Editing Graben

{{short description|Depressed block of planetary crust bordered by parallel normal faults}}
{{Other uses}}
{{Use dmy dates|date=July 2022}}

[[Image:Fault-Horst-Graben.svg|thumb|upright=1.35|Diagram illustrating the structural relationship between grabens and horsts]]
[[Image:Graben Afar ASTER 20020327.jpg|upright=1.35|thumb|Infrared-enhanced satellite image of a graben in the [[Afar Triangle|Afar Depression]]]]

In [[geology]], a '''graben''' ({{IPAc-en|ˈ|g|r|ɑː|b|ən}}) is a [[depression (geology)|depressed]] block of the [[Crust (geology)|crust]] of a planet or moon, bordered by parallel [[normal fault]]s.

==Etymology==
''Graben'' is a [[loan word]] from [[German language|German]], meaning 'ditch' or 'trench'. The first known usage of the word in the geologic context was by [[Eduard Suess]] in 1883.<ref>{{oed|graben}}</ref> The plural form is either ''graben''<ref>[https://glossary.oilfield.slb.com/en/terms/g/graben Schlumberger Oilfield Glossary]</ref> or ''grabens''.<ref name = "horst-and-graben">{{cite encyclopedia
 | title = horst and graben
 | encyclopedia = [[Encyclopædia Britannica]]
 | url = https://www.britannica.com/EBchecked/topic/272443/horst-and-graben
 | access-date = 2012-11-15}}</ref>

==Formation==
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 [[Horst (geology)|horst]]s. Horst and graben structures indicate tensional forces and crustal stretching.

Graben are produced by sets of [[normal fault]]s that have parallel [[fault trace]]s, 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==
{{Main|Half-graben}}
[[File:Newark Basin Cross Section.jpg|thumb|The [[Newark Basin]], an early [[Mesozoic]] half-graben]]

In many [[rift (geology)|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 alternates 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 because 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]]).<ref>{{cite journal|last1=Hans Nelson|first1=C.|last2=Karabanov|first2=Evgeny B.|last3=Colman|first3=Steven M.|last4=Escutia|first4=Carlota|title=Tectonic and sediment supply control of deep rift lake turbidite systems: Lake Baikal, Russia|journal=Geology|date=1999|volume=27|issue=2|pages=163–166|doi=10.1130/0091-7613(1999)027<0163:TASSCO>2.3.CO;2|bibcode=1999Geo....27..163N}}</ref>

[[Image:Rima Ariadaeus-1.jpg|thumb|[[Rima Ariadaeus]] on the [[Moon]] is thought to be a graben. The lack of erosion on the Moon makes its structure with two parallel faults and the sunken block in between particularly obvious.]]

== Examples ==

===Africa===
* [[East African Rift]] Valley
* Lucapa Graben, [[Lunda Norte Province]], [[Angola]]

===Antarctica===
* [[Lambert Graben]], [[Antarctica]]

===Asia===
* [[Narmada River]] Valley, [[central India]]
* lower [[Godavari River]] Valley, [[southern India]]
* [[Baikal Rift Zone]], [[Siberia]], [[Russia]]
* Moma Graben, [[Sakha Republic]], Russia
* [[Büyük Menderes Graben]], [[Turkey]]
* [[Fossa Magna]], [[Honshu]], [[Japan]]
* [[Ariake Sea]] as part of the Unzen graben, [[Kyushu]], Japan 
* [[Beppu–Shimabara graben]], Kyushu, Japan

===Europe===
* [[Upper Rhine Plain|Rhine valley]], border area of west [[Germany]] and northeast [[France]] 
* [[Oslo graben]] around [[Oslo]], [[Norway]]
* [[Central Lowlands]], [[Scotland]]
* [[Worcester Basin]], England
* Central Graben, [[North Sea]]
* Viking Graben, North Sea
* [[Vättern]], [[Sweden]]
* Lowtherville Graben, [[Ventnor]], [[Isle of Wight]], England<ref>{{Cite thesis |title=The Progressive Development and Post-failure Behaviour of Deep-seated Landslide Complexes |url=http://etheses.dur.ac.uk/3186/ |publisher=Durham University |date=2011 |degree=Doctoral |first=JONATHAN |last=CAREY}}</ref><ref>{{Cite journal |last=Carey |first=Jonathan |date=November 2014 |title=Patterns of movement in the Ventnor landslide complex, Isle of Wight, southern England |url=https://www.researchgate.net/publication/284942330 |journal=Landslides|volume=12 |issue=6 |page=1107 |doi=10.1007/s10346-014-0538-1 |bibcode=2015Lands..12.1107C }}</ref>

