Block faulting is a geological process where the Earth’s crust is broken into large, fault-bounded blocks that are displaced vertically relative to one another. This process is commonly associated with extensional tectonics, where the crust is being pulled apart, such as in the Basin and Range Province of the western United States. Block faulting plays a significant role in the formation of rift valleys and mountain ranges.
Source Wernicke, B. (1981). “Low-Angle Normal Faults in the Basin and Range Province: Nappe Tectonics in an Extending Orogen.” Nature, 291(5810), 645-648.