An alternative 3D inversion method for magnetic anomalies with depth resolution

A. Pignatelli, I. Nicolosi, M. Chiappini

Abstract


This paper presents a new method to invert magnetic anomaly data in a variety of non-complex contexts when
a priori information about the sources is not available. The region containing magnetic sources is discretized into
a set of homogeneously magnetized rectangular prisms, polarized along a common direction. The magnetization
distribution is calculated by solving an underdetermined linear system, and is accomplished through the simultaneous
minimization of the norm of the solution and the misfit between the observed and the calculated
field. Our algorithm makes use of a dipolar approximation to compute the magnetic field of the rectangular
blocks. We show how this approximation, in conjunction with other correction factors, presents numerous advantages
in terms of computing speed and depth resolution, and does not affect significantly the success of the
inversion. The algorithm is tested on both synthetic and real magnetic datasets.

Keywords


inversion;magnetic field;weighting function;dipolar approximation;depth resolution

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References


DOI: https://doi.org/10.4401/ag-3114

Published by INGV, Istituto Nazionale di Geofisica e Vulcanologia - ISSN: 2037-416X