The 1911 Kebin earthquake, or Chon-Kemin earthquake, struck

Russian Turkestan Russian Turkestan () was a colony of the Russian Empire, located in the western portion of the Central Asian region of Turkestan. Administered as a Krai or Governor-Generalship, it comprised the oasis region to the south of the Kazakh Steppe, b ...

on 3 January. Registering at a moment magnitude of 8.0, it killed 452 people, destroyed more than 770 buildings (which was almost all of the city) in

Almaty Almaty, formerly Alma-Ata, is the List of most populous cities in Kazakhstan, largest city in Kazakhstan, with a population exceeding two million residents within its metropolitan area. Located in the foothills of the Trans-Ili Alatau mountains ...

Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a landlocked country primarily in Central Asia, with a European Kazakhstan, small portion in Eastern Europe. It borders Russia to the Kazakhstan–Russia border, north and west, China to th ...

, and resulted in of surface faulting in the valleys of Chon-Kemin, Chilik and Chon-Aksu.

Tectonic setting

The

Tien Shan The Tian Shan, also known as the Tengri Tagh or Tengir-Too, meaning the "Mountains of God/Heaven", is a large system of mountain ranges in Central Asia. The highest peak is Jengish Chokusu at high and located in Kyrgyzstan. Its lowest point is ...

mountains form part of the broad 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 for ...

between the

Indian plate The Indian plate (or India plate) is or was 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 an ...

and the Eurasian plate. In the region around

Issyk Kul Issyk-Kul () or Ysyk-Köl (, ; ) is an endorheic saline lake in the western Tianshan Mountains in eastern Kyrgyzstan, just south of a dividing range separating Kyrgyzstan from Kazakhstan. It is the eighth-deepest lake in the world, the eleve ...

, the tectonic regime is a combination of

thrusting Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that syst ...

and sinistral

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 ...

. The lake is formed in a ramp basin bounded to both north and south by opposite verging thrust faults, while the major Chon-Kemin–Chilik strike-slip fault runs along the linear valleys to the north.

Characteristics

In the Chong-Kemin and Chilik valleys, and on the shoreline of Issyk Kul, a complex zone of

surface rupture In seismology, surface rupture (or ground rupture, or ground displacement) is the visible offset of the ground surface when an earthquake rupture along a Fault (geology), fault affects the Earth's surface. Surface rupture is opposed by buried rup ...

was identified by fieldwork immediately following the earthquake. Two main zones of rupture were noted, one complex zone along the Chon-Kemin and Chilik valleys, the other along the Chon-Aksu valley.

Chon-Kemin Chilik rupture zone

This complex zone of ruptures has four main segments: the 20 km long Dzhil'-Aryk, the 62 km long Lower Chon-Kemin, south side, the 40 km long Lower Chon-Kemin, north side and the 66 km long Upper Chon-Kemin-Chilik zone. The Dzhil'-Aryk segment shows evidence of reverse faulting on a south-dipping fault plane, with no clear evidence of lateral movement. The sense of displacement along the rest of the near-vertical Chon-Kemin and Chilik rupture zone was dominantly of sinistral (left lateral) strike-slip with minor amounts of reverse faulting, with between one and three metres of vertical displacement. Left-lateral displacements of up to 40 m recognised from the offset of river channels, represent cumulative displacements and no separate estimates have been obtained for the 1911 event.

Chon-Aksu Aksu rupture zone

This zone has two parts: the 40 km long Chon-Aksu segment and the 34 km long Aksu segment. Along the Chon-Aksu valley the movement was dominantly reverse in type along a 60° north-dipping reverse fault, with up to 10.5 m vertical displacement and at most 1 m horizontal displacement, from the lack of observed offset of river

thalweg In geography, hydrography, and fluvial geomorphology, a thalweg or talweg () is the line or curve of lowest elevation within a valley or watercourse. Normally only the horizontal position of the curve is considered (as viewed on a map); the c ...

s. The outcrop pattern of the Aksu segment rupture indicates a low-angle

thrust Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that ...

, possibly steepening with depth, with a maximum vertical offset or 3–5 m, decreasing steadily to the east. In total about 200 km of fault surfaces ruptured, although there was no visible faulting joining the two main rupture zones.

Landslides

Many landslides and rock avalanches were triggered by the earthquake and are associated with the mapped zones of surface rupture. The two largest landslides were the Kaindy rock avalanche and the Ananevo rockslide. The Kaindy landslide, with a volume of 15 x 10⁶ m³, was formed of a mass of

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

that buried a group of yurts and killed 38 people. The Ananevo rockslide also had a volume of about 15 x 10⁶ m³, and was formed of weathered

granitic A granitoid is a broad term referring to a diverse group of coarse-grained igneous rocks that are widely distributed across the globe, covering a significant portion of the Earth's exposed surface and constituting a large part of the continental ...

material, with a 250 m high backscarp that is still visible.

Impact

Most of the region's inhabitants lived in

yurt A yurt (from the Turkic languages) or ger (Mongolian language, Mongolian) is a portable, round tent covered and Thermal insulation, insulated with Hide (skin), skins or felt and traditionally used as a dwelling by several distinct Nomad, nomad ...

s, which are relatively resistant to earthquakes and unlikely to cause deaths even if they do collapse. The greatest damage and most of the casualties, including in yurts, resulted from landslides triggered by the earthquake, with 452 people killed and another 740 people injured. Nearly 1,100 houses and 4,545 yurts were destroyed by the earthquake and the resulting landslides.

References

External links

* {{authority control Earthquakes in Russia Earthquakes in Kazakhstan Earthquakes in Kyrgyzstan

Earthquake An earthquakealso called a quake, tremor, or tembloris the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they ...

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

January 1911 1910s disasters in the Russian Empire 1911 disasters in Asia