Incoherence is a measure of the difference between adjacent waveforms or traces in a seismic volume. There are multiple ways to calculate incoherence that include Cross correlation, Semblance, Variance, Eigen structure method, Gradient Structure Tensor-based Coherence, and Least Squares Coherence (Bednar, 1998). Here is an example taken from Fairfield Geotechnologies Delaware Basin PSDM showing the seismic volume next to the incoherence volume.
Incoherence volumes are used to enhance the ability to interpret structural and stratigraphic discontinuities. Incoherence is heavily impacted by noise due to the random nature of change it creates which is highlighted by the difference it causes between traces. A stratal slice of the incoherence volume over a generally continuous reflector clearly highlights faults.
Taylor McKay is Jr. Geophysicist focused on understanding the value that seismic attributes and rock properties bring to subsurface interpretation.
Bednar, J. (1998). Least Squares dip and coherency attributes. The Leading Edge, 17 (6). doi:https://doi.org/10.1190/1.1438...
Taylor McKay, Fairfield Geotechologies Jr. Geophysicist