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Magnetic anomalies caused by 2D polygonal structures with uniform arbitrary polarization: new insights from analytical/numerical comparison among available algorithm formulations
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  • Alessandro Ghirotto,
  • Andrea Zunino,
  • Egidio Armadillo,
  • Klaus Mosegaard
Alessandro Ghirotto
DISTAV, Applied Geophysics Laboratory, University of Genova

Corresponding Author:[email protected]

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Andrea Zunino
Niels Bohr Institute, University of Copenhagen, now at the Institute of Geophysics, ETH Zürich
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Egidio Armadillo
DISTAV, Applied Geophysics Laboratory, University of Genova
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Klaus Mosegaard
Niels Bohr Institute, University of Copenhagen
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Abstract

Since the ’60s of the last century, the calculation of the magnetic anomaly caused by 2D uniformly-polarized bodies with polygonal cross-section was mainly performed using the popular algorithm of Talwani & Heirtzler (1962, 1964). Recently, Kravchinsky et al. (2019) claimed errors in the above algorithm formulation, proposing new corrective formulas and questioning the effectiveness of almost sixty years of magnetic calculations. Here we showed, demonstrating analytical equivalence of the two approaches, that Kravchinsky et al.’s formulas simply represent an algebraic variant of those of Talwani & Heirtzler. Moreover, we performed intensive numerical analysis generating a large amount of random magnetic scenarios, involving both changing-shape polygons and a realistic geological model, showing a complete agreement among the magnetic responses of the two discussed algorithms and the one proposed by Won & Bevis (1987). Additionally, we released the source code of the algorithms in Julia and Python languages.