RTM can image steeply dipping reflectors and overturned events.
However, the conventional correlation-based imaging condition in RTM
always produces strong low-frequency artifacts. To suppress these artifacts,
an imaging condition using appropriate decomposed source and receiver wavefields
based on their propagation direction has been applied and examined. This imaging condition contains only the backward scattered events based
on Cartesian directions. The imaging condition discussed in this paper successfully attenuates such
artifacts in complex velocity models compared to applying a low-cut filter. However, there are still remaining artifacts in the
decomposed RTM images. These are caused by the
cross-correlation between the upgoing components of the direct source
wavefields and the downgoing components of the backscattering
of receiver wavefields. Thus, further investigation is still necessary to remove these residual artifacts.