Another drawback of this imaging condition is that it creates image artifacts when there is a complex propagation pattern, e.g., a low velocity anomaly that cause wavefield multipathing. Let us consider waves propagating in a homogeneous medium with a velocity anomaly and a flat reflector. After the wave traveling directly from the shot to the reflector arrives, a second wave arrives, which has traveled along a different path due to the low velocity anomaly. If the second wave is not accounted for in the imaging process, the single reflector will be imaged as more than one reflector. This could mislead the geological interpretation.
In this paper, we introduce an imaging condition that computes the reflection strength as the zero lag of the deconvolution of the receiver wavefield by the source wavefield. This new process can account for the second wave arrival in the imaging. We implemented two equivalent deconvolution methods: one in the time domain based on least-squares inversion filtering and the other in the Fourier domain.
We illustrate the wavefield deconvolution imaging condition with two different data sets. One created by the convolution of a minimum-phase, band-limited wavelet with a spike series, and the other by wave equation modeling and downward propagation.