中文摘要：

针对一类模型发生局部改变后的正演模拟问题，提出了一种快速算法，并且结合有限差分法，给出了有限差分时间分段法．针对四维时间推移问题进行了数值模拟．数值计算的结果表明该有限差分时间分段法是一种快速有效的算法．

英文摘要：

A fast algorithm is put forward for a kind of forward model which is locally changed. Combined with finite - difterence method, a finite - difference time - segment method is proposed. The method is used in 4 - D time - lapse seismic. The result of numerical tests indicates that the method is effective for the forward model of time - lapse seismic.