Generally speaking, the approximate analytical QVOA equation (see (1) below) is similar to the analogous AVOA equation.
Also, I compare the results with the best AVOA technique from  with the use of synthetic seismograms with attenuation and noise.
In the QVOA techniques (as in AVOA), one uses 3D seismic data obtained from the receivers located on the ground surface as if at the points of a rectangular grid.
As a result of this replacement, two additional techniques arise, approximate truncated technique (AT) and approximate sectored technique (AS), which are similar to the linear and sector AVOA methods (see ).
Equation (6) is the same as the equation for the general method of AVOA , except for the replacement of the amplitude function T in it by attenuation factor [alpha].
Examples of operations that should be avoided include multiplication of impulse by window functions to reduce the influence of the time window borders and smoothing impulse by filters which was offered for AVOA in .
It is not obvious that the AVOA methods will give good results in predicting [[psi].sub.0], if applied to the seismograms with viscous attenuation, since they are based on the equation for elastic media.
Graphs of the amplitude function T (which is used in the AVOA method instead of [alpha]), similar to Figure 2, show much smaller dependence on noise than the graphs for the attenuation factor [alpha], and therefore one can expect less accuracy of QVOA techniques.
In Figures 12 and 13, I present the error of calculated [[psi].sub.0] for the best QVOA techniques (C, EG, and TEG) and AVOA General method (see ) for the seismograms with noise and the asymmetric set of azimuths.
It should be noted that the results of QVOA techniques lay mostly between the results of the AVOA method for top and bottom.
In this part of experiment, the results of AVOA and QVOA look comparable, except some instability of the AVOA results at the bottom.