Analysis and interpretation of magnetic anomalies based on the analytic signal amplitudes

The analytic signals are essentially a kind of all-pass filters. Since not suffering from the disturbation by human factors, they may perfectly reflect the information of the original signals. The analytic signal amplitude method is not only an effective method to analyze non-stationary signals, but also a powerful tool to detect the local characteristics of signals. In this paper, the complex signals are received from the real signals by the analytic signals, and the spatial distribution of the signal energy can be depicted from the amplitudes (spectrum) of the complex signals. Model tests indicate that the analytic signal amplitude method may reduce the false anomalies in some low degree of exploration regions, and cause the central locations of the underground magnetic bodyies and spectrums to be identical. This method is especially of more advantages in low-latitude or highly dissected areas. With the aid of this method in the measurement of magnetic anomalies of an iron ore district in Palishan, Laos, we delineated the distribution of the underground magnetite orebodies, and the reliability of the results has been proved by the data from 56 boreholes there.