When rocks are subject to tectonic stresses, caused by events such as the collision of continents, they will be deformed into folds and faults. Trough-shaped folds are termed synclines and
arch-shaped folds are termed anticlines. In the Isle of Man, these folds can vary in size from only a few centimetres to several kilometres in width.

Different types of faults develop according to whether rocks are being compressed
(reverse and thrust faults) or stretched (normal faults).