SOME NOTES CONCERNING THE FREQUENCY ANALYSIS FOR GRAVITY INTERPRETATION*

One of the most important problems in the interpretation of gravity data is the separation of the data giving information characterizing the different geological structures. Various methods were elaborated to perform this separation (smoothing, removing of residuals, second derivatives, analytic continuation and others). For each operation various sets of coefficients were proposed. All these sets of coefficients may be considered as to provide linear filtering processes applied to the original map. The frequency response of the filter unambigously determines the method and gives good and clear information concerning their advantages (or disadvantages). The knowledge of frequency responses enables the choice of the most suitable method for the interpretation of a given map. Graphs are presented by the author showing:

• a.  the effect of radius used in the calculation of residuals
• b.  effect of the number of points used in averaging the data on a circle
• c.  the effect of the different systems of coefficients used in the various second derivative formulas.