Influence Of Smoothing Velocity On Reflected Seismic Signal

The usual velocity interface can be converted into an inhomogeneous thin layer by smoothing, making the layer reflection different from original interface reflection obviously. In order to analyze the influence such smoothing on reflected wave signal quantitatively, we take an incident plane wave into account and derive the formula of the reflected signal that is expressed by the reflection coefficient of the corresponding inhomogeneous thin layer. An iterative solution to reflection coefficient equation is used to obtain its reflection coefficient, and we make sure the accuracy of this iteration algorithm in comparison with analytical results in the classical Epstein transition layer. Comparison of final received signals reflected by the usual interface and that by its smoothed inhomogeneous thin layer shows that the arrival time of reflected wave signal remains unchanged while its dominant frequency and energy decrease as the number of smoothing increases. In particular, the signal energy with low smoothing number decreases more faster than that with high smoothing number.