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从各向同性非均匀介质中弹性波波动方程出发，导出了在弱不均匀条件下，频率－波数域衍射场方程，给出了格林函数解析解。在电磁波地球物理层析成像数据合成的基础上，用类“体电流法（ＶＣＭ）”，将解析解线性化，得到未作Ｂｏｒｎ近似或Ｒｙｔｏｖ近似的衍射场数值解，便于计算合成数据。采用迭代法进行反演，每步迭代中，采用等比Ｎｅｕｍａｎｎ级数解；反问题用ＳＶＤ法求解，探讨了阻尼因子的取法。数值模型试验表明，这种算法是有效和成功的，成像的分辨率较高，对介质的均匀性要求有所降低，为实际应用创造了进一步条件。
Starting from the wave equation of elasticity in isotropic inhomogeneous medium, the equation of the diffraction field in the frequency-wave number domain under weak non-uniform conditions is derived, and the analytical solution of Green’s function is given. On the basis of electromagnetic geophysical tomography data synthesis, by using “body current method (VCM)”, the analytic solution is linearized and the numerical solution of the diffraction field without Born approximation or Rytov approximation is obtained, which makes it easy to calculate the synthetic data. The iterative method is used to perform inversion. In each iteration, the equivalent Neumann series solution is used. The inverse problem is solved by SVD method, and the damping factor is taken into account. Numerical experiments show that the proposed algorithm is effective and successful. The imaging resolution is high and the uniformity of the medium is reduced, which creates further conditions for practical application.