Graben

In geology, a graben is a depressed block of land bordered by parallel faults. Graben is German for ditch or trench. The plural form is either graben or grabens.

A graben is a valley with a distinct escarpment on each side caused by the displacement of a block of land downward. Graben often occur side-by-side with horsts. Horst and graben structures indicate tensional forces and crustal stretching.

Graben are produced from parallel normal faults, where the displacement of the hanging wall is downward, while that of the footwall is upward. The faults typically dip toward the center of the graben from both sides. Horsts are parallel blocks that remain between graben; the bounding faults of a horst typically dip away from the center line of the horst.

Single or multiple graben can produce a rift valley.

Half-graben

In many rifts the graben are asymmetric, with a major fault along only one of the boundaries, and these are known as half-graben. The polarity (throw direction) of the main bounding faults typically alternate along the length of the rift. The asymmetry of a half-graben strongly affects syntectonic deposition. Comparatively little sediment enters the half-graben across the main bounding fault, due to the effects of footwall uplift on the drainage systems. The exception is at any major offset in the bounding fault, where a relay ramp may provide an important sediment input point. Most of the sediment will enter the half-graben down the unfaulted hanging wall side (e.g. Lake Baikal).

Graben, Switzerland

Graben is a municipality in the Oberaargau administrative district in the canton of Bern in Switzerland.

History

Graben is first mentioned in 1220 as Stadonce. In the 19th Century it was known as Graben durch den Wald.

Geography

Graben has an area, as of 2009, of 3.16 km² (1.22 sq mi). Of this area, 1.67 km² (0.64 sq mi) or 52.8% is used for agricultural purposes, while 1.16 km² (0.45 sq mi) or 36.7% is forested. Of the rest of the land, 0.22 km² (0.085 sq mi) or 7.0% is settled (buildings or roads), 0.11 km² (27 acres) or 3.5% is either rivers or lakes and 0.01 km² (2.5 acres) or 0.3% is unproductive land.

Of the built up area, housing and buildings made up 4.7% and transportation infrastructure made up 1.9%. 33.9% of the total land area is heavily forested and 2.8% is covered with orchards or small clusters of trees. Of the agricultural land, 36.4% is used for growing crops and 16.1% is pastures. All the water in the municipality is in rivers and streams.

The municipality is located at the confluence of the Önz into the Aare river a nature reserve. It includes the hamlets of Baumgarten, Burach, Gsoll, Hubel, Kleinholz, Schörlishäusern, Schwendi and Stadönz.

Graben (disambiguation)

Graben (German for ditch) may refer to:

Places

People