随机均匀介质地震波振幅属性研究

基于二维随机-均匀介质模型，讨论了复杂介质中由非均匀体产生的散射波的特性，同时讨论了不同尺度地质体条件下散射波对直达波和反射波的影响。建立了11个不同尺度的随机-均匀介质模型，并利用有限差分法进行了正演模拟。基于正演模拟结果，提取了直达波、散射波和反射波的均方根振幅、平均绝对振幅、振幅峰态和绝对振幅积分4种振幅属性，绘制了振幅属性与非均匀地质体尺度的关系曲线。研究认为，当非均匀地质体尺度与地震波长相近或更小时，3种地震波的4种振幅属性值随地质体尺度的增大而增大；当非均匀地质体尺度比地震波长大或大很多时，随着地质体尺度的增大，直达波和反射波的4种振幅属性值均呈减小趋势，散射波的4种振幅属性值呈增大趋势。

Study on amplitude attributes of seismic wave in random-uniform medium model

Based on 2-D random-uniform medium model,we discussed the characteristics of scattering wave produced by heterogeneous bodies in complex medium,as well as the impact of scattering wave on direct wave and reflected wave with different-scale geologic bodies.Eleven different-scale random-uniform medium models were built,and the finite-difference method was used to carry out forward modeling.Based on forward modeling results,some amplitude attributes of direct wave,scattered wave and reflected wave were extracted,including root-mean-square amplitude,mean absolute amplitude,amplitude kurtosis and absolute amplitude integration.The relationship curves between amplitude attributes and the scale of heterogeneous geologic bodies was mapped.The research results show that when the scale of heterogeneous geologic bodies is near to or smaller than the seismic wavelength, four attribute values of the three kinds of seismic waves increase with the scale of geologic bodies increasing;when the scale of heterogeneous geologic bodies is larger or much larger than the seismic wavelength,with the scale of geologic bodies increasing,four attribute values of direct wave and reflected wave decrease,but the four attribute values of scattering wave increases.