The Xianshuihe fault system is a major active sinistral (left-lateral)

strike-slip fault 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 ...

zone in southwestern China, at the eastern edge 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 Ti ...

. It has been responsible for many major

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, from ...

s, and is one of the most seismically

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 ...

zones in this part of China.

Tectonic setting

The Xianshuihe fault system lies within the complex zone of

continental collision In geology, continental collision is a phenomenon of plate tectonics that occurs at convergent boundaries. Continental collision is a variation on the fundamental process of subduction, whereby the subduction zone is destroyed, mountains prod ...

between the

Indian 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 ...

. It forms one of a set of sinistral fault zones that help accommodate the eastward spreading of the Tibetan Plateau. The fault zone defines the northern and eastern edges of the Sichuan-Yunnan block, and the southeastern boundary of the

Bayan Har block The Bayan Har block or Bayan Kola block is an elongate wedge-shaped block that forms part of the eastern Tibetan Plateau. It is bounded to the southeast by the Longmenshan Fault, a major thrust fault zone, which forms the active tectonic boundary b ...

Geometry

The Xianshuihe fault system comprises several distinct segments, with an overall length of about 350 km. The main segments are the Ganzi (or Ganzi-Yushu), the Xianshuihe, the Anninghe-Zemuhe, and the Xiaojiang faults.

Seismicity

Movements on this fault system have been responsible for many large historical earthquakes, with more than 20 events of magnitude greater than 6.5 since 1700. Some of these earthquakes have formed linked sequences, with each event being triggered by the previous one due to stress changes.

Creep

Like the

San Andreas Fault The San Andreas Fault is a continental transform fault that extends roughly through California. It forms the tectonics, tectonic boundary between the Pacific Plate and the North American Plate, and its motion is Fault (geology)#Strike-slip fau ...

in California, the Xianshuihe exhibits a behavior called

Aseismic creep In geology, aseismic creep or fault creep is measurable surface displacement along a fault in the absence of notable earthquakes. Aseismic creep may also occur as "after-slip" days to years after an earthquake. Notable examples of aseismic slip in ...

. The Xianshuihe fault creeps at a rate of a few mm/yr between earthquakes.

Notable earthquakes

1786 Kangding-Luding earthquake An earthquake occurred on 1 June 1786 in and around Kangding, in what is now China's Sichuan 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 q ...

* 1850 Xichang earthquake *

1923 Renda earthquake 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 7.0–7.3 earthquake was assigned a maximum modified Mercalli intensity scale rating of X (''Extreme'' ...

1955 Zheduotang earthquake The 1955 Zheduotang earthquake, also known as the Kangding earthquake occurred on April 14 at 09:29:02 Time in China, local time near the city of Kangding in the Garzê Tibetan Autonomous Prefecture, Sichuan. The earthquake had a moment magnitud ...

1973 Luhuo earthquake The 1973 Luhuo earthquake struck near the town of Zhaggo in the Garzê Tibetan Autonomous Prefecture of Sichuan Province, China on February 6 with a magnitude of 7.6 . The earthquake had a maximum intensity of X (''Extreme'') on the Mercalli inte ...

1981 Dawu earthquake The 1981 Dawu earthquake occurred on , in Sichuan, China. Registering a surface wave magnitude of 6.8, the earthquake killed about 150 people and injured roughly 300 more. It caused comprehensive damage within close range of its epicenter. Back ...

2010 Yushu earthquake The 2010 Yushu earthquake struck on April 14 and registered a magnitude of 6.9 Mw (USGS, EMSC) or 7.1 Ms2022 Luding earthquake A 6.7 ( 6.8) earthquake struck Luding County in Sichuan provinces of China, province, China on 5 September 2022 at 12:52:19 Time in China, local time. The epicenter was located from Chengdu, or southeast of Kangding. Ninety-three people died, ...

References