earthquake An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, fr ...

occurred on 1 June 1786 in and around

Kangding Kangding (), also called Tachienlu and Dartsedo (; ), is a county-level city and the seat of Garzê Tibetan Autonomous Prefecture in Sichuan province of Southwest China. Kangding is on the bank of the Dadu River and has been considered the histor ...

, in what is now China's

Sichuan Sichuan (; zh, c=, labels=no, ; zh, p=Sìchuān; alternatively romanized as Szechuan or Szechwan; formerly also referred to as "West China" or "Western China" by Protestant missions) is a province in Southwest China occupying most of the ...

province. It had an estimated magnitude of about 7.75 and a maximum perceived intensity of X (''Extreme'') on the Mercalli intensity scale. The initial quake killed 435 people. After an aftershock ten days later, a further 100,000 died when a

landslide dam A landslide dam or barrier lake is the natural damming of a river by some kind of landslide, such as a debris flow, rock avalanche or volcanic eruption. If the damming landslide is caused by an earthquake, it may also be called a quake lake. Some ...

collapsed across the

Dadu river The Dadu River (), known in Tibetan as the Gyelmo Ngul Chu, is a major river located primarily in Sichuan province, southwestern China. The Dadu flows from the eastern Tibetan Plateau into the Sichuan Basin where it joins with the Min River, a t ...

Tectonic setting

Sichuan lies within the complex zone of deformation associated with the continuing

collision In physics, a collision is any event in which two or more bodies exert forces on each other in a relatively short time. Although the most common use of the word ''collision'' refers to incidents in which two or more objects collide with great fo ...

between the

India Plate The Indian Plate (or India Plate) is a minor tectonic plate straddling the equator in the Eastern Hemisphere. Originally a part of the ancient continent of Gondwana, the Indian Plate broke away from the other fragments of Gondwana , began mov ...

and the

Eurasian Plate The Eurasian Plate is a tectonic plate that includes most of the continent of Eurasia (a landmass consisting of the traditional continents of Europe and Asia), with the notable exceptions of the Indian subcontinent, the Arabian subcontinent and ...

. The thickened crust of the

Tibetan plateau The Tibetan Plateau (, also known as the Qinghai–Tibet Plateau or the Qing–Zang Plateau () or as the Himalayan Plateau in India, is a vast elevated plateau located at the intersection of Central, South and East Asia covering most of the ...

is spreading to the east causing the southward motion of the Sichuan-Yunnan block. The eastern side of this block is bounded by the

Xianshuihe fault system The Xianshuihe fault system is a major active sinistral (left-lateral) strike-slip fault zone in southwestern China, at the eastern edge of the Tibetan Plateau. It has been responsible for many major earthquakes, and is one of the most seismicall ...

, a major left lateral strike-slip fault zone. Movement on this fault zone has been responsible for many major damaging earthquakes, such as the 1981 Dawu earthquake.

Earthquake

isoseismal map In seismology, an isoseismal map is used to show lines of equally felt seismic intensity, generally measured on the Modified Mercalli scale. Such maps help to identify earthquake epicenters, particularly where no instrumental records exist, such a ...

constructed for this earthquake shows that the zone of maximum shaking was elongated in a northwest–southeast direction, parallel to the trace of the Xianshuihe Fault. The magnitude of 7.5–8.0 has been estimated from the extent of the intensity VIII (''Severe'') zone. Remote sensing techniques, backed up by a field survey, identified a long zone of surface fault rupture thought to be associated with the earthquake. The

active fault An active fault is a fault that is likely to become the source of another earthquake sometime in the future. Geologists commonly consider faults to be active if there has been movement observed or evidence of seismic activity during the last 10,0 ...

segment has been identified as the Moxi Fault.

Landslide dam

The earthquake triggered numerous landslides, one of which blocked the Dadu River, forming a temporary lake. The dam was about high, holding back an estimated water volume of about . By 9 June the lake had started to flow over the dam and an aftershock on 10 June caused the dam to collapse suddenly, releasing the impounded water and devastating areas downstream. It is the second-deadliest landslide disaster on record, after the

1920 Haiyuan earthquake 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 cau ...

.. p.66

Damage

The earthquake caused widespread damage in the epicentral area. The city walls at

collapsed and severe damage to many houses and government buildings caused 250 casualties. In

Luding County Luding County (), also known via its Tibetan name as Chagsam or Jagsam ) is a county located in the southeast of the Garzê Tibetan Autonomous Prefecture in Sichuan province, China. Luding County covers an area of , and has a population of 86,234 ...

181 people were killed in collapsed buildings. At both Qingxi and Yuexi, parts of the city walls were destroyed and many buildings were severely damaged, causing further casualties. The flood that resulted from the landslide dam failure reached the city of

Leshan Leshan, formerly known as Jiading or Jiazhou, is a prefecture-level city located at the confluence of the Dadu and Min rivers in Sichuan Province, China. Leshan is located on the southwestern fringe of the Sichuan Basin in southern Sichuan, abou ...

on 11 June, causing collapse of part of the city walls. Spectators who had gathered to watch the flood from the walls were thrown into the water. The destructive effects of the flood continued downstream at

Yibin Yibin (; Sichuanese Pinyin: nyi2bin1; Sichuanese pronunciation: ) is a prefecture-level city in the southeastern part of Sichuan province, China, located at the junction of the Min and Yangtze Rivers. Its population was 4,588,804 inhabitants, a ...

and Luzhou, with an estimated 100,000 people being killed overall. Local residents made a memorial tablet, describing these events, which is now kept at the Seismological Office in Luding.

References

{{Earthquakes in China Kangding-Luding earthquake Kangding-Luding earthquake Kangding-Luding earthquake 1786 in China Kangding

Tectonic setting

Earthquake

Landslide dam

Damage

See also

References