en>Rgdboer: /* Discussion */ re motions of elliptic space

2013-04-28T19:47:33Z

Discussion: re motions of elliptic space

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{{Use dmy dates|date=September 2011}}
The '''Chaman Fault''' is a major, active [[Fault (geology)|geological fault]] in Pakistan and [[Afghanistan]] that runs for over 850 km.<ref name="USGS-1">[http://www.usgs.gov/newsroom/article.asp?ID=1685 "USGS Unveils How Earthquakes Pose Risks to Afghanistan"] News Release, 30 May 2007, United States Geological Survey</ref> [[Plate tectonics|Tectonically]], it is actually a system of related geologic faults that separates the [[Eurasian Plate]] from the [[Indo-Australian Plate]]. It is a terrestrial, primarily [[Transform fault|transform]], [[Sinistral and dextral|left-lateral]] strike-slip fault. The slippage rate along the Chaman fault system as the Indo-Australian Plate moves northward (relative to the Eurasian Plate) has been estimated at 10 mm/yr or more.<ref name="USGS-1"/> In addition to its primary transform aspect, the Chaman fault system has a [[Convergent boundary|compressional component]] as the [[Indian Plate]] is colliding with the Eurasian Plate. This type of plate boundary is sometimes called a transpressional boundary.<ref name="USGS-2">[http://pubs.usgs.gov/fs/2007/3027/pdf/FS07-3027_508.pdf "Earthquakes Pose a Serious Hazard in Afghanistan"] Fact Sheet 2007–3027, April 2007, United States Geological Survey</ref>

From the south, the Chaman fault starts at the [[triple junction]] where the [[Arabian Plate]], the [[Eurasian Plate]] and the [[Indo-Australian Plate]] meet, which is just off the [[Makran|Makran Coast]] of Pakistan. The fault tracks northeast across [[Balochistan (Pakistan)|Balochistan]] and then north-northeast into Afghanistan, runs just to the west of [[Kabul]], and then northeastward across the right-lateral-slip Herat fault, up to where it merges with the Pamir fault system north of the 38º parallel.<ref>Fig.2 Chaman fault System associated with Indian Plate Boundary (April 2008) [http://www.neduet.edu.pk/Civil/2008-1.pdf "Chaman Fault System (CFS) – a Prominent Seismo-tectonic Feature In Pakistan"] ''Cowasjee Earthquake Study Centre Ned Newsletter'' 8(1): pp. 2–3, p.2</ref> The Ghazaband and Ornach-Nal faults are often included as part of the Chaman fault system. South of the triple junction, where the fault zone lies undersea and extends southwest to approximately 10ºN 57ºE, it is known as the [[Owen Fracture Zone]].

While there is general agreement that the fault is slipping at a rate of at least 10 mm/yr, there is a report of volcanic rocks in Pakistan dated to 2 m.y. BP which have been offset such as to indicate a slip rate of 25–35 mm/yr.<ref>not viewed, cited by Lawrence , R. D.; Khan, S. Hasan and Nakata, T. (1992) "Chaman fault, Pakistan-Afghanistan" ''In'' Bucknam, R. C. and Hancock, P. L. (eds.) (1992) ''Major active faults of the world—Results of IGCP project 206'' ''Annales Tectonicae'' 6(supplement): pp. 196–223</ref> Offsets have been described throughout the fault in Pakistan that are young enough that “only the alluvium of the bottom of active dry washes is not displaced.”<ref>Lawrence, R. D.; Khan, S. Hasan and Nakata, T. (1992) "Chaman fault, Pakistan-Afghanistan" ''In'' Bucknam, R. C. and Hancock, P. L. (eds.) (1992) ''Major active faults of the world—Results of IGCP project 206'' ''Annales Tectonicae'' 6(supplement): pp. 196–223, p. 204</ref>

The parallel mountain ranges of eastern Balochistan, (east to west) the [[Kirthar Mountains]], the Khude Mountains, the Zarro Mountains, the Pab Mountains and the Mor Mountains, are a result of the compressional plate boundary and are aligned parallel to the Chaman fault movement. The fault itself is west of these ranges.

==Significant earthquakes along the fault==
*1505, 5 July or 6th – An earthquake created a 60 km long surface rupture along a transverse fault in the Chaman system with several meters of vertical offset. This transverse fault is sometimes called the Paghman fault.<ref name="Quittmeyer">Quittmeyer, R. C. and Jacob, K. H.(1979) "Historical and modern seismicity of Pakistan, Afghanistan, northwestern India, and southeastern Iran" ''Bulletin of the Seismological Society of America'' 69: pp. 773–823, p.791</ref>
*1892, 20 December –<ref name="Quittmeyer"/><ref name="Wheeler">Wheeler, Russell L.; Bufe, Charles G.; Johnson, Margo L. and Dart, Richard L. (2005) [http://pubs.usgs.gov/of/2005/1264/pdf/OFR-1264.pdf "Seismotectonic map of Afghanistan, with annotated bibliography"] U.S. Geological Survey Open-File Report 2005-1264, p.9</ref>
*1935, 31 May – The 7.7 [[Moment magnitude scale|<math>M_\mathrm{w}</math>]] [[1935 Balochistan earthquake]] along the Ghazaband portion of the fault system killed upwards of 35,000 people.<ref>Carayannis, George Pararas (2007) [http://www.drgeorgepc.com/Earthquake1935PakistanQuetta.html "The Earthquake of 30 May 1935 in Quetta, Balochistan"]</ref>
*1978, 16 March – A 6.4 <math>M_\mathrm{w}</math> earthquake created a 5 km long rupture with up to 4 cm of left-lateral offset, and a smaller amount of vertical slip as the eastern wall of the fault dropped down.<ref>Yeats, R. S.; Lawrence, R. D.; Jamil-Ud-Din, Syed and Khan, S. H. (1979) "Surface effects of the 16 March 1978 earthquake, Pakistan-Afghanistan border" ''In'' Farah, Abul and DeJong, Kees A. (eds.) (1979) ''Geodynamics of Pakistan'' Geological Survey of Pakistan, Quetta, pp. 359–361</ref>

==See also==
* [[2008 Pakistan earthquake]]
* [[2013 Pakistan earthquake]]

==Notes==
{{reflist}}

==External links==
* [http://kagi.coe21.kyoto-u.ac.jp/en/tidbit/tidbit17.html Photograph of the surface expression of the Chaman fault] by Hiroyuki Tsutsumi

[[Category:Plate tectonics]]
[[Category:Geology of Pakistan]]
[[Category:Seismic faults of Asia]]
[[Category:Strike-slip faults]]

Quaternionic analysis - Revision history

en>Rgdboer: /* Discussion */ re motions of elliptic space