Stable Gravity Gradients In Frequency Domain

The analysis of gradients of the gravity field has been<br>a popular method of interpretation due to the fact that<br>gradients accentuate anomalies caused by shallow<br>sources at the expense of those from deeper sources.<br>Gradients can be either measured in the field or<br>directly calculated from a previously measured<br>gravity survey. However, calculated gradients are<br>usually noisy because the derivative operator<br>amplifies the high frequency content of the noise as<br>well as the signal. Therefore, it is necessary to reduce<br>the amount of noise in the calculated gradients.<br>Horizontal gradients XZ and YZ with reduced<br>amount of high frequency noise can be obtained in<br>the frequency domain by inverting the Fourier<br>transform of the gravity field with regularization.<br>Using the Hilbert transform relations between the<br>gradient components of the potential fields, all the<br>other gradients can be obtained without significant<br>changes in the noise level.