The removal of unwanted edge contours from gravity datasetsGordon R. J. Cooper
School of Geosciences, University of the Witwatersrand, Johannesburg 2050, South Africa. Email: Gordon.Cooper@wits.ac.za
Exploration Geophysics 44(1) 42-47 https://doi.org/10.1071/EG12027
Submitted: 10 May 2012 Accepted: 12 September 2012 Published: 16 October 2012
Gravity data is widely used in the search for mineral deposits, and can be collected using ground, borehole, airborne, shipborne and satellite platforms. The boundaries between rocks with differing densities result in boundaries in their corresponding gravity anomalies. These boundaries, or edges, can be located using techniques based on horizontal derivatives of the data. Edge contours that do not relate to the current interpretation project can be considered as noise, and high resolution data can possess a proliferation of such edges, making interpretation difficult. While smoothing can be applied to reduce the number of edges, it has the disadvantage that the remaining edge locations are shifted and the shape of the edge contours is altered. Three methods are discussed here for the removal of unwanted edge contours. The first method removes edges which are not present in the data after its upward continuation to a user-selected height. The second method removes edges whose amplitude is below a given threshold, and the final method removes the smallest edge contours.
Key words: potential fields, semi-automatic interpretation methods.
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