过渡层反射特征及脉冲波的振幅调谐现象

Reflectance signatures of transitional layer and its tuning effects to the amplitudes of pulsating waves.

从弹性动力学理论出发 ,详细推导了速度线性变化的过渡性地层在平面波法向入射时的反射波响应 ,并分析了其反射的滤波特性 ;说明了在不同厚度下 ,过渡层的振幅频率特性和相位频率特性的变化规律 ,给出了数值算例。数值算例表明 ,对于具有某一特定主频的脉冲波入射到均匀层—过渡层—均匀层界面上时 ,在过渡层为一相应厚度时表现出反射振幅明显增强的现象 ,即所谓的振幅调谐现象。鉴于两者的良好对应关系 。

Based on the theory of elastodynamics, this paper presents a detailed discussion about the reflection responses of a transitional layer with linearly varied velocity and its filtering properties under the assumption that the plane waves are normally incident into the layer. The characteristics of amplitude frequency and phase frequency under different thickness of the layer are illustrated with numerical examples. Numerical examples show that for pulsating waves with certain dominant frequency, when they are incident at interfaces between homogeneous layer to transitional layer and transitional layer to homogeneous layer, reflection amplitude will increase significantly if transitional layer is with certain thickness. That is referred to as amplitude tuning effect. Due to the good coincidence relation between the two, this phenomenon can be used to guide seismic interpretation.