Abstract:
There are two possible approaches to the study of nonlinear phenomena. The first is to gear the observation system to the observation of nonlinear effects (multiple harmonics, sum and difference harmonics, and so on) that are known from other areas of physics, primarily acoustics. The second approach involves the testing of the applicability of linear equations for description of the propagation of seismic waves. If the linear relationships are correct to within experimental error, then nonlinear effects may be neglected, at least at the same error level. The problem of detecting nonlinear effects thus reduces to increasing accuracy of the measurement. This paper proposes to focus on the second approach, and it demonstrates how effects detected by the first approach may take on a quite different appearance under the second approach.