Decorrugation of Enhanced Magnetic Field Maps

A common processing step used in the interpretation of airborne magnetic data is the calculation of an apparent susceptibility map. Where the original total magnetic field map has been poorly levelled, the high spatial frequency amplification inherent in the filtering process used to calculate apparent susceptibilities introduces large amplitude effects attributable to these levelling errors. By separating the gridded data into a long wavelength and a residual grid, and by appropriate directional filtering of the long wavelength grid, the effects of levelling errors on apparent susceptibility maps can be much reduced. The disadvantages of distortion of isolated anomalies introduced by this process are usually outweighed by the advantages of an apparent susceptibility map free from major levelling effects.