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REFERENCES

APPENDIX A

The purpose of this appendix is to express $\omega_0=\omega_0(\omega,k_y,k_h)$ and to find the integration limits for $\omega_0$ given the integration limits for $\omega$. Start with the expression for $\omega$:
\begin{displaymath}
\omega^2 = \omega_0^2 + 
{{\omega_0^2 v_h^2} \over {\omega_0^2-v_y^2}}\end{displaymath} (20)
and after reducing

\begin{displaymath}
\omega^2 \omega_0^2 - \omega^2 v_y^2 = 
\omega_0^4 - \omega_0^2 v_y^2 + \omega_0^2 v_h^2\end{displaymath}

and grouping

\begin{displaymath}
\omega_0^4 - \omega_0^2 (\omega^2 + v_y^2 - v_h^2)
+\omega^2 v_y^2 = 0\end{displaymath}

we have
\begin{displaymath}
\omega_0^2 = {1 \over 2} 
(\omega^2+v_y^2-v_h^2 \pm 
{\sqrt {(\omega^2+v_y^2-v_h^2)^2-4 \omega^2 v_y^2}})\end{displaymath} (21)
The discriminant $\Delta$ is

\begin{displaymath}
\Delta =
(\omega-v_y-v_h)(\omega-v_y+v_h)
(\omega+v_y-v_h)(\omega+v_y+v_h).\end{displaymath}

From the conditions on kz in equation (12), $\Delta$ is always positive and therefore $\omega_0^2$ is real.

The integration limits for $\omega_0$ are found by starting with the limits $\omega$ :

\begin{displaymath}
\omega = \mid v_h \mid + \mid v_y \mid\end{displaymath}

and after we square both sides

\begin{displaymath}
\omega^2 = v_h^2+v_y^2+2\mid v_h v_h \mid\end{displaymath}

and replacing $\omega^2$ in the equation for $\omega_0^2$ we have

\begin{displaymath}
\begin{array}
{lcl}
\omega_0^2 & = & \displaystyle{
{1 \over...
 ... \\  & = & \displaystyle{
v_y^2+ \mid v_h v_y \mid}.\end{array}\end{displaymath} (22)


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Stanford Exploration Project
11/17/1997