Analysis of gravity gradients over a thin infinite sheet

Expressions are derived for the horizontal and vertical gradients of the gravity anomaly over a thin dipping sheet of infinite depth extent. The resultant of these two gradients, known as the complex gradient, is also derived and properties of the amplitude and phase responses of the complex gradient are studied. It is shown that the amplitude plot is a symmetric curve whose, shape is independent of the dip (?) of the sheet whereas the phase plot is an antisymmetric curve with an offset value equal to ?-π/2. The depth to top of the sheet is obtained from the amplitude plot. The method is applied on a field example and the results are in good agreement with the results obtained by earlier workers.