Predicting Migration Velocity Anomalies
, by Paul J. Fowler
In SEP-51 (Fowler, 1987) I derived a linear operator that relates perturbations in interval slownesses to the resultant changes
in the migration slownesses observed along dipping reflectors. This operator can be represented as a filtered version of
a tomographic back-projection operator. For flat beds it reduces to the stacking slowness operator
studied by Toldi (1985). For dipping beds the operator still resembles the flat dip one, but
is skewed by the effect of the dip. This behavior can be illustrated clearly using pictures of the
operator for a fixed reflecting point in the subsurface. Predictions of changes in migration slowness derived using this linear operator
closely match those measured from synthetic data.