中文摘要：

目前,完全的3D弹性波数值模拟计算仍然需要庞大的计算资源,而2D弹性波数值模拟,又不能准确地近似3D数值模拟.因此,本文在较高数值精度的一阶应力-速度弹性波动方程的基础上,采用时间错格差分拟谱方法在2D模型介质中计算3D弹性波场,即2.5D数值模拟.并将3D计算结果与2.5D和2D结果进行比较,发现2.5D模拟结果在波场形态和振幅方面比2D模拟结果更接近3D模拟结果,从而证实了2.5D数值模拟比2D数值模拟可以更好地近似3D波场数值模拟,同时证实了时间错格差分拟谱方法是一种高精度、高效率的正演模拟方法.

英文摘要：

At present, pure 3D elastic wave numerical simulations still require huge computation resources and 2D e- lastic wave numerical simulations can not accurately represent 3D situation. Thus this paper puts forwards a kind of 2. 5D numerical simulation method which computes 3D elastic wave fields in 2D media by using the time-staggered difference pseudospectral method based on high accurate one-order elastic wave equations expressed with velocity and stress. Compared with 2D and 3D simulation results, the 2. 5D results are closer to 3D results than 2D results in waveformes and amplitudes. And it confirms that the 2.5D method proposed in this paper, in 3D waveform simulation, is better than 2D method to approximate the 3D wave field and the time-staggered difference pseudospectral method is efficient and accurate in forward modeling.