Electrical imaging of impact structures.
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Data
2012
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Resumo
Electrical imaging provides important subsurface information for the construction
of hypervelocity impact models. We here provide an overview and evaluation of
the current electrical imaging methods used in impact cratering studies. Although apparent
resistivity models are commonly used in the geoelectrical imaging of impact structures, the
reliability of these models has not hitherto been determined. In order to assess these
imaging approaches in impact cratering, we investigate for the first time the discrepancies
between the apparent resistivity and true resistivity models of an impact structure. To this
end, we present (1) a new true resistivity model of the Araguainha impact structure in
central Brazil by applying L2-norm inversion to previously published data, (2) apparent
resistivity model of the impact structure, and (3) models obtained from different stages of
the iterative tomographic inversions. Our results show that changes in vertical resistivity
gradient are significantly better defined in the true resistivity models than in the apparent
resistivity model. On the basis of these results, we outline a new approach that true
resistivity models can be effectively assessed by applying both L1- and L2-norm inversion
schemes together with the monitoring of intermediate models from iterative inversion. The
results of our study highlight the importance of tomographic inversion of resistivity data in
impact cratering studies, and they provide a data modeling framework and foundation for
cost-effective subsurface imaging of impact structures in the future.
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Palavras-chave
Resistivity, Impact crater, Geophysical inversion, Araguainha
Citação
TONG, C. H. et al. Electrical imaging of impact structures. Surveys in Geophysics, v. 33, p. 861–868, 2012. Disponível em: <https://link.springer.com/article/10.1007/s10712-012-9178-y>. Acesso em: 20 de jun. 2017.