High Accurate Elastic Modeling by Use of the Fourier Transform

准确、快速的建模方法对于地震勘探资料的解释，特别是对复杂精细构造资料的解释具有重要意义。本文在利用傅里叶变换建立了二维和三维声学和弹性建模算法后，考虑了稳定性条件、声源特征和透明边界条件。使用开发的算法，(1)有限差分法与傅里叶变换算法的比较；(2)位移场算法与应变场算法的比较；(3)反射波、透射波与入射波振幅之比的反射系数和透射率的计算；(4)考虑Q值的粘弹性介质中模拟算法的发展；(5)各向异性介质中剪切波分裂模拟算法的发展(6)利用塔纳断裂附近的VSP资料估算横波偏振各向异性。

The accurate and high speed modeling method becomes very important for the interpretation of the seismic prospecting data, especially for the data from the subtle and complicated structures. In the present paper, after the two and three dimensional acoustic and elastic modeling algorithm by use of the Fourier transform was developed, the condition of stability, the source signature and the transparent boundary condition were considered. Using the developed algorithm, the following items were executed.(1) The comparison of the algorithms by use of the finite difference method with that by the Fourier transform.(2) The comparison of the algorithm by displacement field with that by strain field by use of the Fourier transform.(3) The calculation of the reflection coefficient and the transmission coefficient from the ratio of the amplitude of reflected and transmitted waves with that of the incident waves.(4) The development of the modeling algorithm in visco-elastic media taken into account of Q value.(5) The development of the modeling algorithm of Shear-wave splitting in anisotropic media.(6) The estimation of Shear-wave polarization anisotropy from VSP data near the Tanna fault.