1887
Volume 5 Number 3
  • ISSN: 1569-4445
  • E-ISSN: 1873-0604

Abstract

The effect of a dipping layer on the first‐arrival traveltime from single‐offset profiling with borehole radar is investigated, including both zero‐offset and fixed‐offset profiling. In our study, offset refers to the vertical distance between bistatic radar antennae. Using forward modelling of electromagnetic wave travel, the traveltime of zero‐offset and fixed‐offset profiles through a dipping layer is compared to those of flat‐lying layers. The model considers three distinct raypaths: direct, critically refracted and cross‐dip refracted. Whereas critical refraction only occurs in a layer of low propagation velocity relative to an adjacent high‐velocity layer, cross‐dip refraction can occur in any velocity structure. The forward model demonstrated that the slope of the traveltime through the cross‐dip portion of the profile is approximately half of that in the critically refracted portion. To obtain the electromagnetic wave propagation velocities above and below the dip, only one profile is necessary. However, to invert for the dip angle and position, two profiles with different offsets must be considered together.

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2018-12-18
2020-04-01
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References

  1. AlumbaughD.L., ChangP.U., PaprockiL., BrainardJ., GlassR.J. and RautmanC.A.2002. Estimating moisture contents in the vadose zone using cross‐borehole ground penetrating radar: A study of accuracy and repeatability. Water Resources Research38, 1309.
    [Google Scholar]
  2. ASTM
    ASTM1992. Test Methods for Penetration Test and Split‐Barrel Sampling of Soils, D 1586 – 84. American Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, PA19428‐2959.
    [Google Scholar]
  3. CaiJ. and McMechanG.A.1995. Ray‐based synthesis of bistatic ground‐penetrating radar profiles. Geophysics60, 87–96.
    [Google Scholar]
  4. ChanC.Y. and KnightR.1999. Determining water content and saturation from dielectric measurements in layered materials. Water Resources Research35, 85–93.
    [Google Scholar]
  5. DavisJ.L. and AnnanA.P.1989. Ground‐penetrating radar for high‐resolution mapping of soil and rock stratigraphy. Geophysical Prospecting37, 531–551.
    [Google Scholar]
  6. DavisJ.L. and AnnanA.P.2002. Ground penetrating radar to measure soil water content. In: Methods of Soil Analysis Part 4 ‐ Physical Methods (eds J.H.Dane and G.C.Topp ), pp. 446–463. Soil Science Society of America, Madison, WI.
    [Google Scholar]
  7. Day‐LewisF.D., HarrisJ.M. and GorelickS.M.2002. Time‐lapse inversion of crosswell radar. Geophysics67, 1740–1752.
    [Google Scholar]
  8. HolligerK., MusilM. and MaurerH.R.2001. Ray‐based amplitude tomography for crosshole georadar data: A numerical assessment. Journal of Applied Geophysics47, 285–298.
    [Google Scholar]
  9. JacksonM. and TweetonD.1994. MIGRATOM—Geophysical tomography using wavefront migration and fuzzy constraints . U.S. Bureau of Mines Report of Investigations RI 9497.
    [Google Scholar]
  10. LagerD.L. and LytleR.J.1977. Determining a subsurface electromagnetic profile from high frequency measurements by applying reconstruction technique algorithms. Radio Science12, 249–260.
    [Google Scholar]
  11. NekutA.G.1994. Electromagnetic ray‐tracing tomography. Geophysics59, 371–377.
    [Google Scholar]
  12. OsborneP.S.1969. Analysis of well losses pertaining to artificial recharge. MSc thesis, University of Arizona, Tucson.
    [Google Scholar]
  13. RedmanD., ParkinG. and AnnanP.2000. Borehole GPR measurement of water content during an infiltration experiment. Proceedings of the 8th International Conference on Ground Penetrating Radar, SPIE Vol. 4084, pp. 501–505.
    [Google Scholar]
  14. RuckerD.F. and FerréT.P.A.2003. Near‐surface water content estimation with borehole ground penetrating radar using critically refracted waves. Vadose Zone Journal2, 252–257.
    [Google Scholar]
  15. RuckerD.F. and FerréT.P.A.2004. Correcting water content measurement errors associated with critically refracted first‐arrivals on zero offset profiling borehole ground penetrating radar profiles. Vadose Zone Journal3, 278–287.
    [Google Scholar]
  16. VascoD.W., PetersonD.E.Jr. and LeeJ.H.1997. Ground‐penetrating radar velocity tomography in heterogeneous and anisotropic media. Geophysics62, 1758–1773.
    [Google Scholar]
  17. WilsonL.G. and de CookK.J.1968. Field observations on changes in the subsurface water regime during influent seepage in the Santa Cruz River. Water Resources Research4, 1219–1234.
    [Google Scholar]
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