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@ARTICLE{Nguyen:49230,
      author       = {Nguyen, F. and Garambois, S. and Jongmans, D. and Pirard,
                      E. and Loke, M. H.},
      title        = {{I}mage processing of 2{D} resistivity data for imaging
                      faults},
      journal      = {Journal of applied geophysics},
      volume       = {57},
      issn         = {0926-9851},
      address      = {Amsterdam [u.a.]},
      publisher    = {Elsevier Science},
      reportid     = {PreJuSER-49230},
      pages        = {260 - 277},
      year         = {2005},
      note         = {Record converted from VDB: 12.11.2012},
      abstract     = {A methodology to locate automatically limits or boundaries
                      between different geological bodies in 2D electrical
                      tomography is proposed, using a crest line extraction
                      process in gradient images, This method is applied on
                      several synthetic models and on field data set acquired on
                      three experimental sites during the European project
                      PALEOSIS where trenches were dug. The results presented in
                      this work are valid for electrical tomographies data
                      collected with a Wenner-alpha array and computed with an
                      1(1) norm (blocky inversion) as optimization method, For the
                      synthetic cases. three geometric contexts are modelled: a
                      vertical and a dipping fault juxtaposing two different
                      geological formations and a step-like structure. A
                      superficial layer can cover each geological structure. In
                      these three situations, the method locates the synthetic
                      faults and layer boundaries, and determines fault
                      displacement but with several limitations. The estimated
                      fault positions correlate exactly with the synthetic ones if
                      a conductive (or no superficial) layer overlies the studied
                      structure. When a resistive layer with a thickness of 6 in
                      covers the model, faults are positioned with a maximum error
                      of 1 m. Moreover, when a resistive and/or a thick top layer
                      is present, the resolution significantly decreases for the
                      fault displacement estimation (error up to $150\%).$ The
                      tests with the synthetic models for surveys using the
                      Wenner-alpha array indicate that the proposed methodology is
                      best suited to vertical and horizontal contacts. Application
                      of the methodology to real data sets shows that a lateral
                      resistivity contrast of 1:5 1:10 leads to exact faults
                      location. A fault contact with a resistivity contrast of
                      1:0.75 and overlaid by a resistive layer with a thickness or
                      1 m gives an error location ranging from 1 to 3 m. Moreover,
                      no result is obtained for a contact with very low contrasts
                      (similar to 1:0.85) overlaid by a resistive soil. The method
                      shows poor results when vertical gradients are greater than
                      horizontal ones. This kind of image processing technique
                      should be systematically used for improving the
                      objectiveness of tomography interpretation when looking for
                      limits between geological objects. (c) 2005 Elsevier B.V.
                      All rights reserved.},
      keywords     = {J (WoSType)},
      cin          = {ICG-IV},
      ddc          = {620},
      cid          = {I:(DE-Juel1)VDB50},
      pnm          = {Chemie und Dynamik der Geo-Biosphäre},
      pid          = {G:(DE-Juel1)FUEK257},
      shelfmark    = {Geosciences, Multidisciplinary / Mining $\&$ Mineral
                      Processing},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000230774800003},
      doi          = {10.1016/j.jappgeo.2005.02.001},
      url          = {https://juser.fz-juelich.de/record/49230},
}