| Function type | Instantaneous velocity is a function of time. |
| Definition of parameters |
V0 = constant velocity factor. α = constant acceleration factor. T = bottom seismic time of the layer. |
| Operational applications | Useful when geology presents non-linear compaction from the surface. |
$$
V_{inst} = V0 + α \times t
$$
$$
DZ = \int_{t_0}^{t_0+DT} V_{inst}dt = \int_{t_0}^{t_0+DT} (V0+α \times t) \times dt
$$
$$
DZ = \left( V0 + α \times t_0 + \frac{α}{2} \times DT \right) \times DT
$$
$$
V_{int} = V0 + α \times t_0 + \frac{α}{2} \times DT
$$