Simple geometrical considerations show that the zero offset section
obtained from a Common Mid-Point (CMP) gather in presence of a single point
diffractor is a combination of:
(i) Part of the diffraction hyperbola of the scatterer.
(ii) Other patterns depending on the relative locations of the diffractor and the CMP
and on the midpoint spacing (aliases).
Superimposing many CMP's, pattern (i) is strengthened while pattern (ii) is not; thus
patterns (ii) become of negligible amplitude if the CMP sampling rate is high enough.
The geometrical approach can explain the Dip Moveout (DMO) action on aliasing noise,
clarifying why the latter cannot be removed at wavenumbers that are integer multiple
of the Nyquist of the survey.
STANFORD