horst

Diagram of horsts and grabens

In physical geography and geology, a horst is a raised fault block bounded by normal faults. Horsts are typically found together with grabens. While a horst is lifted or remains stationary, the grabens on either side subside. This is often caused by extensional forces pulling apart the crust. Horsts may represent features such as plateaus, mountains, or ridges on either side of a valley. Horsts can range in size from small fault blocks up to large regions of stable continent that have not been folded or warped by tectonic forces.