1906 Manasi earthquake

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1906 Manasi earthquake
1906 Manasi earthquake is located in China
1906 Manasi earthquake
UTC time1906-12-22 18:21:11
ISC event16957935
USGS-ANSSComCat
Local dateDecember 22, 1906 (1906-12-22)
MagnitudeMw 7.8–8.3
Depth20 km[1]
Epicenter44°17′02″N 85°34′19″E / 44.284°N 85.572°E / 44.284; 85.572
TypeBlind thrust
Max. intensityX (Extreme)
Casualties280+ dead[2]

The 1906 Manasi earthquake (玛纳斯地震), also known as the Manas earthquake occurred in the morning of December 23, 1906, at 02:21 UTC+8:00 local time or December 22, 18:21 UTC. Its estimated magnitude was 7.9–8.3 on the moment magnitude scale and 8.3 on the surface-wave magnitude scale. The epicenter of this earthquake is located in Manas County, Xinjiang, China. An estimated 280 to 300 people died and another 1,000 more were injured by the earthquake.

Tectonic setting[]

The Tien Shan mountains in Central Asia formed as a result of the thrusting and folding of continental crust during the Late Cenozoic era. Around this time, the Indian subcontinent is colliding with Asia along a 2,500 km long convergent boundary known as the Main Himalayan Thrust. The ongoing collision of India into the Eurasian Plate has resulted in extreme internal deformation of the continental crust. Deformation has induced large-scale intraplate shear and thrust faulting far from the plate boundary. Thrusting along the Tien Shan mountains has shortened the crust by an average velocity of 13±7 mm/yr.[3] In some areas such as the Western Tien Shan, the shortening rate is as high as 23 mm/yr, however in the northern region, that rate is much slower at just 6 mm/yr.[1]

Earthquake[]

The earthquake occurred as a result of thrust faulting within the fold and thrust belt beneath the northern flanks of the Tien Shan range. Specifically, it occurred on the Huoerguosi‐Manas‐Tugulu Fault, a 45° south-dipping thrust fault that becomes a detachment fault, and later a steep reverse structure as it dips further down beneath the Borohoro Mountains, a subrange of the Tien Shan.[4] Research suggests that the Manasi earthquake had a 150 km by 75 km rupture area and an average fault slip of 3.5 ± 2 meters at depth. This would correspond to a moment magnitude in the range 7.8 to 8.3, the most plausible magnitude for the event.[3] The earthquake's focal depth is not well known due to the lack of local seismic instrumentation at the time, values from Chinese earthquake catalogues give a range from 12 to 30 km depth. An analysis of focal depths for other earthquakes in the area published in 2004 obtained an average figure of 20 km, therefore the 1906 earthquake likely nucleated at this depth.[1] The same research also proposed that the earthquake rupture initiated on the steep reverse fault and later onto the detachment.[1]

Although this was a blind thrust earthquake, surface scarps were produced. The deep blind reverse fault responsible for the rupture triggered small surface scarps with heights 0.2–0.5 meters to form at the surface.[5] These surface breaks are associated with the Huoerguosi‐Manas‐Tugulu fold and anticline zone, believed to be the source of the earthquake at depth. During the deep earthquake rupture process, the fold and anticline zone began picking up motions, resulting in a surface rupture.[5] In addition to the surface scarps, zones of uplift and folding were also observed 45 km away from the epicenter.[1]

Impact[]

The earthquake had a maximum intensity of X (Extreme) on the Mercalli intensity scale.[1] In the villages of Shizijie, Bajiahu, Niujuanzi, Zhuanglangmiao, Xidatang, Shichang, in Boluotonggu, and the mountain areas around Dazimiao and Reshuiquanzi, many wood and mud houses collapsed while those that remained intact were tilted.[2] More than 2,000 homes were destroyed, resulting in more than 280 people dying. Many temples were also completely destroyed. Surface fissures tore through the ground, ranging from 0.2 meters to one meter wide, and up to several kilometers long. The earthquake also triggered landslides and opened wide cracks near the mountains.[2] The earthquake also caused slumping channel banks some 5 to 15 km long.[2]

In Shawan County, an estimated 30% of all residential infrastructures collapsed but there were no fatalities. The nearby city of Changji reported some damage to its temples during the shaking. In Wusu, many homes constructed of mud and wooden beams also collapsed. The walls of some old homes cracked as a result of the earthquake.[2]

See also[]

References[]

  1. ^ Jump up to: a b c d e f Chun-Yong Wang, Zhu-En Yang, Hai Luo, W.D. Mooney (2004). "Crustal structure of the northern margin of the eastern Tien Shan, China, and its tectonic implications for the 1906 M~7.7 Manas earthquake" (PDF). Earth and Planetary Science Letters. 223 (1–2): 187–202. Bibcode:2004E&PSL.223..187W. doi:10.1016/j.epsl.2004.04.015. ISSN 0012-821X.CS1 maint: multiple names: authors list (link)
  2. ^ Jump up to: a b c d e "CHINA: XINJIANG PROVINCE". NGDC NCEI. NCEI. Retrieved 17 March 2021.
  3. ^ Jump up to: a b J. P. Avouac P. Tapponnier M. Bai H. You G. Wang (10 April 1993). "Active Thrusting and Folding Along the Northern Tien Shan and Late Cenozoic Rotation of the Tarim Relative to Dzungaria and Kazakhstan". Journal of Geophysical Research: Solid Earth. 98 (B4): 6755–6804. Bibcode:1993JGR....98.6755A. doi:10.1029/92JB01963. Retrieved 17 March 2021.
  4. ^ Xiaohang Wang, Caijun Xu, Yangmao Wen, Shuai Wang, Guangyu Xu, Zhuohui Xiao, Lihua Fang (2019). "The 2016 Mw 6.0 Hutubi earthquake: A blind thrust event along the northern Tian Shan front". Journal of Asian Earth Sciences. 173: 79–87. Bibcode:2019JAESc.173...79W. doi:10.1016/j.jseaes.2019.01.011. ISSN 1367-9120.CS1 maint: multiple names: authors list (link)
  5. ^ Jump up to: a b Ying‐Hui Yang, Jyr‐Ching Hu, Qiang Chen, Ze‐Gen Wang, Min‐Chien Tsai (2019). "A Blind Thrust and Overlying Folding Earthquake of the 2016 Mw 6.0 Hutubi Earthquake in the Northern Tien Shan Fold‐and‐Thrust Belts, China". Bulletin of the Seismological Society of America. 109 (2): 770–779. Bibcode:2019BuSSA.109..770Y. doi:10.1785/0120180150.CS1 maint: multiple names: authors list (link)
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