1920 Haiyuan earthquake
|Date||December 16, 1920
|Magnitude||7.8 ML 8.5|
(Haiyuan, Ningxia Hui Autonimous Region)
|Areas affected||Republic of China|
|Max. intensity||XII (Catastrophic)|
|Casualties||273,400 (4th deadliest earthquake of all time)|
1920 Haiyuan earthquake (Chinese: 海原大地震; pinyin: Hǎiyuán dà dìzhèn) occurred on December 16 with an epicenter at , in Haiyuan County, Ningxia Province, Republic of China. It was also called the 1920 Gansu earthquake  because Ningxia was a part of Gansu Province when the earthquake occurred.
The earthquake hit at 20:05:53 Beijing time (12:05:53 UTC), reportedly 7.8 on the Richter magnitude scale, followed by a series of aftershocks for three years. Today's Chinese media claim the earthquake was of magnitude 8.5, although the scale is not specified. It caused total destruction (XII - the maximum intensity on the Mercalli scale) in the Lijunbu-Haiyuan-Ganyanchi area.
Over 73,000 people were killed in Haiyuan County. A landslide buried the village of Sujiahe in Xiji County. More than 30,000 people were killed in Guyuan County. Nearly all the houses collapsed in the cities of Longde and Huining. Damage (VI-X) occurred in 7 provinces and regions, including the major cities of Lanzhou, Taiyuan, Xi'an, Xining and Yinchuan. It was felt from the Yellow Sea to Qinghai (Tsinghai) Province and from Nei Mongol (Inner Mongolia) south to central Sichuan Province.
About 200 km (125 mi) of surface faulting was seen from Lijunbu through Ganyanchi to Jingtai. There were large numbers of landslides and ground cracks throughout the epicentral area. Some rivers were dammed, others changed course. Seiches from this earthquake were observed in 2 lakes and 3 fjords in western Norway.
Total casualties were reported as 200,000 in a summary published by the United States Geological Survey (USGS), 240,000 according to Ningxia Daily, a Chinese publication in the current administrative area, and 235,502 according to the Catalog of Damaging Earthquakes in the World (Through 2008) maintained by the International Institute of Seismology and Earthquake Engineering. 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.
- "Most Destructive Known Earthquakes on Record in the World". Earthquake.usgs.gov. Retrieved 2011-10-26.
- "10 Greatest Earthquakes in China in 20th Century" (in Chinese). Ningxia Daily website. 2008-05-15. Retrieved 2008-06-02.
- "Death Toll of 1920 China Earthquake Higher than Previously Estimated." English.news.cn. Xinhua, 16 Dec. 2010. Web. 27 Dec. 2012.
- "Significant earthquake". The Significant Earthquake Database. National Geophysical Data Center. Retrieved 2013-06-15.
- Close, Upton, and Elsie McCormick. "Where the Mountains Walked". National Geographic 41.5 (1922): 445-464: 451.