We compute a version of the Shannon entropy S of snapshots of a seismic wave ﬁeld as it propagates. S is argued to be a measure of the degree of either multiple scattering, or attenuation, or both, experienced by the wave, evolving similarly regardless of which process dominates in a given example. Invoking it, therefore, forces us to reject the distinction between intrinsic and extrinsic attenuation, and allows us to place thin-bed reverberations above and below the resolving power of the experiment on an equal footing should we decide to do so. S is easily computable, as is shown with both synthetic (“wave in a box”) examples and a ﬁeld VSP example. It relies on stable estimates of the histograms of wave amplitude values, and the best way of doing this is still under investigation.
View full article as PDF (2.18 Mb)