The 1879 Gansu earthquake occurred at about 04:00 local time on 1 July. It had an estimated magnitude of 8.0 on the scale and a maximum perceived intensity of XI (''Extreme'') on the

Mercalli intensity scale The Modified Mercalli intensity scale (MM, MMI, or MCS) measures the effects of an earthquake at a given location. This is in contrast with the seismic magnitude usually reported for an earthquake. Magnitude scales measure the inherent force or ...

. The

epicenter The epicenter (), epicentre, or epicentrum in seismology is the point on the Earth's surface directly above a hypocenter or focus, the point where an earthquake or an underground explosion originates. Determination The primary purpose of a ...

was in

Wudu District Wudu District () is a district and the political and cultural center of Longnan, Gansu province, China. It borders the provinces of Shaanxi province and Sichuan to the southeast. It has a population of 546,616 as of the 2020 census, of which a po ...

in southern

Gansu Gansu is a provinces of China, province in Northwestern China. Its capital and largest city is Lanzhou, in the southeastern part of the province. The seventh-largest administrative district by area at , Gansu lies between the Tibetan Plateau, Ti ...

, close to the border with

Sichuan Sichuan is a province in Southwestern China, occupying the Sichuan Basin and Tibetan Plateau—between the Jinsha River to the west, the Daba Mountains to the north, and the Yunnan–Guizhou Plateau to the south. Its capital city is Cheng ...

. It caused widespread damage and killed an estimated 22,000 people.

Tectonic setting

The area of the earthquake lies just to the north of the eastern end of the East Kunlun Fault, a major left-lateral

strike-slip In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

fault zone that forms the boundary between the Bayan Har block, to the south, and the Eastern Kunlun–Qaidam block to the north, two parts of the

Tibetan Plateau The Tibetan Plateau, also known as the Qinghai–Tibet Plateau or Qingzang Plateau, is a vast elevated plateau located at the intersection of Central Asia, Central, South Asia, South, and East Asia. Geographically, it is located to the north of H ...

. As a whole the Tibetan Plateau is spreading to the east. Where it reaches the

Sichuan Basin The Sichuan Basin (), formerly transliterated as the Szechwan Basin, sometimes called the Red Basin, is a lowland region in southwestern China. It is surrounded by mountains on all sides and is drained by the upper Yangtze River and its tributar ...

, which overlies the

Yangtze plate The Yangtze plate, also called the South China block or the South China subplate, comprises the bulk of southern China. It is separated on the east from the Okinawa plate by a rift that forms the Okinawa Trough which is a back-arc basin, on the ...

, a thick and less deformable part of the

lithosphere A lithosphere () is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust and the lithospheric mantle, the topmost portion of the upper mantle that behaves elastically on time ...

, a series of southwest–northeast trending

thrust fault A thrust fault is a break in the Earth's crust, across which older rocks are pushed above younger rocks. Thrust geometry and nomenclature Reverse faults A thrust fault is a type of reverse fault that has a dip of 45 degrees or less. I ...

s have formed, known collectively as the

Longmenshan Fault The Longmenshan Fault () is a thrust fault which runs along the base of the Longmen Mountains in Sichuan province in southwestern China. The strike of the fault plane is approximately NE. Motion on this fault is responsible for the uplift of t ...

, the rupture of which was responsible for the

2008 Sichuan earthquake An earthquake occurred in the province of Sichuan, China at 14:28:01 China Standard Time on May 12, 2008. Measuring at 8.0 (7.9–8.3 ), the earthquake's epicenter was located boxing the compass, west-northwest of Chengdu, the provincial ...

Earthquake

The earthquake was preceded by

foreshock A foreshock is an earthquake that occurs before a larger seismic eventthe mainshockand is related to it in both time and space. The designation of an earthquake as ''foreshock'', ''mainshock'' or aftershock is only possible after the full sequenc ...

s in the few days before the mainshock. The meizoseismal area extends 70 km in a WSW-ENE direction and is 30 km across. The earthquake may have been caused by movement on the WSW-ENE trending Fanjiaba-Linjiang Fault. This fault correlates well with a 30 km long lineament seen on satellite images. The similarly oriented Hanan-Daoqizi-Maopola fault zone has also been proposed as a likely candidate. A rupture extent of 190 km has been estimated for this earthquake with a slip of 7.2 m. The earthquake triggered many

landslide Landslides, also known as landslips, rockslips or rockslides, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, mudflows, shallow or deep-seated slope failures and debris flows. Landslides ...

s and caused the formation of several natural dams 40 to 120 m in height.

Damage

In Wudu city there were a total of 9,881 casualties, with many houses damaged and about half of the livestock killed. Large parts of the city walls were badly damaged and 60 temples were destroyed at Wanshou Hill. In Wenxian and the surrounding villages 10,792 people were killed. Many homes were destroyed and the city walls collapsed.

References

{{Earthquakes in China 1879 earthquakes Earthquakes in Gansu 1879 in China July 1879 1870s disasters in Asia 19th-century disasters in China

Tectonic setting

Earthquake

Damage

See also

References