A METHOD TO ESTIMATE THE TOTAL MAGNETIZATION DIRECTION FROM A DISTORTION ANALYSIS OF MAGNETIC-ANOMALIES

Knowledge of the declination and inclination of the total and induced magnetization vectors is normally required for the interpretation and analysis of magnetic anomalies. A new method of estimating the direction of the total magnetization vector of magnetized rocks from magnetic anomalies is proposed. The unknown declination and inclination (D(T)* and I(T)*) can be found by applying a reduction-to-the-pole operator to the measured anomalies for different couples of total magnetization direction parameters (DT and IT) and by observing the variation of the anomaly minimum as a function of both D(T) and I(T).I(T)* and D(T)* are estimated using the maximum of this function. Comparing our method to previous methods, one advantage is that our estimates are not zero-level dependent; furthermore, the method allows inclinations to be well estimated, with the same accuracy as declinations; finally declinations are not underestimated. Our method is applied to a real case and meaningful results are obtained; it is shown that the feasibility of the method is improved by removing the low-frequency components.