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May 2022
AARMS Geophysical Inverse Problems Discussion Series
Zhang et al., 2022, Geophysical inversions on unstructured meshes using non-gradient based regularization The paper above, the main one we will discuss, seeks to improve upon the method in the paper below, which increases some computational demands. We'd like to better understand how well the paper above improves upon: Lelievre et al., 2013, Gradient and smoothness regularization operators for geophysical inversion on unstructured meshes.
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Farquharson, 2008, Constructing piecewise-constant models in multidimensional minimum-structure inversions. Also available on the author's webpage: https://www.esd.mun.ca/~farq/special.html Considering the discussion at our previous meeting, it seems natural to next look at methods for recovering sharp/blocky/compact features. This one is a relatively short paper, going back to a time when most inversion work was on rectilinear meshes, and it would be sensible to return to these ideas now that unstructured meshes are seeing more use.
Find out more »June 2022
AARMS Geophysical Inverse Problems Discussion
Gündoğdu & Candansayar, 2018, Three-dimensional regularized inversion of DC resistivity data with different stabilizing functionals. Also available on the author's ResearchGate page: https://www.researchgate.net/publication/326068036_Three-dimensional_regularized_inversion_of_DC_resistivity_data_with_different_stabilizing_functionals This paper compares several regularization functionals that have appeared in geophysical inversion literature. It can provide an overview for us before perhaps looking at some others in more detail, if needed. Friday, June 10, 2022 @ 1:30 pm – 2:30 pm (Atlantic time)
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Farquharson & Oldenburg, 2004, A comparison of automatic techniques for estimating the regularization parameter in non-linear inverse problems. Also available here: https://gif.eos.ubc.ca/sites/default/files/Farquharson_regparam_04.pdf This paper compares some common approaches for choosing the value of the regularization parameter in underdetermined, minimum-structure-type inverse problems. It can provide an overview for us before looking at more recent ideas. Friday, June 24, 2022 @ 1:30 pm – 2:30 pm (Atlantic time)
Find out more »July 2022
AARMS Geophysical Inverse Problems Discussion
Friday, July 15, 2022 @ 1:30 pm – 2:30 pm (Atlantic time) Bijani et al., 2017, Physical-property-, lithology- and surface-geometry-based joint inversion using Pareto Multi-Objective Global Optimization. If you are unable to access the paper through that link, please email the organizer (and co-author on the paper) for a copy (plelievre@mta.ca). This paper introduces the concept of multi-objective optimization and Pareto-optimality. In this work, instead of attempting to select a single value for the regularization parameter, the methods sample the entire…
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Lelièvre et al., 2012, Joint inversion of seismic traveltimes and gravity data on unstructured grids with application to mineral exploration. https://library.seg.org/doi/10.1190/geo2011-0154.1 If you are unable to access the paper through that link, please email the organizer (and co-author on the paper) for a copy (plelievre@mta.ca). This paper looks at various different methods to enforce the similarity of the different models in a joint inversion. This paper will help us discuss previous themes in relation to joint inversion, including the deterioration of…
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