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基于波动方程的地震波正演模拟能够准确揭示波在介质中传播的振幅、频率与相位变化,真实地反映出波的动力学特征。有限差分法因其精度高、计算效率高而成为波场数值模拟的一个重要方法。根据地震波的近似方程———声波方程,采用二阶有限差分网格数值算法,利用透明边界条件,设计典型地质模型,进行地面波场的地震记录模拟。通过稳定性条件分析、震源子波优选以及频散抑制,成功合成了倾斜地层模型与正断层模型的地面共炮点波场记录,直观地显示出直达波、反射波、绕射波等丰富的波场信息,获取各模型的波场快照。结果表明,有限差分法结合透明边界条件对于获取介质丰富的波场信息具有很大的优势。
The seismic wave forward modeling based on the wave equation can accurately reveal the amplitude, frequency and phase of the wave propagating in the medium, which truly reflects the dynamic characteristics of the wave. Finite difference method is an important method of numerical simulation of wave field because of its high precision and high computational efficiency. According to the approximate equation of seismic wave --- acoustic wave equation, the second-order finite difference mesh numerical algorithm is used to design the typical geological model using the transparent boundary conditions to simulate the seismic wave in the terrestrial wave field. Through the analysis of stability conditions, the selection of source wavelet and the suppression of dispersion, the co-ordinate spot wavefield record of the oblique formation model and the normal fault model has been successfully synthesized, which shows the richness of the direct wave, the reflected wave and the diffraction wave Wavefield information, get a snapshot of the wave field of each model. The results show that the finite difference method combined with the transparent boundary conditions has great advantages for obtaining rich wavefield information of medium.