Technical Papers - Airborne Magnetics

Estimating Depth and Model Type Using the Continuous Wavelet Transform of Magnetic Data

Marc A. Vallée, Fugro Airborne Surveys, Montreal
Pierre Keating, Geological Survey of Canada,
Richard S. Smith, and Camille St-Hilaire, Fugro Airborne Surveys.

Abstract

The continuous wavelet transform has been proposed recently for the interpretation of potential field anomalies. Using Poisson wavelets, which are equivalent to an upward continuation of the analytic signal, this technique allows one to estimate the depth of burial of homogeneous field sources and to determine the nature of the source in the form of a structural index. Moreau et al. (1999) accomplish this by successively testing the leastsquares misfit on a log-log plot of the wavelet transform amplitude versus the sum of the depth and the dilation (upward continuation height). We extend this methodology by analyzing the ratio of the Poisson wavelet coefficients of the first and second orders. For simple pole sources, this ratio at one dilation is enough to estimate the depth and index uniquely; but for extended sources of finite size, we must analyze the variation of the estimates with dilations. The technique gives good results on synthetic and field examples.

GEOPHYSICS, VOL. 69, NO. 1 (JANUARY-FEBRUARY 2004); P. 191-199, 15 FIGS. Published on Geophysics Online September 18, 2003. Presented at the 72nd Annual Meeting, Society of Exploration Geophysicists. Manuscript received by the Editor March 21, 2003; revised manuscript received August 19, 2003.   © 2004 Society of Exploration Geophysicists. All rights reserved.

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