Semblance analysis

Prior to the discovery of this method, identifying the main reflections produced by the many layers under the ground was fairly difficult.

The NIP is where you have the shot and the geophone in the same location and the path taken by the recorded sound waves is perpendicular to the boundaries between the layers.

The velocity data is used to correct the curves of the hyperbolas and create a flat line where all points are at an equal depth.

Semblance analysis will not work properly when the offset from the shot is greater than the depth of the reflecting layers because the data no longer has a hyperbolic pattern.

To make moveout analysis suitable for data with polarity reversals a method known as AK semblance developed.