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Depth estimation of total magnetic anomalies using Hilbert transform with 3-D analytic signal application, case study: iron ore Kheirabad, Sirjan, Iran

Document Type : Original Research Paper

Authors

1 Islamic Azad University, Science and Research Branch, Tehran

2 Department of Geophysics, Science and Research Branch, Islamic Azad University

3 Institute of Geophysics, University of Tehran, Department of Earth Physics

4 Department of Geophysics, Razi University

Abstract

An important goal in mining exploration is  the estimation of the depth and the thickness of the causative source. According to this simplification, several methods have been developed for interpreting magnetic field anomalies. In this article, the Hilbert transform has been used to calculate the depth and thickness of 3-D thin plate anomalies. The Hilbert-Fourier transform performs an important role in analytic signals. Since the total magnetic fields anomalies function has the characteristics necessary for an analytic function, i.e. its real and imaginary parts form a Hilbert transform pair, the function can be used to interpret networked data in terms of three-dimensional origins. The Hilbert transform does not change the amplitude of a function but shifts the phase by  and  for positive and negative phase values, respectively. This paper uses a two-dimensional Hilbert transform and a 3-D analytic function to calculate the depth of a thin three-dimensional plate modeled based on the method of Talwani for noisy data and without noise data. The results show that the estimated depth values derived from the Hilbert transform method are associated with an error of less that 3% for data without noise, and an error of 8% for data of 15% noise. . This method was also tested on the real magnetic anomaly data from the Kheirabad iron mine located at 5 km NE of Golgohar, Sirjan, Iran. The results were compatible with the Euler method and with drilling information of the mine. The obtained depth is in good agreement with the actual depth, which confirms the application of the Hilbert transform for the interpretation of field data and estimation of magnetic anomalies depths.

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References
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Scientific Quarterly Journal of Geosciences
Volume 27, Issue 108
September 2018
Pages 145-154
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