Regional correction of gravity data

Summary Methods for the elimination of the regional effect from gravity data are discussed in this paper. A historical review of the average gradient method used in torsion balance data is given. The connection between the averaging, or grid method, used on the gravity meter data and the average gradient method is pointed out and a criticism of these methods is given. Due to the ambiguity of the interpretation of gravity data no unique determination of the regional effect is possible and no mechanical method for its removal can be found. The determination of a regional gravity effect is an interpretation problem and for this reason it is unavoidably the subject of geological consideration and of the personal judgement of the interpreter. The method of smoothing the isogams and gravity curves is also discussed. A few suggestions are made for breaking the gravity data into two components (regional and residual) by the analysis of the gravity data. Finally the application of the second derivative methods for the elimination of the regional effect is discussed.