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Up: PRESTACK MIGRATION
Previous: Cheops' pyramid
Denoting the horizontal coordinate of the scattering point by
Equation (8.1) in -space is
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(5) |
A basic insight into equation (8.1) is to notice
that at constant-offset and constant travel time
the locus of possible reflectors is
an ellipse in the -plane centered at .
The reason it is an ellipse
follows from the geometric definition of an ellipse.
To draw an ellipse,
place a nail or tack into on Figure 8.1
and another into .
Connect the tacks by a string
that is exactly long enough to go through .
An ellipse going through may be constructed
by sliding a pencil along the string,
keeping the string tight.
The string keeps the total distance constant as is shown in
Figure 8.3
ellipse1
Figure 3.
Prestack migration ellipse, the locus of all scatterers with
constant traveltime for source S and receiver G.
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Replacing depth in equation (8.5)
by the vertical traveltime depth
we get
|
(6) |
Next: Constant offset migration
Up: PRESTACK MIGRATION
Previous: Cheops' pyramid
2009-03-16