For example, suppose a CMP gather is divided into two parts, say, inner traces A and outer traces B . Alternately, we could pause, do some thinking about statistics, and then choose to combine them with some weighting function. A three-trace CMP gather decomposed by traces. At the left, impulses on the data are interpolated, depicting a hyperbola. At the right, data points are expanded into migration semicircles, each of which goes through zero offset at the apex of the hyperbola.
Semicircles depict the separate downward continuation of each trace.
Each semicircle goes through zero offset, giving the appropriately stretched, NMOed trace. The idea of using a weighting function is a drastic departure from our previous style of analysis. They are many. Signal and noise variances play a role. Some channels may be noisy or absent.