Faults

**Fault** is a planar rupture of the Earth’s surface, where physical forces cause dislocation of the crust along the part of the break. They can be horizontal, vertical or prone at any angle. The movement of the slipping parts within create **hanging wall** (top part of the fault) and **footwall** (bottom part of the fault). **Normal** faults are the cause of the vertical squeezing, while the **reversed** ones are accomplished by horizontal forces, reacting to shortening or contraction of the crust. A **graben** represents a block which sank between to another faults. The opposite scenario is a **horst**, where a specific black is lifted up between two normal faults. Horizontal compression, freeing energy by rock movement linearly, is known as **strike-slip** fault.