波场模拟的高斯波包叠加方法

2012年 51卷 第No. 4-期
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A new wave field modeling method by using Gaussian Packets
同济大学海洋与地球科学学院,上海200092
Li Hui,School of Ocean and Earth Science, Tongji University, Shanghai 200092, China
高斯波包(Gaussian Packet)是一种在高频渐进理论下描述波传播的方法,对不同高斯波包叠加
可以得到给定点震源函数产生的波场。常速介质中,高斯波包按中心射线出射角度积分存在解析
表达式,把该表达式与Gabor点源函数产生波场的解析式对比发现两者是等价的。基于此,利用波
动方程关于震源函数的线性性,提出一种利用高斯波包叠加计算任意点源函数产生的波场的新方
法。该正演方法可以应用于叠前深度偏移中。对比高斯波包叠加与有限差分法计算的点源波场结
果可以看出,两者相差很小。叠前深度偏移的数值实验结果表明,该高斯波包正演的新方法有效
可行。
Gaussian Packet describes the propagation of seismic wave in the high-frequency asymptotic theory whose
envelopes at given time are nearly Gaussian functions. We prove that the wave field generated by a given
Gabor function can be calculated by integrating Gaussian packets over take-off angles. The seismic source
function can be decomposed into a series of Gabor functions, and we presented a new method which can
simulate the wave field generated by any source function using Gaussian packets. Also, this method can be
used in reverse time migration. Numerical experiments of prestack depth migration demonstrate the validity
of Gaussian Packets modeling.
高斯波包; Gabor函数; Gabor分解; 高斯波包偏移;
Gaussian Packet; Gabor function; Gabor decomposition; Gaussian Packets migration;
10.3969/j.issn.1000-1441.2012.04.002