Geological Modelling Implications - Different Inversion Strategies from AEM Data

A. Rapiti;F. Jørgensen;A. Menghini;A. Viezzoli;G. Vignoli

2018-01-01

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Abstract

Data from AEM survey, carried out in the Peace Region of NE British Columbia to support groundwater investigation, were used in this study. An understanding of the geological structures can have significant implication in groundwater management decisions. Previous studies have demonstrated the presence of shallow aquifers specifically those within paleovalleys. In this study we present different inversion strategies and their geological modelling implications. The aim was to obtain geophysical models that have better resolved electrical resistivity units. This, therefore, should allow more straightforward geological interpretation. Different types of geophysical inversions on synthetic data have been performed. Testing different settings, for each inversion strategy permitted to study how the final geophysical model could change. This workflow was applied to real data over a subset collected in the south-western part of the Peace Region, an area characterized by different buried valleys. Sharp Laterally Constrained inversions have been thoroughly investigated. The sharp result is very sensitive to settings choice: sharp inversion with tight settings allows to recognition of the basic electrical resistivity blocks of the model, on the other hand, sharp-inversion with loose settings allows to obtain resistivity variations within the blocks. We present a rough geological interpretation on a representative cross section.