我们知道,当地震波入射到厚层(即厚度比入射波波长大得多),并在其表面发生反射时,反射波的频率只与入射波的频率有关。但是,当波入射到薄层(即厚度比入射波波长小得多),并在其表面发生反射时,反射波的频率不仅与入射波的频率有关,而 We know that when a local shock wave is incident on a thick layer (that is, the thickness is much larger than the incident wavelength) and reflected on its surface, the frequency of the reflected wave is only related to the frequency of the incident wave. However, when a wave is incident on a thin layer (that is, the thickness is much shorter than the wavelength of the incident wave) and the reflection occurs on the surface thereof, the frequency of the reflected wave depends not only on the frequency of the incident wave but