Transtension

Transtension is the state in which a rock mass or area of the Earth's crust experiences both extensive and transtensive shear. As such, transtensional regions are characterised by both extensional structures (normal faults, grabens) and wrench structures (strike-slip faults). In general, many tectonic regimes that were previously defined as simple strike-slip shear zones are actually transtensional. It is unlikely that a deforming body will experience 'pure' extension or 'pure' strike-slip.