Faulting, Folding, and Intruding

A fault is defined as a planar or gently curved fracture in the earth's crust across which there has beenrelative displacement of the two blocks of rock parallel to the fracture. There are four basic types of fault: Normal, Reverse, Thrust, and Transition (also known as Strike-Slip).

Normal Fault - The footwall moves upward relative to the hanging wall.	Reverse Fault - The hanging wall moves upward relative to the footwall.	Thrust Fault - A low-angle reverse fault.	Transition Fault - A fault in which movement is lateral.

A fold is defined as a bent or warped stratum or sequence of strata that was originally horizontal, or nearly so, and was subsequently deformed.

An intrusion is defined as an igneous rock that has forced its way, in a molten state, into the country rock of an area.