Abstract
In the field of nonlinear waves, there exist two kinds of waves, i.e., one is Non-Coupled Simple Wave (nonlinear P wave) and Coupled Simple Wave (nonlinear S wave). In this paper, the problem is limitted to the two-dimensional case. After numerical computations, we have then found that the behavior of waves in the nonlinear wave field is governed by the theory of Simple Waves. Even complex wave form can be analyzed as composite Simple Waves.