| Haiyuan Fault | |
|---|---|
| Location | Tibet |
| Country | China |
| Characteristics | |
| Length | 1,000 km (620 mi) |
| Tectonics | |
| Plate | Eurasian Plate |
| Status | Active |
| Earthquakes | ~174-374 AD, 1092 AD, 1920, 1927, 2022 |
| Type | sinistral strike-slip fault |
The Haiyuan Fault is a major active intracontinental strike-slip (sinistral) fault in Central Asia. [1]
The Haiyuan Fault forms part of the northeastern boundary of the Tibetan Plateau, which is an area of continental crust that has been thickened by the ongoing continental collision between the Indian Plate and the Eurasian Plate. The Haiyuan Fault extends for approximately 1,000 km (620 mi) from the central Qilian Shan in the west, to the Liupan Shan, in the east. It is one of the group of structures that accommodates the overall eastward spreading of the plateau, that also includes the Altyn Tagh Fault, Kunlun Fault and the Xianshuihe fault system. [2] [1]
It is characterized by left-lateral strike-slip motion along its length, the motion transits to thrust at the eastern end, accommodated by the Liupanshan Fault. The average slip rate along the Haiyuan Fault is 3.2–9 mm/yr. [3] [1]
The Tianzhu seismic gap is a 260 km (160 mi) long, unruptured segment on the western end of the fault. It has not seen any major earthquakes for the past 1,000 years and was identified as a seismic gap. It poses a high risk for the capacity of large earthquakes. [4] An earthquake recurrence period of roughly 1,000 years has been suggested, with the last earthquakes on that section dated at 1092 AD and 174 or 374 AD. Locking depth of the fault range from 7.1–21.8 km (4.4–13.5 mi). [1] [3]
At the western end of the 1920 earthquake surface rupture, and between the Tianzhu seismic gap (from 37.11° N, 103.68° E to 37.00° N, 104.15° E) lies a 30–40 km (19–25 mi) section of the fault that displays a phenomenon known as an aseismic creep at shallow depths. [5]
The fault was the source of two very large and destructive earthquakes in 1920 and 1927. Two events in 143 A.D. or 374 A.D. and in 1092 may have been large earthquakes with estimated magnitudes of 8.0 or higher. [6]
On the evening of December 16, 1920, a M7.8–8.5 earthquake struck Haiyuan County, killing over 270,000 people. Shaking intensity reached a maximum of XII (Extreme), the uppermost limit on the Modified Mercalli intensity scale. The fault ruptured for a length of nearly 237 km (147 mi) in this event. [7] Surface ruptures from the earthquake have been well documented and a maximum surface displacement of 10–11 m (33–36 ft) was recorded. [6]
A magnitude 7.7 quake struck Gansu Province on the morning of May 22, 1927, the earthquake occurred on a different segment from the one involved in the 1920 quake. This earthquake caused the deaths of more than 40,000 people, and 200,000 livestock. [2] It is thought to have been produced along a south-dipping thrust fault located north of the Haiyuan Fault strand. This fault has been interpreted to be a branch of the Haiyuan Fault at depth. [6]
On October 20, 1990, a Mw 5.8 earthquake ruptured a small section of the fault with a maximum China seismic intensity of VIII. Serious damage was reported along a 27 km (17 mi) section of the fault. The earthquake produced surface fissures and cracks. The ancient walls of Songshan collapsed. No formal geological investigation was conducted although it is believed to have produced a surface rupture for several kilometers. [6] One fatality was reported. [8]
The 1995 Yongden earthquake on July 21, a Mw 5.6 earthquake struck near Yongden County, northeast of Lanzhou. It left 14 people killed, 533 injured and 8,860 homeless. At least 11,704 homes were destroyed and a further 5,083 were extensively damaged. Serious damage occurred to road and agricultural infrastructures. Livestock and farmland were destroyed by landslides. [9] A maximum intensity of VII was evaluated. [10] The earthquake was the result of movement along a previously unmapped south–southwest dipping thrust fault. [11]
An Mw 6.6 or Ms 6.9 earthquake struck Menyuan County in January 2022, causing little damage and few minor injuries. [12] The earthquake was felt with a maximum intensity of IX on the China seismic intensity scale (IX on the Modified Mercalli intensity scale [13] ) over a 157 km3 area. [14]
It generated a 22 km (14 mi) surface rupture along the Lenglongling segment of the Haiyuan Fault. On-site investigations found up to 2.1 m (6 ft 11 in) of left-lateral strike-slip offsets. The surface rupture also crossed the tunnel of a high-speed railway linking Lanzhou to Ürümqi, causing severe damage to a bridge and the tracks. Modelling of the earthquake suggest it had a maximum coseisic slip of around 3.5 m (11 ft) at a depth of 0–10 km (0.0–6.2 mi) along the rupture. [13]
The 1920 Haiyuan earthquake occurred on December 16 in Haiyuan County, Ningxia Province, Republic of China at 19:05:53. It was also called the 1920 Gansu earthquake because Ningxia was a part of Gansu Province when the earthquake occurred. It caused destruction in the Lijunbu-Haiyuan-Ganyanchi area and was assigned the maximum intensity on the Mercalli intensity scale. About 258,707~273,407 died, making it one of the most fatal earthquakes in China, in turn making it one of the worst disasters in China by death toll.
