The study of folded sedimentary layers such as these reveals that a given area was compressed, that the compressive forces came from a certain direction, and, by looking at the ages of rocks that are and are not deformed, the timing of the compressive event. Such data allow us to piece together the tectonic history of a region so that we can infer, for example, when a continental collision took place and what regional damage it caused.

Note that the layers in the interior of the fold are more complexly folded. This is because you run out of space as a fold closes, thus forcing the rocks in the center of a fold to accomodate the extra stresses.