Spatially constrained inversion for quasi 3-D modelling of AEM data

Abstract

The spatially constrained inversion (SCI) produces quasi-3D modelling of geoelectrical and EM data of varying spatial density, using a 1D forward solution. Information migrate horizontally through spatial constraints and allow resolution of layers that would be locally poorly resolved. The constraints are built using the Delaunay triangulation, which ensures automatic adaptation to data density variations. It also allows creation of subsets suitable for parallel computing. In this study the SCI was applied to airborne time domain EM soundings (SkyTEM data from the Island of Lolland, Denmark), but it can be implemented also with all other data types. The field case study proves that the SCI produces laterally c onsistent results that respect the 3D geological variations of the sedimentary settings. The resolution of near surface tills and water bearing sand and gravel layers is greatly enhanced and so is the boarder of the saline groundwater intrusion beneath the island. The SCI also suppresses the elongated artifacts commonly seen in profile oriented data sets.