1887
Volume 13 Number 1
  • ISSN: 1569-4445
  • E-ISSN: 1873-0604

Abstract

ABSTRACT

Airborne time‐domain electromagnetic methods (AEM) are useful for hydrogeological mapping due to their rapid and extensive spatial coverage and high correlation between measured magnetic fields, electrical conductivity, and relevant hydrogeological parameters. However, AEM data, preprocessing and modelling procedures can suffer from inaccuracies that may dramatically affect the final interpretation. We demonstrate the importance and the benefits of advanced data processing for two AEM datasets (AeroTEM III and VTEM) collected over the Spiritwood buried valley aquifer in southern Manitoba, Canada. Early‐time data gates are identified as having significant flight‐dependent signal bias that reflects survey flights and flight lines. These data are removed from inversions along with late time data gates contaminated by apparently random noise. In conjunction with supporting information, the less‐extensive, but broader‐band VTEM data are used to construct an electrical reference model. The reference model is subsequently used to calibrate the AeroTEM dataset via forward modelling for coincident soundings. The procedure produces calibration factors that we apply to AeroTEM data over the entire survey domain. Inversion of the calibrated data results in improved data fits, particularly at early times, but some flight‐line artefacts remain. Residual striping between adjacent flights is corrected by including a mean empirical amplitude correction factor within the spatially constrained inversion scheme. Finally, the AeroTEM and VTEM data are combined in a joint inversion. Results confirm consistency between the two different AEM datasets and the recovered models. On the contrary, joint inversion of unprocessed or uncalibrated AEM datasets results in erroneous resistivity models which, in turn, can result in an inappropriate hydrogeological interpretation of the study area.

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2010-02-01
2024-03-28
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References

