On November 2 of 1946, west

Kyrgyzstan Kyrgyzstan,, pronounced or the Kyrgyz Republic, is a landlocked country in Central Asia. Kyrgyzstan is bordered by Kazakhstan to the north, Uzbekistan to the west, Tajikistan to the south, and the People's Republic of China to the east. ...

(then the

Kirghiz Soviet Socialist Republic The Kirghiz Soviet Socialist Republic (Kirghiz SSR; ky, Кыргыз Советтик Социалисттик Республикасы, Kyrgyz Sovettik Sotsialisttik Respublikasy, ky, Кыргыз ССР, Kyrgyz SSR, russian: Киргизск ...

in the

Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...

) was struck by a magnitude 7.5-7.6

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 ...

, the largest in the republic since 1911. The earthquake's

hypocenter In seismology, a hypocenter or hypocentre () is the point of origin of an earthquake or a subsurface nuclear explosion. A synonym is the focus of an earthquake. Earthquakes An earthquake's hypocenter is the position where the strain energy s ...

is probably located beneath the

Tien Shan Mountains The Tian Shan,, , otk, 𐰴𐰣 𐱅𐰭𐰼𐰃, , tr, Tanrı Dağı, mn, Тэнгэр уул, , ug, تەڭرىتاغ, , , kk, Тәңіртауы / Алатау, , , ky, Теңир-Тоо / Ала-Тоо, , , uz, Tyan-Shan / Tangritog‘ ...

, near the border with

Uzbekistan Uzbekistan (, ; uz, Ozbekiston, italic=yes / , ; russian: Узбекистан), officially the Republic of Uzbekistan ( uz, Ozbekiston Respublikasi, italic=yes / ; russian: Республика Узбекистан), is a doubly landlocked cou ...

and north of

Namangan Namangan (; ) is a city in eastern Uzbekistan. It is the administrative, economic, and cultural center of Namangan Region. Administratively, it is a district-level city. Namangan is located in the northern edge of the Fergana Valley, less than 30 ...

. The earthquake had a maximum intensity of X (''Extreme'') on the

Mercalli intensity scale The Modified Mercalli intensity scale (MM, MMI, or MCS), developed from Giuseppe Mercalli's Mercalli intensity scale of 1902, is a seismic intensity scale used for measuring the intensity of shaking produced by an earthquake. It measures the eff ...

, and IX on the MSK scale. This shock rocked the entire country and

Tian Shan Range The Tian Shan,, , otk, 𐰴𐰣 𐱅𐰭𐰼𐰃, , tr, Tanrı Dağı, mn, Тэнгэр уул, , ug, تەڭرىتاغ, , , kk, Тәңіртауы / Алатау, , , ky, Теңир-Тоо / Ала-Тоо, , , uz, Tyan-Shan / Tangritog‘ ...

. Severe property damage was reported in its aftermath but the number of deaths and injuries remains unknown. It has been considered one of the most devastating earthquakes in

Central Asia Central Asia, also known as Middle Asia, is a subregion, region of Asia that stretches from the Caspian Sea in the west to western China and Mongolia in the east, and from Afghanistan and Iran in the south to Russia in the north. It includes t ...

. Two days later, a magnitude 6.9 earthquake struck nearby Turkmenistan, killing 400 people.

Tectonic setting

The Talas-Fergana Fault is a massive 800-km-long intracontinental

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 running through the Tien Shan Mountains, the largest in Central Asia. It has produced several significant earthquakes with magnitude 7.0 or greater in the past 6000 years with recurrence intervals on segments of the fault between 145 and 850 years, and an average of 375 years. Earlier studies and research on this event concluded that the earthquake occurred on a secondary branch of this fault known as the Atoinok

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. If ...

Effects

Man-made structures within a 1,500 km² area around the epicenter were completely destroyed. The villages of Shuduger, Kichitovar, Chontovar were severely damaged or totally destroyed. Intensity X to VIII was evaluated to occupy an area perpendicular to the

Chatkal Range Chatkal Range is a range in the Western Tian Shan that borders Ferghana Valley from northwest. The length of the range is 225 km, and it is up to 30 km wide. The highest peak is Avletim (4503 m elevation). Northern slopes are steep and sh ...

, and parallel to the fault. The meizoseismal area however, was parallel to the Talas-Fergana Fault, indicating most of the seismic energy was released parallel to the fault instead.

Landslides Landslides, also known as landslips, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, deep-seated slope failures, mudflows, and debris flows. Landslides occur in a variety of environments, ...

loams Loam (in geology and soil science) is soil composed mostly of sand (particle size > ), silt (particle size > ), and a smaller amount of clay (particle size < ). By weight, its mineral composition is about 40–40–20% concentration of sand–sil ...

and rockfalls dammed rivers. A rockfall dammed the

Naryn River The Naryn ( ky, Нарын, uz, Norin) rises in the Tian Shan mountains in Kyrgyzstan, Central Asia, flowing west through the Fergana Valley into Uzbekistan. Here it merges with the Kara Darya (near Namangan) to form the Syr Darya. It is long ( ...

, forming a

quake lake Quake Lake (officially Earthquake Lake) is a lake in the western United States, on the Madison River in southwestern Montana. It was created after an earthquake struck on August 17, 1959, with 28 fatalities. Northwest of West Yellowstone, Qua ...

. This threatened the small community of

Toktogul Toktogul ( ky, Toктогул, known until 31 July 1957 as ''Muztör'' ()), is a city (since 2012) in Jalal-Abad Region of Kyrgyzstan. Its population was 20,577 in 2021. It is the administrative seat of Toktogul District. It is named after its mos ...

with a possibility the rockfall dam breaching, causing a surge.

Surface ruptures A surface, as the term is most generally used, is the outermost or uppermost layer of a physical object or space. It is the portion or region of the object that can first be perceived by an observer using the senses of sight and touch, and is t ...

up to 300 meters long and 50 meters wide fissured the landscape. The earthquake's strength was also felt in

Osh Osh (Kyrgyz: Ош, romanised Osh; uz, O‘sh/Ўш) is the second-largest city in Kyrgyzstan, located in the Fergana Valley in the south of the country and often referred to as the "capital of the south". It is the oldest city in the country (e ...

and

Tashkent, Uzbekistan Tashkent (, uz, Toshkent, Тошкент/, ) (from russian: Ташкент), or Toshkent (; ), also historically known as Chach is the Capital city, capital and List of cities in Uzbekistan, largest city of Uzbekistan. It is the most populous ...

where the shaking intensity was VI (''Strong'') to IV (''Light''), causing substantial damage to buildings.

Aftershocks

Numerous

aftershocks In seismology, an aftershock is a smaller earthquake that follows a larger earthquake, in the same area of the main shock, caused as the displaced crust adjusts to the effects of the main shock. Large earthquakes can have hundreds to thousand ...

continued throughout the region. The largest included a magnitude 5.5 and 5.4 in 1955 and 1959. Another magnitude 5.6 struck near Toktogul Reservoir on October 28 1971.

References

{{Earthquakes in Kyrgyzstan 1946 earthquakes Earthquakes in Kyrgyzstan Earthquakes in Kazakhstan Earthquakes in Uzbekistan Earthquakes in the Soviet Union Earthquakes in Russia 1946 in the Soviet Union 1946 in Russia

Tectonic setting

Effects

Aftershocks

See also

References