I derive and analyze an explicit formula for a generalized semblance
attribute, which is suitable for velocity analysis of prestack
seismic gathers with distinct amplitude trends. While the
conventional semblance can be interpreted as squared correlation
with a constant, the
![$ AB$](img1.png)
semblance is defined as a correlation with a
trend. This measure is particularly attractive for analyzing class
II AVO anomalies and converted waves. Analytical derivations and
numerical experiments show that the resolution of the
![$ AB$](img1.png)
semblance
is approximately twice lower than that of the conventional
semblance. However, this does not prevent it from being an effective
attribute. I use synthetic and field data examples to demonstrate
the improvements in velocity analysis from
![$ AB$](img1.png)
semblance.