  1. AukenE., JørgensenF. and SørensenK.I.2003. Large‐scale TEM investigation for groundwater. Exploration Geophysics33, 188–194. doi: 10.1071/EG03188.
    [Google Scholar]
  2. AukenE., ChristiansenA.V., JacobsenL.H. and SørensenK.I.2008. A resolution study of buried valleys using laterally constrained inversion of TEM data. Journal of Applied Geophysics65, 10–20. doi:10.1016/j.jappgeo.2008.03.003.
    [Google Scholar]
  3. AukenE., ChristiansenA.V., WestergaardJ.H., KirkegaardC., FogedN. and ViezzoliA.2009. An integrated processing scheme for high‐resolution airborne electromagnetic surveys, the SkyTEM system. Exploration Geophysics40, 184–192. doi:10.1071/EG08128.
    [Google Scholar]
  4. BrodieR.S. and SambridgeM.2006. A holistic approach to inversion of frequency domain airborne EM data. Geophysics71, 301–312. doi: 10.1190/1.2356112.
    [Google Scholar]
  5. ChristiansenA.V., AukenE. and ViezzoliA.2011. Quantification of modeling errors in airborne TEM caused by inaccurate system description. Geophysics76, 43–52. doi: 10.1190/1.3511354.
    [Google Scholar]
  6. ChristiansenA.V., AukenE., FogedN. and S0rensenK.I.2007. Mutually and laterally constrained inversion of CVES and TEM data: a case study. Near Surface Geophysics5, 115–123. doi: 10.3997/18730604.2006023.
    [Google Scholar]
  7. CrowH.L., KnightR.D., MedioliB.E., HintonM.J., PlourdeA., PuginA.J.‐M.et al. 2012. Geological, hydrogeological, geophysical, and geochemistry data from a cored borehole in the Spiritwood buried valley, southwest Manitoba. Geological Survey of Canada, Open File 7079, doi:10.495/291486.
  8. DanielsenJ.E., AukenE., JorgensenF., SondergaardV. and SorensenK.I.2003. The application of the transient electromagnetic method in hydro‐geophysical surveys. Journal of Applied Geophysics53, 181–198.
    [Google Scholar]
  9. DavisA., MacnaeJ. and RobbT.2006. Pendulum motion in airborne HEM systems. Exploration Geophysics37, 355–362. doi: 10.1071/EG06355.
    [Google Scholar]
  10. GoldmanM., TabarovskyL. and RabinovichM.1994. On the influence of 3‐D structures in the interpretation of transient electromagnetic sounding data. Geophysics59, 889–901. doi: 10.1190/1.1443648.
    [Google Scholar]
  11. HuangH. and RuddJ.2008. Conductivity‐depth imaging of helicopter‐borne TEM data based on a pseudolayer half‐space model. Geophysics73, 115–120. doi: 10.1190/1.2904984.
    [Google Scholar]
  12. JørgensenF. and SandersenP.B.E.2006. Buried and open tunnel valleys in Denmark ‐ erosion beneath multiple ice sheets. Quaternary Science Reviews25, 1339–1363. doi:10.1016/j.quascirev.2005.11.006.
    [Google Scholar]
  13. JørgensenF. and SandersenP.B.E.2009. Buried Valley mapping in Denmark: evaluating mapping method constraints and the importance of data density. Zeitschrift der Deutschen Gesellschaft für Geowissenschaften160, 211–223. doi: 10.1127/1860‐1804/2009/01600211.
    [Google Scholar]
  14. JørgensenF., ScheerW., ThomsenS., SonnenborgT.O., HinsbyK., WiederholdH.et al. 2012. Transboundary geophysical mapping of geological elements and salinity distribution critical for the assessment of future sea water intrusion in response to sea level rise. Hydrology and Earth System Sciences16, 1845–1862. doi:10.5194/hess‐16‐1845‐2012.
    [Google Scholar]
  15. LegaultJ.M., PrikhodkoA., DoddsD.J., MacnaeJ.C. and Oldenborger, G.A.2012. Results of recent VTEM helicopter system development testing over the Spiritwood Valley aquifer, Manitoba. 25th SAGEEP 2012, Symposium on the Application of Geophysics to Engineering and Environmental Problems, Tucson, Arizona, USA, Expanded Abstracts.
    [Google Scholar]
  16. LinesL.R., SchultzA.K. and TreitelS.1988. Cooperative inversion of geophysical data. Geophysics53, 8–20. doi: 10.1190/1.1442403
    [Google Scholar]
  17. MacnaeJ.C., SmithR., PolzerB.D., LamontagneY. and KlinkertP.S.1991. Conductivity‐depth imaging of airborne electromagnetic step response data. Geophysics56, 102–114. doi: 10.1190/1.1442945.
    [Google Scholar]
  18. MacnaeJ.C. and Baron‐HayS.2010. Reprocessing strategy to obtain quantitative early‐time data from historic VTEM surveys. 21st International Geophysical Conference & Exhibition, ASEG, Sydney, Australia.
    [Google Scholar]
  19. MejuM.A.1996. Joint inversion of TEM and distorted MT soundings: Some effective practical considerations. Geophysics61, 56–65. doi:10.1190/1.1443956.
    [Google Scholar]
  20. MøllerI., SøndergaardV.H., JørgensenF., AukenE. and ChristiansenA.V.2009. Integrated management and utilization of hydrogeophysical data on a national scale. Near Surface Geophysics7, 647–659. doi:10.3997/1873‐0604.2009031
