Abstract: By studying the relations between the time graphs of the diffracted wave
and the reflective wave as well as the characteristics before and after the
NMO of the diffracted waves，e m phasis is laid on the discussion of the
reason why the largest graphs diffracted wave amplitudes occur in the top of the diffracted wave to and why the amplitudes attenuated at great speed
occurin the tails of the diffracted wave graphs to in the horizontal stack
section, when the seismic line is normal to a fault edge in the case of
the sa m e buried depths h of the diffracted point and different values L(the
distance from the shotpoint to the projection point of the diffracted point
on the surface.)