An earthquake occurred in China on 14 November 2001 at 09:26 UTC, with an epicenter near Kokoxili, close to the border between Qinghai and Xinjiang in a remote mountainous region. With a magnitude of 7.8 Mw, it was the most powerful earthquake in China for 5 decades. No casualties were reported, presumably due to the very low population density and the lack of high-rise buildings. This earthquake was associated with the longest surface rupture ever recorded on land, ~450 km.
The 1927 Gulang earthquake occurred at 6:32 a.m. on 22 May. This 7.6 magnitude event had an epicenter near Gulang, Gansu in the Republic of China. There were 40,912 deaths. It was felt up to 700 km (435 mi) away.
The 1932 Changma earthquake occurred at 10:04:27 local time on 25 December. With an estimated magnitude of 7.6 on the surface wave magnitude scale, and a maximum felt intensity of X (Extreme) on the Mercalli intensity scale, the quake destroyed 1,167 houses and caused 275 to 70,000 deaths and 320 injuries.
The 1930 Pyu earthquake occurred on December 4 at 01:21 local time. The epicenter was located north to Bago, Burma, then part of British India. The magnitude of the earthquake was estimated at Mw 7.3, or Ms 7.3.
The Zhongwei-Tongxin fault or Tianjingshan fault is an arcuate sinistral (left-lateral) strike-slip zone, forming one of the major structures on the northeastern margin of Tibetan plateau. Six paleoearthquake events in the past 14,000 years have been recorded along the Zhongwei-Tongxin fault zone. Among the earthquakes recorded are the 1622 North Guyuan earthquake, which had a magnitude of 7.0 and mid-seismogenic depth of about 15 kilometres (9.3 mi), the 1709 Zhongwei earthquake, which had a magnitude of 7.5.
The 1988 Lancang–Gengma earthquakes, also known as the 11.6 earthquakes by the Chinese media were a pair of devastating seismic events that struck Lancang and Gengma counties, Yunnan, near the border with Shan State, Burma. The earthquake measured moment magnitude (Mw ) 7.0 and was followed 13 minutes later by a 6.9 Mw shock. These earthquakes were assigned a maximum China seismic intensity of IX and X, respectively. Between 748 and 939 people were killed; more than 7,700 were injured. Both earthquakes resulted in US$270 million in damage and economic losses. Moderately large aftershocks continued to rock the region, causing additional casualties and damage.
The 1973 Luhuo earthquake struck near the town of Zhaggo in Garzê Tibetan Autonomous Prefecture of Sichuan Province, China on February 6, 1973, with a magnitude of 7.6 Ms. The earthquake had a maximum intensity of X (Extreme) on the Modified Mercalli intensity scale. It resulted in between 2,175 and 2,204 deaths and a further 2,743 injuries. Serious and widespread destruction occurred in Luhuo County.
The 1739 Yinchuan–Pingluo earthquake rocked the northern Ningxia Hui Autonomous Region on January 3 with an epicenter in the prefecture-level city Shizuishan. The estimated magnitude 7.1–7.6 earthquake had a maximum intensity of XI on the Mercalli intensity scale, and killed about 50,000 residents and officials. It was widely felt; perceived in Shanxi, Shaanxi and Hebei provinces. Aftershocks persisted for more than two years with the largest being a 5.5 on February 13 that same year.
