【摘要】 地震波场模拟能使地震波在地球介质中的传播过程可视化，有助于了解地震波的传播特点。为提高计算效率，通常将三维空间简化为二维处理。但在二维直角坐标下的波场正演无法获取波场的三维特征，对体波振幅特征、面波振幅和相位特征的描述都不甚准确。为此，在柱对称的基本假设下，选择二维柱坐标以模拟弹性体波和面波的波场传播；推导柱坐标下的弹性波方程，对该方程进行有限差分正演，计算柱坐标系下的面波波场。正演模拟结果表明：柱坐标下正演所得波场具备三维空间的振幅和相位特征，体现了该算法的正确性；该算法兼具保持振幅特征与计算效率两方面优势。更多还原

【Abstract】 Seismic wavefield simulation can visualize the propagation process of seismic waves in the interior of the earth, which is helpful for the interpretation of actual seismic data. In order to improve computational efficiency, three-dimensional space is usually reduced to two-dimensional processing. However, the forward modeling of the wave field in 2D rectangular coordinates can not obtain the three-dimensional characteristics of the wave field, and the description of the amplitude characteristics of the body wave, the amplitude and phase characteristics of the surface wave is not accurate. In this paper, two-dimensional cylindrical coordinates are selected to simulate the wave field propagation of elastomer and surface waves under the basic assumption of cylindrical symmetry. The elastic wave equation in a cylindrical coordinate system is derived, and the finite difference forward equation is used to calculate the surface wave field in the cylindrical coordinate system. The results of the forward simulation show that the wave field obtained by forward modeling in cylindrical coordinates has the amplitude and phase characteristics of three-dimensional space, which verifies the correctness of the algorithm and shows that the algorithm has advantages in maintaining the amplitude characteristics and computational efficiency.更多还原