A Unified Method for Calculating the Depth to Source of Horizontal Density Layers

The depth, thickness and density contrast of semi-infinite horizontal layers can be automatically calculated using a set of four quantities derived from their gravity anomalies. The ratio α between the thickness and the depth to top is uniquely characterised by a combination of the curvatures of both the horizontal gradients of the anomalies and of their vertical gradient. The equation forms the basis for a new tool that builds on previous methods based on curvatures. While separate calculations were previously necessary for each end-member model, the proposed method gives an estimate of the type of source directly. In practice, when tested on the Bishop model, the method offers good performance for the quality of depth estimates and compares favourably with other methods. However, the accuracy of the calculated source properties can be affected by large errors. Interfering sources and data resolution are likely to be the main source of errors.