===North America===
====Canada====
* [[Ottawa-Bonnechere Graben]], [[Ontario]] and Quebec, Canada
* [[Saguenay Graben]], [[Quebec]], [[Canada]]

====Guatemala====
* [[Guatemala City]] valley, [[Guatemala]]

====United States====
* [[Basin and Range Province]] of southwestern [[North America]] is an example of multiple horst/graben structures, including [[Death Valley]], with [[Salt Lake Valley]] being the easternmost and [[Owens Valley]] being the westernmost.
* [[Lake George (town), New York|Lake George Basin]], New York, U.S.
* [[Lake Tahoe Basin]], [[California]] and [[Nevada]], U.S.
* [[Republic Graben]], Republic, [[Washington (state)|Washington]], U.S.
* [[Rio Grande Rift]] Valley in [[Colorado]]/[[New Mexico]]/[[Texas]] of the United States
* Rough Creek Graben, [[Kentucky]], U.S.
* [[Santa Clara Valley]], [[California]], U.S.
* Western [[Snake River Plain]], [[Idaho]], U.S.
* Southwest [[San Bernardino Valley (Arizona)]], U.S.

====Multi-national====
* [[Eastern North America Rift Basins]], Canada and the U.S.
* [[Midcontinent Rift System]], Canada and the U.S.
* [[Salton Trough]], Mexico and the U.S.

===Oceania===
* [[Firth of Thames]] of [[Hauraki Gulf]] and [[Hauraki Plains]] of [[Hauraki Rift]] (Hauraki half grabens), [[North Island]], [[New Zealand]]<ref>{{Cite journal|doi = 10.1080/00288306.1979.10422550|title = Geophysical study of the Hauraki Depression, North Island, New Zealand|year = 1979|last1 = Hochstein|first1 = M.P.|last2 = Nixon|first2 = I.M.|journal = New Zealand Journal of Geology and Geophysics|volume = 22| issue=1 |pages = 1–19|doi-access = free| bibcode=1979NZJGG..22....1H }}</ref>
* [[Tikitere Graben]] within the [[Taupō Rift]], North Island, New Zealand.<ref name="Manville2007">{{cite journal|first1= V. |last1=Manville |first2= K. A. |last2=Hodgson |first3=I. A. |last3=Nairn |year=2007 |title=A review of break-out floods from volcanogenic lakes in New Zealand |journal= New Zealand Journal of Geology and Geophysics|volume=50 |issue=2 |pages=131–150 |doi=10.1080/00288300709509826 |s2cid=129792354 |doi-access=free |bibcode=2007NZJGG..50..131M }}</ref>
* [[Gulf St Vincent]], [[South Australia]], [[Australia]]<ref name="Sprigg1961">{{cite journal | url=http://www.publish.csiro.au/AJ/AJ60011 | title=The Oil and Gas Prospects of the St. Vincents Gulf Graben | last=Sprigg | first=R.C. | journal=The APPEA Journal | year=1961 | volume=1 | issue=1 | pages=71–88 | doi=10.1071/AJ60011| url-access=subscription }}</ref>
* [[Tamar Valley, Tasmania|Tamar Valley]], [[Tasmania]], Australia<ref>Stacey, A. R., and Berry, R. F., (2004). "[http://www.mrt.tas.gov.au/mrtdoc/tasxplor/download/05_5109/StructuralHistoryOfTasmana.pdf The Structural history of Tasmania: a review for petroleum explorers]", PESA Eastern Australasian Basins Symposium II</ref>

===South America===
* [[Guanabara Bay|Guanabara Graben]], [[Rio de Janeiro]], [[Brazil]]

==See also==
*[[European Cenozoic Rift System]]
*{{annotated link|Fossa (geology)}}

==Notes==
{{Reflist}}

==References==
{{refbegin}}
* {{cite book | author1=McKnight, Tom L | author2=Hess, Darrel | year=2000 | chapter=The Internal Processes: Graben | title=Physical Geography: A Landscape Appreciation | pages=[https://archive.org/details/physicalgeographmckn/page/417 417] | location=Upper Saddle River, NJ | publisher=Prentice Hall | isbn=0-13-020263-0 | chapter-url-access=registration | chapter-url=https://archive.org/details/physicalgeographmckn/page/417 }}
{{refend}}

{{Structural geology}}

{{Authority control}}

[[Category:Structural geology]]
[[Category:Rifts and grabens| ]]
[[Category:Tectonic landforms]]