View source for Bayan Har block

[[File:TibetanPlateauTectonics.png|thumb|300px|Tectonic map of the Tibetan Plateau showing the main structures]]
The '''Bayan Har block''' or '''Bayan Kola block''' is an elongate wedge-shaped block that forms part of the eastern [[Tibetan Plateau]]. It is bounded to the southeast by the [[Longmenshan Fault]], a major [[thrust fault]] zone, which forms the active tectonic boundary between the plateau and the [[Sichuan Basin]]. To the northeast, the boundary is formed by the [[Kunlun Fault|Kunlun]] and [[Minjiang Fault]]s juxtaposing the block against the Eastern Kunlun-Qaidam block<ref name="Wang_etal_2017">{{Cite journal |last1=Wang |first1=J. |last2=Xu |first2=C. |last3=Freymueller |first3=J.T. |last4=Li |first4=Z. |date=2017 |title=Probing Coulomb stress triggering effects for a Mw > 6.0 earthquake sequence from 1997 to 2014 along the periphery of the Bayan Har block on the Tibetan Plateau |journal=Tectonophysics |volume=694 |pages=249–267 |doi=10.1016/j.tecto.2016.11.009|bibcode=2017Tectp.694..249W |doi-access=free }}</ref> and to the southwest by the [[Xianshuihe fault system]] forms its boundary with the Qiangtang block.<ref name="Xu_etal_2015">{{Cite journal |last1=Xu |first1=C. |last2=Xu |first2=X. |last3=Shyu |first3=J.B.H. |last4=Gao |first4=M. |last5=Tan |first5=X. |last6=Ran |first6=Y. |last7=Zheng |first7=W. |date=2015 |title=Landslides triggered by the 20 April 2013 Lushan, China, Mw 6.6 earthquake from field investigations and preliminary analyses |journal=Landslides |volume=12 |issue=2 |pages=365–385 |doi= 10.1007/s10346-014-0546-1|s2cid=129486468 }}</ref> All of these are major left-lateral [[strike-slip]] fault zones. The block is currently moving to the southeast relative to the [[South China block]].<ref name="Xu_etal_2008">{{Cite journal |last1=Xu |first1=X.W. |last2=Wen |first2=X.Z. |last3=Chen |first3=G.H. |last4=Yu |first4=G.H. |date=2008 |title=Discovery of the Longriba Fault Zone in Eastern Bayan Har Block, China and its tectonic implication |url=https://www.researchgate.net/publication/226744920 |journal=Science in China Series D: Earth Sciences |volume=51 |issue=9 |pages=1209–1223|doi=10.1007/s11430-008-0097-1 |bibcode=2008ScChD..51.1209X |s2cid=128682470 }}</ref><ref name="Sun_etal_2015">{{cite journal |last1=Yujun Sun, Taoyuan Fan, Chunjing Zhou, Zhonghai Wu |title=The Evolution of Stress and Strain around the Bayan Har Block in the Tibetan Plateau |journal=Journal of Earthquakes |date=2015 |volume=2015 |pages=10 |doi=10.1155/2015/971628 |id=971628|doi-access=free }}</ref>
==Internal deformation==
The southeastern part of the block, known as the Longmenshan sub-block, accommodates a significant part of its eastward motion. The northwestern boundary of this sub-block is formed by the parallel Longriba and Maoergai faults, with the former showing evidence of mainly thrusting to the southeast and the latter showing a significant component of right lateral strike-slip. The NW-SE shortening within the sub-block is caused by the resistance offered by the stronger [[lithosphere]] of the South China Block, which has led to a backwards propagating thrust system.<ref name="Xu_etal_2008">{{Cite journal |last1=Xu |first1=X.W. |last2=Wen |first2=X.Z. |last3=Chen |first3=G.H. |last4=Yu |first4=G.H. |date=2008 |title=Discovery of the Longriba Fault Zone in Eastern Bayan Har Block, China and its tectonic implication |url=https://www.researchgate.net/publication/226744920 |journal=Science in China Series D: Earth Sciences |volume=51 |issue=9 |pages=1209–1223|doi=10.1007/s11430-008-0097-1 |bibcode=2008ScChD..51.1209X |s2cid=128682470 }}</ref> The area between the Longriba and Longmenshan faults has a current uplift rate of 1.5 mm per year. This model is consistent with observations of increased slip rates on the more southeasterly parts of the Xianshuihe fault system.<ref name="Qiao_etal_2022">{{Cite journal |last=Qiao |first=X. |last2=Zhou |first2=Y. |last3=Zhang |first3=P. |date=2022 |title=Along-strike variation in fault structural maturity and seismic moment deficits on the Yushu-Ganzi-Xianshuihe fault system revealed by strain accumulation and regional seismicity |journal=Earth and Planetary Science Letters |volume=596 |doi=10.1016/j.epsl.2022.117799}}</ref>
==Seismicity==
Earthquakes are mainly concentrated on the faults bounding the block, such as the [[2001 Kunlun earthquake]] (on the Kunlun Fault), the [[2008 Sichuan earthquake]] (on the Longmenshan Fault) and the [[1973 Luhuo earthquake]], [[1981 Dawu earthquake]] and [[2010 Yushu earthquake]] (all on the Xianshuihe fault system).<ref name="Wang_etal_2017"/> In May 2021, the block hosted the [[2021 Maduo earthquake|Maduo earthquake]]; upon further analysis, found that the [[intraplate earthquake]] occurred on a fault within the block.<ref name="Zhiyu">{{cite journal |author1=Zhiyu Gao |author2=Yanchuan Li |author3=Xinjian Shan |author4=Chuanhua Zhu |title=Earthquake Magnitude Estimation from High-rate GNSS Data: A Case Study of the 2021 Mw 7.3 Maduo Earthquake |journal=Remote Sensing |date=8 November 2021 |volume=13 |issue=4478 |page=4478 |doi=10.3390/rs13214478|bibcode=2021RemS...13.4478G |doi-access=free }}</ref>
==References==
{{Reflist}}
[[Category:Geology of China]]
[[Category:Tibetan Plateau]]