Velocidad media cuadrática
Root-mean-square velocity. For a series of parallel layers of velocity Vi, where the traveltime for seismic energy perpendicularly through each is ti, the rms velocity for travel perpendicular to the layers is
The average velocity for this path, , on the other hand, is
The stacking velocity, the velocity determined from velocity analysis based on normal-moveout measurements, is often used to approximate rms velocity; this is valid only in the limit as the offset approaches zero where interfaces and velocities are horizontal and isotropic.