Abstract
This research deals with the essential steps carried out during the processing and inversion of the airborne time-domain electromagnetic (TEM) data used within the framework of the GhanAqua project – aiming at the groundwater development for sustainable agriculture in the White Volta basin in Ghana.
The processing of pre-existing airborne TEM data has been performed with the state-of-the-art methodologies. In this respect, (1) the minimum possible gate-dependent lateral stacking between adjacent soundings has been performed for the preparation of the data; (2) a 1D nonlinear forward modelling has been used for the inversion of the stacked data; (3) even if the forward modelling was 1D, the data have been inverted by spatially constraining the adjacent models (in a pseudo-2/3D fashion). We adopted an iterative approach in which the processing and inversion parameters, and the type of stabilizer utilized, have been decided after an a-posteriori analysis. Hence, after every inversion, the results have been discussed with the geologists (1) to assess, at least qualitatively, the uncertainty of the solution features and (2) to, as much as possible, include prior geological knowledge into the geophysical analysis.
The new geophysical insights detected geological features that might be interpreted as glacial paleovalleys. If confirmed, those structures can have a significant impact in terms of their socio-economic relevance (i.e. as groundwater reservoirs); as well as from a scientific point of view (as they would require rethinking the stratigraphy of the area). In addition, these kind of Sturtian glacial evidences in West Africa could support the Snowball Earth hypothesis.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Fugro airborne surveys: Airborne geophysical survey of the Volta River Basin and Keta Basin logistics and processing report Geotem areas 1 to 8. Job. N. 06401 (2008)
Fugro airborne surveys: Airborne geophysical survey of the Volta River Basin and Keta Basin logistics and processing report Geotem regional survey. Job. N. 06401 (2008)
Macnae, J.C., Smith, R., Polzer, B.D., Lamontagne, Y., Klinkert, P.S.: Conductivity-depth imaging of airborne electromagnetic step-response data. Geophysics 56, 102–114 (1991)
Christiansen, A.V., Auken, E., Kirkegaard, C., Schamper, C., Vignoli, G.: An efficient hybrid scheme for fast and accurate inversion of airborne transient electromagnetic data. Explor. Geophys. 47(4), 323–330 (2016)
Smith, R., Annan, P.: The use of B-field measurements in airborne time-domain system: Part I. benefits of B-field versus dB/dt data. Explor. Geophys. 29, 24–29 (1998)
Auken, E., et al.: An overview of a highly versatile forward and stable inverse algorithm for airborne, groundbased and borehole electromagnetic and electric data. Explor. Geophys. 46(3), 223–235 (2015). https://doi.org/10.1071/eg13097
Wilson, G.A., Raiche, A., Sugeng, F.: 2.5D inversion of airborne electromagnetic data. Explor. Geophys. 37, 363–371 (2006)
Cox, L.H., Wilson, G.A., Zhdanov, M.S.: 3D inversion of airborne electromagnetic data using a moving footprint. Explor. Geophys. 41, 250–259 (2013)
Ley-Cooper, A.Y., et al.: Airborne electromagnetic modelling options and their consequences in target definition. Explor. Geophys. 46, 74–84 (2014). https://doi.org/10.1071/eg14045
Auken, E., Christiansen, A.V., Westergaard, J.H., Kirkegaard, C., Foged, N., Viezzoli, A.: An integrated processing scheme for high-resolution airborne electromagnetic surveys, the SkyTEM system. Explor. Geophys. 40, 184–192 (2009)
Vignoli, G., Gervasio, I., Brancatelli, G., Boaga, J., Della Vedova, B., Cassiani, G.: Frequency-dependent multi-offset phase analysis of surface waves: an example of high-resolution characterization of a riparian aquifer. Geophys. Pros. 64, 102–111 (2015)
Viezzoli, A., Munday, T., Auken, E., Christiansen, A.V.: Accurate quasi 3D versus practical full 3D inversion of AEM data – the Bookpurnong case study. Preview 149, 23–31 (2010). https://doi.org/10.1071/PVv2010n149p23
Commer, M., Hordt, A., Helwig, S., Scholl, C.: Threedimensional inversion of time-domain EM data with highly constrained model complexities. In: 20 Kolloquium Elektromagnetische Tiefenforschung, pp. 114–123 (2003)
Zhdanov, M.S., Vignoli, G., Ueda, T.: Sharp boundary inversion in crosswell travel-time tomography. J. Geophys. Eng. 3(2), 122–134 (2006)
Ley-Cooper, A.Y., et al.: Airborne electromagnetic modelling options and their consequences in target definition. Explor. Geophys. 46(1), 74–84 (2015)
Vignoli, G., Sapia, V., Menghini, A., Viezzoli, A.: Examples of improved inversion of different airborne electromagnetic datasets via sharp regularization. J. Environ. Eng. Geophys. 22(1), 51–61 (2017)
Pagliara, G., Vignoli, G.: Focusing inversion techniques applied to electrical resistance tomography in an experimental tank. In: XI International Congress of the International Association for Mathematical Geology, Liège, Belgium (2006)
Vignoli, G., Zanzi, L.: Focusing inversion technique applied to radar tomographic data. In: Near Surface – 11th European Meeting of Environmental and Engineering Geophysics, European Association of Geoscientists & Engineers, Palermo (2005)
Vignoli, G., Deiana, R., Cassiani, G.: Focused inversion of vertical radar profile (VRP) traveltime data. Geophysics 77(1), H9–H18 (2012)
Dzikunoo, E.A., Vignoli, G., Jørgensen, F., Yidana, S.M., Banoeng-Yakubo, B.: New regional stratigraphic insights from a 3D geological model of the Nasia sub-basin, Ghana, developed for hydrogeological purposes and based on reprocessed B-field data originally collected for mineral exploration. Solid Earth 11, 349–361 (2020)
Utsugi, M.: 3-D inversion of magnetic data based on the L1–L2 norm regularization. Earth Planets Space 71(1), 1–19 (2019). https://doi.org/10.1186/s40623-019-1052-4
Vignoli, G., Fiandaca, G., Christiansen, A.V., Kirkegaard, C., Auken, E.: Sharp spatially constrained inversion with applications to transient electromagnetic data. Geophys. Prospect. 63(1), 243–255 (2015). https://doi.org/10.1111/1365-2478.12185
Tarantola, A.: Popper, Bayes and the inverse problem. Nat. Phys. 2, 492 (2006). https://doi.org/10.1038/nphys375
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2020 Springer Nature Switzerland AG
About this paper
Cite this paper
Vignoli, G., Dzikunoo, E.A., Jørgensen, F., Yidana, S.M., Banoeng-Yakubo, B., Bai, P. (2020). Geophysical Modelling of a Sedimentary Portion of the White Volta Basin (Ghana). In: Gervasi, O., et al. Computational Science and Its Applications – ICCSA 2020. ICCSA 2020. Lecture Notes in Computer Science(), vol 12255. Springer, Cham. https://doi.org/10.1007/978-3-030-58820-5_64
Download citation
DOI: https://doi.org/10.1007/978-3-030-58820-5_64
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-030-58819-9
Online ISBN: 978-3-030-58820-5
eBook Packages: Computer ScienceComputer Science (R0)