Seismic interferometry, intrinsic losses and Q-estimation∗

Seismic interferometry is the process of generating new seismic traces from the crosscorrelation, convolution or deconvolution of existing traces. One of the starting assumptions for deriving the representations for seismic interferometry by crosscorrelation is that there is no intrinsic loss in the medium where the recordings are performed. In practice, this condition is not always met. Here, we investigate the effect of intrinsic losses in the medium on the results retrieved from seismic interferometry by cross-correlation. First, we show results from a laboratory experiment in a homogeneous sand chamber with strong losses. Then, using numerical modelling results, we show that in the case of a lossy medium ghost reflections will appear in the cross-correlation result when internal multiple scattering occurs. We also show that if a loss compensation is applied to the traces to be correlated, these ghosts in the retrieved result can be weakened, can disappear, or can reverse their polarity. This compensation process can be used to estimate the quality factor in the medium.