    [Google Scholar]
  21. OldenborgerG.A., PuginA.J.‐M. and PullanS.E.2013. Airborne timedomain electromagnetics, electrical resistivity and seismic reflection for regional three‐dimensional mapping and characterization of the Spiritwood Valley Aquifer, Manitoba, Canada. Near Surface Geophysics11, 63–74. doi: 10.3997/1873‐0604.2012023.
    [Google Scholar]
  22. PalackyG.J. and WestG.F.1991. Airborne electromagnetic methods. In: Electromagnetic Methods in Applied Geophysics, Vol. 2, (ed. M.N.Nabighian ), pp. 811–877, SEG Investigations in Geophysics.
    [Google Scholar]
  23. PodgorskiJ.E., AukenE., SchamperC., ChristiansenA.V., KalscheuerT. and GreenA.G.2013. Processing and inversion of commercial helicopter time‐domain electromagnetic data for environmental assessments and geologic and hydrologic mapping. Geophysics78, 149–159. doi:10.1190/GEO2012‐0452.1.
    [Google Scholar]
  24. PuginA.J.‐M., PullanS.E., HunterJ.A. and OldenborgerG.A.2009a. Hydrogeological prospecting using P and S‐wave landstreamer seismic reflection methods. Near Surface Geophysics7, 315–327. doi: 10.3997/1873‐0604.2009033.
    [Google Scholar]
  25. PuginA.J.‐M., OldenborgerG.A., CummingsD.I., RussellH.A.J. and SharpeD.R.2014. Architecture of buried valleys in glaciated Canadian Prairie regions based on high resolution geophysical data. Quaternary Science Reviews86, 13–23.
    [Google Scholar]
  26. PuginA.J.‐M., OldenborgerG.A. and PullanS.2011. Buried Valley imaging using 3‐C seismic reflection, electrical resistivity and AEM surveys. SAGEEP 2011, Charleston, South Carolina, USA. Extended Abstract.
    [Google Scholar]
  27. RaicheA.P., JuppD.L.B., RutterH. and VozoffK.1985. The joint use of coincident loop transient electromagnetic and Schlumberger sounding to resolve layered structures. Geophysics50, 1618–1627. doi:10.1190/1.1441851
    [Google Scholar]
  28. RainsfordD.2013. Personal Communication. Ontario Geological Survey, Ministry of Northern Development and Mines.
    [Google Scholar]
  29. SantosF.A.M. and El‐KalioubyH.M.2010. Comparative study of local versus global methods for 1D joint inversion of direct current resistivity and time‐domain electromagnetic data. Near Surface Geophysics8, 135–143. doi:10.3997/1873‐0604.2009056.
    [Google Scholar]
  30. SapiaV., OldenborgerG.A., ViezzoliA. and MarchettiM.2014. Incorporating ancillary data into the inversion of airborne timedomain electromagnetic data for hydrogeological applications. Journal of Applied Geophysics104, 35–43. doi: 10.1016/j.jappgeo.2014.02.009.
    [Google Scholar]
  31. SchmutzM., AlbouyY., GuérinR., MaquaireO., VassalJ., SchottJ.J.et al. 2000. Joint electrical and time domain electromagnetism (TDEM) data inversion applied to the Super Sauze earthflow (France). Surveys in Geophysics21, 371–390. doi: 10.1023/A:1006741024983.
    [Google Scholar]
  32. SiemonB., ChristiansenA.V. and AukenE.2009. A review of helicopter‐borne electromagnetic methods for groundwater exploration. Near Surface Geophysics7, 629–646. doi:10.3997/1873‐0604.2009043
    [Google Scholar]
  33. SorensenC., MundayT. and CahillK.2012. Different aem systems = different results... or should that necessarily be the case?SAGEEP 2012, Tucson, Arizona, USA.
    [Google Scholar]
  34. SteuerA., SiemonB. and AukenE.2009. A comparison of helicopter‐borne electromagnetic in frequency‐ and time‐domain at the Cuxhaven valley in Northern Germany. Journal of Applied Geophysics67, 194–205, doi: 10.1016/j.jappgeo.2007.07.001.
    [Google Scholar]
  35. ViezzoliA., ChristiansenA.V., AukenE. and SørensenK.2008. Quasi‐3D modeling of airborne TEM data by spatially constrained inversion. Geophysics73, 105–113. doi: 10.1190/1.2895521.
    [Google Scholar]
  36. VozoffK. and JuppD.L.B.1975. Joint inversion of geophysical data. Geophysical Journal of the Royal Astronomical Society42, 977–991. doi: 10.1111/j.1365‐246X.1975.tb06462.x.
    [Google Scholar]
  37. WinterT.C., BensonR.D., EngbergR.A., WicheG.J., EmersonD.G., CrosbyO.A. and MillerJ.E.1984. Synopsis of ground‐water and surface‐water resources of North Dakota. United States Geological Survey, Open File Report84–732.
    [Google Scholar]
  38. WisénR. and ChristiansenA.V.2005. Laterally and mutually constrained inversion of surface wave seismic data and resistivity data. Journal of Environmental & Engineering Geophysics10, 251–262. doi: 10.2113/JEEG10.3.251.
    [Google Scholar]
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