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Figures - compare the impulse responses of our algorithm with those of anisotropic
phase shift method.
The medium is a homogeneous, tilted TI medium.
The symmetry axis of the medium is in the (*x*,*z*) plane and is tilted from the vertical direction.
The P-wave velocity in the direction parallel to the symmetry axis is 2000 m/s. The anisotropy parameters
and are 0.4 and 0.2, respectively. The location of the impulse is at *x*=2000 m and *y*=2000 m.
The travel time for the three impulses are 0.4 s, 0.6 s and 0.8 s, respectively.
Figure shows a depth slice of the impulse responses at *z*=1500 m.
Figure (a) is obtained with our algorithm
and Figure (b) is obtained with the anisotropic phase-shift method.
First, Figure (a) is very similar to (b). Second, the depth slice of the impulse response
is not a circle. The wave propagates faster in *y* than in *x* direction. Third, the impulse location
*x*=2000 m and *y*=2000 m is not the center of the impulse response. The impulse response is symmetric along *y*=2000m,
but it is not symmetric along *x*=2000 m.
**filtercom
**

Figure 6 Comparison of the anisotropic plane-wave migration of a synthetic dataset by
the 19-point filter and the new 5-point filter. (a) The density model. (b) The migration result of the 19-point filter.
(c) The migration result of the new 5-point filter.

Figure shows an in-line slice of the impulse responses at *y*=2000 m.
Figure (a) is obtained with our algorithm and Figure (b) is obtained
with the anisotropic phase-shift method.
Figure shows a cross-line slice of the impulse responses at *x*=2000 m.
Figure (a) is obtained with our algorithm and Figure (b) is obtained
with the anisotropic phase-shift method. From Figure and , we can see that
the impulse of our algorithm is very close to that of the anisotropic phase-shift method at low-angle energy
and is different from the the anisotropic phase-shift method at high-angle energy. Since the medium is
homogeneous, the anisotropic phase-shift method is accurate. So our algorithm is accurate for the energy up
to in the impulse response, compared to the anisotropic phase-shift method.

** Next:** Conclusion
** Up:** Numerical example
** Previous:** A synthetic anisotropic dataset
Stanford Exploration Project

5/3/2005