For the purpose of enhancing the efficiency of analytical processes so that those not equipped with high skill may perform a certain level of analysis and that analysis precision may be improved, some analytical techniques based on path calculation were examined. As the result, a flow of work has become feasible, wherein an early model is constructed by use of a tomography-assisted analysis to be accomplished automatedly and the result is then converted into a layer system with the velocity and thickness to be automatically corrected for the determination of the ultimate velocity layer section. Following this flow of work, almost all the parts of the work may be accomplished automatically once the travel time curve is completed. Furthermore, the calculated travel time obtained by this method can be easily compared with the observed travel time creating an opportunity to show the high reliability of this method, for this to be accepted as a standard for evaluating the accuracy of exploration. It has also been found that this method may be applied to more complicated structures which fail to satisfy the conditions for a structure to be treated by other methods such as `Hagiwara`s method.` 3 refs., 5 figs.