TY - JOUR

T1 - Magnetic Anomalies Caused by 2D Polygonal Structures With Uniform Arbitrary Polarization

T2 - New Insights From Analytical/Numerical Comparison Among Available Algorithm Formulations

AU - Ghirotto, Alessandro

AU - Zunino, Andrea

AU - Armadillo, Egidio

AU - Mosegaard, Klaus

PY - 2021/4/16

Y1 - 2021/4/16

N2 - Since the '60s of the last century, the calculation of the magnetic anomalies caused by 2D uniformly polarized bodies with polygonal cross-section has been mainly performed using the popular algorithm of Talwani and Heirtzler (1962, 1964). Recently, Kravchinsky et al. (2019, https://doi.org/10.1029/2019GL082767) claimed errors in the above algorithm formulation, proposing new corrective formulas and questioning the effectiveness of almost 60 years of magnetic calculations. Here we show that the two approaches are equivalent and Kravchinsky et al.'s formulas simply represent an algebraic variant of those of Talwani and Heirtzler. Moreover, we analyze 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 and Bevis (1987, https://doi.org/10.1190/1.1442298). We release the source code of the algorithms in Julia and Python languages.

AB - Since the '60s of the last century, the calculation of the magnetic anomalies caused by 2D uniformly polarized bodies with polygonal cross-section has been mainly performed using the popular algorithm of Talwani and Heirtzler (1962, 1964). Recently, Kravchinsky et al. (2019, https://doi.org/10.1029/2019GL082767) claimed errors in the above algorithm formulation, proposing new corrective formulas and questioning the effectiveness of almost 60 years of magnetic calculations. Here we show that the two approaches are equivalent and Kravchinsky et al.'s formulas simply represent an algebraic variant of those of Talwani and Heirtzler. Moreover, we analyze 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 and Bevis (1987, https://doi.org/10.1190/1.1442298). We release the source code of the algorithms in Julia and Python languages.

KW - 2D forward modeling

KW - Computational geophysics

KW - Exploration geophysics

KW - Induced magnetization

KW - Magnetic anomaly

KW - Remnant magnetization

UR - http://www.scopus.com/inward/record.url?scp=85104294355&partnerID=8YFLogxK

U2 - 10.1029/2020GL091732

DO - 10.1029/2020GL091732

M3 - Letter

AN - SCOPUS:85104294355

VL - 48

JO - Geophysical Research Letters

JF - Geophysical Research Letters

SN - 0094-8276

IS - 7

M1 - e2020GL091732

ER -