Dictionary:DMO (dip moveout) processing

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A seismic processing operation to correct for the fact that, for dipping reflections, the component traces of a CMP gather do not involve a common reflecting point. Dip-moveout processing creates apparent common-reflection-point gathers by a convolution applied to adjacent common-midpoint gathers, with the feature that the moveout with offset for reflections from a dipping bed no longer depend on the dip angle (see Figure C-9b). DMO effectively corrects for the reflection-point smear that results when dipping reflectors are stacked by the CMP method. After DMO is applied, events with various dips stack with the same velocity. DMO stands for dip moveout, but it is different from the classical dip moveout that is simply the effect of dip on arrival times. DMO can be performed in a number of ways, including prestack partial migration (Yilmaz and Claerbout, 1980), time-domain, finite-difference methods (offset continuation) (Bolondi et al., 1982), Fourier-domain implementation (Hale, 1984), integral (Kirchhoff) methods (Deregowski, 1985). Velocity-dependent DMO is usually applied after velocity-dependent NMO. Gardner’s DMO (Forel and Gardner, 1988) applies velocity-independent DMO prior to velocity-dependent NMO. See Figure D-20 and double square-root equation.