rift

thumb|Block view of a rift formed cut of three segments, showing the location of the accommodation zones between them at changes in fault location or polarity (dip direction). upright|thumb|Gulf of Suez Rift showing main [[extensional faults]]

In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben with normal faulting and rift-flank uplifts mainly on one side. Where rifts remain above sea level they form a rift valley, which may be filled by water forming a rift lake. The axis of the rift area may contain volcanic rocks, and active volcanism is a part of many, but not all, active rift systems.