In an effort to understand the transmission effects of localized heterogenities in the subsurface, we present the travel-time and amplitude distortions caused by localized variations in velocity and absorption. To examine the relative impact of velocity and absorption heterogeneities on seismic events, we conducted numerical experiments using visco-acoustic finite-difference modeling of the linearized wave-equation for Newtonian fluids. We analyzed the distortions in the midpoint-offset domain. We find that the distortion caused by an anomaly that is both slow and absorptive is different from that an anomaly that is either slow or absorptive, but not both. Our results also indicate that amplitude distortion of highly absorptive anomalies (
) can be comparable to that of small velocity variation (less than
), and therefore absorption must be considered in seismic amplitude inversion and AVO analysis.
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