Gravity-magnetic cross-gradient joint inversion by the cyclic gradient method |
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Authors: | Cong Sun |
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Affiliation: | School of Science, Beijing University of Posts and Telecommunications, Beijing, Peoples Republic of China https://orcid.org/0000-0002-5660-8280 |
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Abstract: | In this paper, we consider a joint-inversion problem using different types of geophysical data: gravity and magnetism. We first formulate two kinds of inverse problems in the famework of the first kind Fredholm integral equations, and then build up a sparse inversion model combining the two inverse problems as well as the cross-gradient term. The cyclic gradient method for quadratic function minimization is extended for solving the corresponding optimization problem. We update the stepsizes in a cyclic way, by combining the approximated Cauchy steps and the fixed steplengths. Theoretical analysis shows that the algorithm converges R-linearly. Experimental tests show that the proposed joint inversion sparse model as well as the proposed cyclic gradient method improve the numerical performances effectively, compared to the state of the art. |
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