Reflection features of planar acoustic waves from rough interfaces
平面声波在粗糙界面上的反射特征研究

Based on Rayleigh's hypothesis of rough interface,reflection features of planar acoustic waves from a rough interface with rapid-jumped cosine style are studied.The study indicates that such a interface has a response similar to that of an appropriately chosen transient layer at the same position.The thickness of the transient layer is equal to the fluctuant amplitude of the rough interface,and the velocity and density are the average of corresponding parameters of upper and lower media.For a small-scale rough interface imbed deeply,the dispersion characteristics of seismic reflections/diffractions are analyzed.It is deduced that the travel-time of reflections/diffractions consists of three parts: zero-offset reflection time(t-0),normal moveout and rough moveout.The rough moveout is related to the order of diffractions,while it is independent of receiver's location and t-0 time.Diffractions appear after reflection by a fixed moveout.And only when the rough wavelength of the interface is similar to the wavelength of seismic wave,diffraction can be observed clearly in the seismic record.This result offers a basis for seismic data processing of rough interfaces.