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position
                                                              Migration  shallows,
                                                           migrated  tangent
                                                 two-dimensional
                                                                unmigrated
                                                  unmigrated
                                               a)  Assuming  constant
                                                    from
                                                         swinging  circular  arcs
                                                      along  a  semicircle  drawn
                                                       is
                                                                 updip
                                                       Migration
                      of
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          Snell’s
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              makes
                     discussions
            time  as
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      141
                                                    come
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                  below,
                                                                  event,  moving  points  in  an
                                                                shortens,  and  steepens  an
                                                  an
                                                    trace  could  have
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            travel
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      Profiles
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                                                       event.  b)
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                                common
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                                                         to
                                               6.5
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                                               FIGURE
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                                                                                                               Data  Series
                                       oe                                                                  6.4   Fig   the  Nankai  Trough,  Japan.   Basic
       :                               RRR   SOI                      7   es                               Geophysics,   of a  seismic  profile from  Nanki  Trough,  /POD,  Japan
          Section                      SES                            ——S                                  Earth   University  of Tokyo,  Tokyo,  Japan.
          Time                         ems                              SS                                 Whole   Lillie,   and  depth  conversion  others,  Multi-channel  seismic  reflection  data  across
          Unmigrated                                                                                          Migration   Institute,  Research
         a)                            Aen                                                                    6.4  FIGURE   Ocean
                                                                                                               and
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