Seismic interferometry refers to the study of interference of seismograms. The principal mathematical operation used to study this interference is the cross-correlation of pairs of seismograms, which can be understood as detecting the traveltime differences of the recorded waves (Curtis et al., 2006). We call the result of the cross-correlation of two seismograms a seismic interferogram. If we assume that the embedded seismic wavelet is the same in both cross-correlated seismograms, we should have a zero-phase wavelet embedded in the corresponding interferogram, which might be a distinctive advantage of interferograms over the original seismograms. We try to exploit the advantage of a zero-phase wavelet in the context of normal moveout velocity analysis, i.e. we try to extract the normal moveout velocity from a gather of seismic interferograms computed from a conventional common-midpoint gather of seismograms. We present in this paper how we approached this problem and conclude that we found clear indication that it is indeed possible to do so. We however also found an ambiguity between velocity and two-way traveltime in the normal moveout analysis of interferograms, resulting in degraded resolution in the corresponding semblance spectra especially for higher traveltimes.
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