reflection seismology Reflection seismology (or seismic reflection) is a method of exploration geophysics that uses the principles of seismology to estimate the properties of the Earth's subsurface from reflected seismic waves. The method requires a controlled seis ...

, stacking velocity, or

Normal Moveout In reflection seismology, normal moveout (NMO) describes the effect that the distance between a seismic source and a receiver (the offset) has on the arrival time of a reflection in the form of an increase of time with offset. The relationship bet ...

(NMO) velocity, is the value of the seismic velocity obtained from the best fit of the traveltime curve by a hyperbola.Schlumberger Oilfield Glossary
/ref>. The hyperbolic approximation to the traveltime curve (two-way travel time versus offset) is known as Normal moveout (NMO). The procedure of finding the best fit on common midpoint (CMP) seismic gathers is known as NMO velocity analysis.

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Seismology {{seismology-stub