Conclusions

A reverse-time migration algorithm expressed as the conjugate of forward time-extrapolation modeling is presented for both 1-D and 2-D geometries. The conjugate operator is obtained by formulating the forward operator explicitly and transposing the forward operator. The algorithm is tested by a numerical experiment for a 1-D layered model. A method to suppress artifacts, which are caused by the intrinsic non-unitary property of the operator, is introduced using a least-squares optimization technique.