Horst and graben

USGS image

In geology, horst and graben refer to regions that lie between normal faults and are either higher or lower than the area beyond the faults. A horst represents a block pushed upward by the faulting, and a graben is a block that has dropped due to the faulting. Horst and Graben are formed when normal fault of opposite dip occur in pair with parallel strike lines . Horst and Graben are always formed together. Graben are usually represented by low-lying areas such as rifts and river valleys whereas horsts represent the ridges standing between/on either side of these valleys.

The Condroz and Ardennes region of Wallonia are good examples of a succession of horsts and grabens.

See also