The anisotropic properties of subsurface media cause waveform distortions in seismic wave propagation, resulting in a negative influence on seismic imaging. In addition, wavefields simulated by the conventional coupled pseudo-acoustic equation are not only affected by SV-wave artifacts but are also limited by anisotropic parameters. We propose a least-squares reverse time migration (LSRTM) method based on the pure qP-wave equation in vertically transverse isotropic media. A finite difference and fast Fourier transform method, which can improve the efficiency of the numerical simulation compared to a pseudo-spectral method, is used to solve the pure qP-wave equation. We derive the corresponding demigration operator, migration operator, and gradient updating formula to implement the LSRTM. Numerical tests on the Hess model and field data confirm that the proposed method has a good correction effect for the travel time deviation caused by underground anisotropic media. Further, it significantly suppresses the migration noise, balances the imaging amplitude, and improves the imaging resolution.

地下介质的各向异性会引起地震波传播中的波形畸变，从而对地震成像产生负面影响。另外，由常规耦合伪声方程模拟的波场不仅受​​到SV波伪影的影响，而且还受到各向异性参数的限制。我们在垂直横观各向同性介质中基于纯qP波动方程提出了最小二乘逆时偏移（LSRTM）方法。使用有限差分和快速傅立叶变换方法来求解纯qP波动方程，与伪谱方法相比，该方法可以提高数值模拟的效率。我们导出相应的反偏移算子，偏移算子和梯度更新公式以实现LSRTM。对Hess模型和现场数据进行的数值测试证实，该方法对地下各向异性介质引起的传播时间偏差具有良好的校正效果。此外，它显着抑制了迁移噪声，平衡了成像振幅，并提高了成像分辨率。