The 1902 Turkestan earthquake devastated Xinjiang, China, near the Kyrgyzstan border. It occurred on August 22, 1902, at 03:00:22 with an epicenter in the Tien Shan mountains. The thrust earthquake measured 7.7 on the moment magnitude scale (Mw ) and had a depth of 18 km (11 mi).
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. It measured 8.0–8.3 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 280–300 people died and another 1,000 more were injured by the earthquake.
The 2021 Maduo earthquake, also known as the 5.22 earthquake struck Madoi County in Qinghai Province, China on 22 May at 02:04 local time. The earthquake had a moment magnitude and surface-wave magnitude of 7.4. Highway bridges, roads and walls collapsed as a result of the earthquake. According to an anonymous source, at least 20 people were killed, 300 were injured, and 13 were missing. Officials stated that there were no deaths but 19 people sustained minor injuries. It was the strongest in China since 2008. It was assigned a maximum intensity of X in Machali, Maduo County on the China seismic intensity scale and Modified Mercalli intensity scale. This earthquake was preceded by another unrelated earthquake that occurred 5 hours earlier in Yunnan.
The 2020 Kashgar earthquake, also known as the Jiashi earthquake occurred on 19 January 2020 at 21:27:56 China Standard Time in Xinjiang Province, China. According to the United States Geological Survey, the earthquake had a moment magnitude of 6.0 and a surface wave magnitude of 6.4 according to the China Earthquake Network Center. It struck at a shallow depth of 5.6 km according to the USGS while the CENC has the figure at 16 km. Local emergency management agencies said the earthquake damaged more than 1,000 homes and businesses in the nearby populated towns and villages. One person is known to have died while two other children were injured.
The 1889 Chilik earthquake occurred on July 11 on the Gregorian calendar, or June 30 on the Julian calendar at 15:14 local time in the Tien Shan mountains. The earthquake measured an estimated Mw 7.9–8.0 on the moment magnitude scale and was assigned a maximum intensity of X (Devastating) on the MSK 64 and Rossi-Forel scales. Over 92 people across Kazakhstan, Kyrgyzstan and China were killed.
The 1695 Linfen earthquake struck Shanxi Province in North China, Qing dynasty on May 18. Occurring at a shallow depth within the continental crust, the surface-wave magnitude 7.8 earthquake had a maximum intensity of XI on the China seismic intensity scale and Mercalli intensity scale. This devastating earthquake affected over 120 counties across eight provinces of modern-day China. An estimated 52,600 people died in the earthquake, although the death toll may have been 176,365.
The 1850 Xichang earthquake rocked Sichuan Province of Qing China on September 12. The earthquake which caused major damage in Xichang county had an estimated moment magnitude of 7.6–7.9 Mw and a surface wave magnitude of 7.5–7.7 Ms . An estimated 20,650 people died.
The 1654 Tianshui earthquake occurred on July 21 in Tianshui, Gansu Province, Ming dynasty sometime between 21:00 and 23:00 local time. The event had an estimated moment magnitude of 7.0 and was assigned a maximum intensity of XI on the China seismic intensity scale. Resulting in extreme damage and affecting at least four provinces, the quake killed approximately 30,000 people.
The 1923 Renda earthquake occurred on March 24 at 20:40 local time between the counties of Daofu and Luhuo in Sichuan, China. The estimated Ms 7.3 earthquake was assigned a maximum modified Mercalli intensity scale rating of X (Extreme). Severe damage occurred in Sichuan, killing an estimated 4,800 people.
On January 8, 2022, a magnitude 6.6 earthquake struck Menyuan County, Qinghai Province near the border with Gansu Province, China. It was the largest earthquake in China since the 2021 Maduo earthquake.
The region of Ningxia was struck by a major earthquake on the morning of 14 October 1709. It had an estimated magnitude of 7.5 Ms and a maximum felt intensity of X (extreme) on the Modified Mercalli intensity scale. The city of Zhongwei was badly damaged, including a section of the Great Wall. A total of 2,032 people were killed.