AbstractIt is well known that interval velocities can be determined from common‐reflection‐point moveout times. However, the mathematics becomes complicated in the general case ofnhomogeneous layers with curved interfaces dipping in three dimensions.In this paper the problem is solved by mathematical induction using the second power terms only of the Taylor series which represents the moveout time as a function of the coordinate differences between shot and geophone points. Moreover, the zero‐offset reflection times of thenth interface in a certain area surrounding the point of interest have to be known. Then—I upper interfaces and interval velocities are known too on account of the mathematical induction method applied. Thus, the zero‐offset reflection raypath of thenth interface can be supposed to be known down to the intersection with the (n—1)th interface.The method applied consists mainly in transforming the second power terms of the moveout time from one interface to the next one. This is accomplished by matrix algebra.Some special cases are discussed as e.g. uniform strike and small