Translations:Reflection seismology/9/en

At a reflection, traces become coherent in the sense that they come into phase with each other. In other words, at a reflection, the crests and troughs on adjacent traces give the appearance of fitting into one another. The arrival time of a reflection indicates the depth of the reflecting horizon below the surface, whereas the time differential (the so-called stepout time) in the arrivals of a given peak or trough at successive receiver positions gives information on the dip of the reflecting horizon. In favorable areas, it is possible to follow the same reflection over a distance much greater than that covered by the receiver spread for a single record. In such cases, interpreters place the records side by side. The reflection from the last trace of one record correlates with the first trace of the next record. Such correlation can be continued on successive records as long as the reflection persists.