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The point response

Another simple geometry is a reflecting point within the earth. A wave incident on the point from any direction reflects waves in all directions. This geometry is particularly important because any model is a superposition of such point scatterers. Figure 16 shows an example.

 
twopoint
twopoint
Figure 16
Response of two point scatterers. Note the flat spots.


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The curves in Figure 16 include flat spots for the same reasons that some of the curves in figures12 and 13 were straight lines.

The point-scatterer geometry for a point located at (x,z) is shown in Figure 17.

 
pgeometry
pgeometry
Figure 17
Geometry of a point scatterer.


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The equation for travel time t is the sum of the two travel paths  
 \begin{displaymath}
t\,v\ \eq \ \sqrt { z^2\ +\ {( s \ -\ x ) }^2} 
\ +\ \sqrt { z^2 \ +\ {( g \ -\ x )}^2}\end{displaymath} (5)


previous up next print clean
Next: Cheops' pyramid Up: INTRODUCTION TO DIP Previous: The dipping bed
Stanford Exploration Project
10/31/1997