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145
     Profiles
     Reflection
     on
      Structures
      of
      Appearance
    Sai  ae
          of  an  migrated  Unmigrated  and   6.9  FIGURE  profiles  showing  an  anticline.  seismic  Th CLIN  a   AN   lines).   (0@s)  euly  jeAely,  ABAA-OML               (08s)  ew,  jeAReLL  ABAA-OML   por-   a   is   a   is   and          con-   flanks   surface
                                                                                       is
                                                                                    section,
      Profiles   Seismic  expression   two  between   (dashed                          structure   effect   diffraction   events   to   back   the   6.12a).  The   diffractions   Migration
      Reflection   line)   reflectors                                               unmigrated   the   If   (concave-upward)   6.10b).  The   the   crossing   diffraction   positions   on   “hummocky,”   (Fig.   buried-focus   6.12c).
      Seismic   6.8  FIGURE   anticline  (solid   horizontal                        an   On   6.10c).   Fig.   bottom   (Fig.   buried  focus;   two   The   the   proper   or   synclines   (Fig.   ties
      Of                                                         OWI  JOACLL        Effect)   2’   in   the   surface   or   6.10c).   inverts   their   undulating,   and   above   bow
      Interpretation   yideq   yideg         eu]  [PABLL          ACM-OML           “Bow  Tie”   and   (1’   from   the  below   point,   Fig.   in   (3’   Migration   to  events   An   anticlines   cross   highs   numerous
                                              ACM -OML


      Tectonic                 1  1  +  4          i   Out              Event       or   syncline   a   reflections   point   a   at   crossing   the   syncline   tie.   bow   crossing   Synclines   adjacent   of   structural   in  resulting


      And                 Raypaths   |   +   dd,       Spread   Area    Collapses   Smaller  Area   Focus,”   of   axis   incidence   cross   from   the   a   the   6.10d;  6.11).   and   series   a   the   6.12b),
      Structural                          Section   Time      Large      Section      to          (“Buried   the  above   normal   will  syncline   radiates   that   beneath  event   resemble   may   moves   and   (Figs.   Anticlines   of   to  similar   from  events   (Fig.





      Chapter 6   a)  Anticline Model   Z   Incidence   No   +  !  +  '      Unmigrated   “anticline   Over   -   Time  Migrated   Migration   Back   Syncline   cross  events   enough,   deep   the   of   tion   diffraction   hyperbolic   diffraction   upward   cave   syncline   the   of   Series   effects  shows   spread-out   lows   the   from



      144                 Normal   b)   ot           c)       d)
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