REFERENCES

Biondi, B., 1992, Solving the frequency-dependent Eikonal equation: 62nd Ann. Internat. Mtg., Soc. Expl. Geophys., Expanded Abstracts, 1315-1319.

Cervený, V., Popov, M. M., and Psencik, I., 1982, Computation of wave fields in inhomogenous media: Geophys. J. Roy. Astr. Soc., 70, 109-128.

Claerbout, J. F., 1985, Tuning up Fourier Migrations:, in Imaging the Earth's Interior Blackwell Scientific Publications, 272-274.

Gazdag, J., and Sguazzero, P., 1984, Migration of seismic data by phase-shift plus interpolation: Geophysics, 49, no. 2, 124-131.

van Trier, J., and Symes, W. W., 1991, Upwind finite-difference calculation of traveltimes: Geophysics, 56, no. 6, 812-821.

 

over-three
Figure 7 Modeling in a linear velocity gradient in depth. A time slice of the Green's function, depth is plotted upwards. The plot on the bottom was computed by PSPI in rectangular coordinates. The plot in the middle was computed by PSPI in a polar coordinate frame. The plot on the top was computed using the $45^\circ$ wave equation in polar coordinates.

 

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Figure 8 Modeling in a two layer model. A time slice of the Green's function, depth is plotted upwards. The plot on the bottom was computed by PSPI in rectangular coordinates. The plot in the middle was computed by PSPI in a polar coordinate frame. The plot on the top was computed using the $45^\circ$ wave equation in polar coordinates.

 

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Figure 9 Modeling in medium with a Gaussian anomaly. A time slice of the Green's function, depth is plotted upwards. The plot on the bottom was computed by PSPI in rectangular coordinates. The plot in the middle was computed by PSPI in a polar coordinate frame. The plot on the top was computed using the $45^\circ$ wave equation in polar coordinates.