Reply to comment on 'Reverse time migration with source wavefield reconstruction strategy'

Liu and Liu (2013) point out that the source wavefield can be reconstructed accurately with only one single layer of the wavefield stored near the boundary. But it increases the algorithm complexity for the wavefield forward propagation. Consequently, the parallel efficiency of the algorithm is decreased. If multiple layers of the wavefield near the boundaries are stored, the source wavefield can be perfectly reconstructed and the efficiency of the algorithm is high. Unfortunately, the amount of data storage will be increased dramatically. To reduce the amount of data storage and keep a relatively high efficiency, we only store a single layer of the wavefield near the boundary and reconstruct the source wavefield approximately. For practical RTM, the optimal source wavefield reconstruction strategy can be selected dynamically. To fully reconstruct the source wavefield backwards in time, we point out that the re-propagation effect at the source position must be removed. The time-reversal technique in the attenuating media is also discussed, and we consider the regularized wave equation of back propagation as a promising and practical way.