points and enforcing the incorporation of points of the least random errors to enhance the interpretation results.