Major left-lateral strike-slip structures occur in the Tibetan Plateau as a result of the India–Asia collision.[4] These faults, including the Altyn Tagh, Haiyuan, Kunlun, Karakoram and Xianshuihe faults, accommodate crustal deformation within the Tibetan Plateau. One of these fault systems, the Haiyuan Fault, runs 1,000 km (620 mi) along the plateau's northeastern edge.[5]
The earthquake hit at 19:05:53Gansu-Sichuan time (12:05:53UTC),[6] reportedly 8.25Mw[7] or 7.8ML, and was followed by a series ofaftershocks for three years. The often cited magnitude in scientific literature is M 8.5 which has been regarded as an overestimate due to the limited technological advancements and instrumentation during the period which the earthquake occurred. On the moment magnitude scale which measures an earthquake with respect to its physical parameters, it is estimated at Mw 7.9.[8] The International Seismological Centre also catalogs the earthquake at Mw 7.9.[9]
About 230 km (140 mi) of surface faulting was seen from Lijunbu through Ganyanchi toJingtai. There were over 50,000 landslides in the epicentral area and ground cracking was widespread. Some rivers weredammed; others changed course.[10]Seiches from this earthquake were observed in two lakes and three fjords inwestern Norway.[3]
Field observations in the 1980s found 237 km (147 mi) of surface rupture along theHaiyuan Fault with a maximum horizontal offset of 6.5 m (21 ft) in the middle section of the rupture zone. The earthquake ruptured the section of the Haiyuan Fault between the Laohushan segment in the west and Liupanshan Thrust Fault to the east. The earthquake's epicenter is also likely nearHaiyuan which is supported by the seismic intensity distribution.[4]
Since 2003,[11] Chinese seismologists have calculated 258,707~273,407 to be the empirical verifiable range of death toll.[2] Older sources put the deaths to be 234,117[12] or 235,502.[13] Either way, it is one of the most fatalearthquakes in China, in turn making it one of the worstdisasters in China by death toll.
Many more perished because of cold: frequent aftershocks caused the survivors to fear building anything other than temporary shelters, and a severe winter killed many who had lived through the original earthquake.[14]
The SufiJahriyya MuslimHui leaderMa Yuanzhang and his son died in the earthquake when the roof of the Mosque they were in collapsed inZhangjiachuan.[15][16] Some of the first responders to the worst-hit towns, such asGuyuan, were soldiers from the Chinese military garrison commanded by Lu Hongtao at nearbyPingliang who arrived within days, bringing in tents and relief goods and evacuating the wounded back toPingliang by cart. Soup kitchens were also set up by gentry, merchants and other members of Guyuan’s community to serve the needy until transportation routes were restored and the markets were replenished. In other stricken communities, such asJingning, tents and emergency relief were provided by the magistrate working out of the county government office.[17]The Muslim GeneralMa Fuxiang was involved in relief efforts inLanzhou during the earthquake.[18][19][20]
^Han, Longfei; Liu-Zeng, Jing; Yao, Wenqian; Shao, Yanxiu; Yuan, Zhaode; Wang, Yan (November 2021). "Coseismic slip gradient at the western terminus of the 1920 Haiyuan Mw 7.9 earthquake".Journal of Structural Geology.152 104442.doi:10.1016/j.jsg.2021.104442.
^National Geophysical Data Center / World Data Service (NGDC/WDS): NCEI/WDS Global Significant Earthquake Database. NOAA National Centers for Environmental Information. (1972)."Significant earthquake Information". NOAA National Centers for Environmental Information.doi:10.7289/V5TD9V7K. Retrieved2024-03-21.
^"海原断裂带强震发生概率的评估方"(PDF).地震学报: 1048,1050. 2014.Archived(PDF) from the original on 2021-05-24. Retrieved2021-05-24.本文直接采用1920年海原地震的矩震级Ｗ8.25
^Pierre Fuller (2022).Modern Erasures: Revolution, the Civilizing Mission, and the Shaping of China’s Past. Cambridge: Cambridge University Press. p. 52, 67, 222.ISBN978-1-316-51572-3.
Xu, Xiurong; Zhang, Zhenguo; Hu, Feng; Chen, Xiaofei (2019), "Dynamic Rupture Simulations of the 1920 Ms 8.5 Haiyuan Earthquake in China",Bulletin of the Seismological Society of America,109 (5):2009–2020,Bibcode:2019BuSSA.109.2009X,doi:10.1785/0120190061,S2CID203134903
Chapter 1: "Networks into China's Northwest"; Chapter 2: "New Culture Lenses onto Rural Life"; and Chapter 10: "Communal Memory" in Pierre Fuller (2022).Modern Erasures: Revolution, the Civilizing Mission, and the Shaping of China's Past. Cambridge: Cambridge University Press.ISBN978-1-316-51572-3
This article incorporatespublic domain material from websites or documents of theUnited States Geological Survey.