Geophysical Prospecting, 2014, 62, 1162–1168 doi: 10.1111/1365-2478.12119 Avoidable Euler Errors – the use and abuse of Euler deconvolution applied to potential fields * Alan B. Reid 1,2 † ,J¨ org Ebbing 3,4 and Susan J. Webb 5 1 Reid Geophysics Ltd, Eastbourne, UK., 2 School of Earth and Environment, University of Leeds, Leeds, UK, 3 Geological Survey of Norway (NGU), Trondheim, Norway, 4 Department of Petroleum Engineering and Applied Geophysics, Norwegian University of Science and Technology (NTNU), Trondheim, Norway, and 5 School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa Received April 2013, revision accepted December 2013 ABSTRACT Window-based Euler deconvolution is commonly applied to magnetic and sometimes to gravity interpretation problems. For the deconvolution to be geologically mean- ingful, care must be taken to choose parameters properly. The following proposed process design rules are based partly on mathematical analysis and partly on experi- ence. 1. The interpretation problem must be expressible in terms of simple structures with integer Structural Index (SI) and appropriate to the expected geology and geophysical source. 2. The field must be sampled adequately, with no significant aliasing. 3. The grid interval must fit the data and the problem, neither meaninglessly over- gridded nor so sparsely gridded as to misrepresent relevant detail. 4. The required gradient data (measured or calculated) must be valid, with sufficiently low noise, adequate representation of necessary wavelengths and no edge-related ringing. 5. The deconvolution window size must be at least twice the original data spacing (line spacing or observed grid spacing) and more than half the desired depth of investigation. 6. The ubiquitous sprays of spurious solutions must be reduced or eliminated by judicious use of clustering and reliability criteria, or else recognized and ignored during interpretation. 7. The process should be carried out using Cartesian coordinates if the software is a Cartesian implementation of the Euler deconvolution algorithm (most accessible implementations are Cartesian). If these rules are not adhered to, the process is likely to yield grossly misleading results. An example from southern Africa demonstrates the effects of poor parameter choices. Key words: Gravity, Interpretation, Magnetics, Potential Fields, Euler Deconvolu- tion. ∗ Presented at 74th EAGE meeting, Copenhagen, Denmark † E-mail: alan@reid-geophys.co.uk INTRODUCTION The interpretive technique commonly known as Euler Decon- volution was first proposed in a workable form applied to magnetic profile data by Thompson (1982). Reid et al. (1990) 1162 C  2014 European Association of Geoscientists & Engineers