Koryaksky or Koryakskaya Sopka () is an active

volcano A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most oft ...

on the

Kamchatka Peninsula The Kamchatka Peninsula (, ) is a peninsula in the Russian Far East, with an area of about . The Pacific Ocean and the Sea of Okhotsk make up the peninsula's eastern and western coastlines, respectively. Immediately offshore along the Pacific ...

in the

Russian Far East The Russian Far East ( rus, Дальний Восток России, p=ˈdalʲnʲɪj vɐˈstok rɐˈsʲiɪ) is a region in North Asia. It is the easternmost part of Russia and the Asia, Asian continent, and is coextensive with the Far Easte ...

. It lies within sight of

Kamchatka Krai Kamchatka Krai (, ) is a federal subjects of Russia, federal subject of Russia (a krai), situated in the Russian Far East. It is administratively part of the Far Eastern Federal District. Its administrative center and largest types of inhabited l ...

's administrative center,

Petropavlovsk-Kamchatsky Petropavlovsk-Kamchatsky (, ) is a city and the administrative center of Kamchatka Krai, Russia. It is located in the Far East of the country and lies along the coast of Avacha Bay by the Pacific Ocean, nearby Khalaktyrskoye Lake. As of the 202 ...

. Together with neighbouring

Avachinsky Avachinsky (also known as Avacha or Avacha Volcano or Avachinskaya Sopka) () is an active stratovolcano in Russia. It is situated on the Kamchatka Peninsula in the Russian Far East. Avachinsky lies within sight of Petropavlovsk-Kamchatsky, the c ...

, it is considered a

Decade Volcano The Decade Volcanoes are 16 volcanoes identified by the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) as being worthy of particular study in light of their history of large, destructive eruptions and pr ...

, worthy of particular study in light of its history of explosive eruptions and proximity to populated areas.

Geological history

Koryaksky lies on the

Pacific Ring of Fire The Ring of Fire (also known as the Pacific Ring of Fire, the Rim of Fire, the Girdle of Fire or the Circum-Pacific belt) is a tectonic belt of volcanoes and earthquakes. It is about long and up to about wide, and surrounds most of the Pa ...

, at a point where the Pacific Plate is sliding underneath the Eurasian Plate at about per year. A wedge of mantle material lying between the

subducting Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second pla ...

Pacific Plate and the overlying Eurasian Plate is the source of dynamic volcanism over the whole Kamchatka Peninsula. The volcano has probably been active for tens of thousands of years. Geological records indicate that there have been three major eruptions in the last 10,000 years, at 5500 BC, 1950 BC and 1550 BC. These three eruptions seem to have been mainly effusive, generating extensive

lava flow Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...

Recent activity

Koryaksky erupted for the first time in recorded history in 1890. The eruption was characterised by lava emissions from

fissure A fissure is a long, narrow crack opening along the surface of Earth. The term is derived from the Latin word , which means 'cleft' or 'crack'. Fissures emerge in Earth's crust, on ice sheets and glaciers, and on volcanoes. Ground fissure A ...

s that opened up on the volcano's southwestern flank, and by

phreatic explosion A phreatic eruption, also called a phreatic explosion, ultravulcanian eruption or steam-blast eruption, occurs when magma heats ground water or surface water. The extreme temperature of the magma (anywhere from ) causes near-instantaneous evapo ...

s. It was thought to have erupted again five years later, but it was later shown that no eruption had occurred; what was thought to be an

eruption column An eruption column or eruption plume is a cloud of super-heated Volcanic ash, ash and tephra suspended in volcanic gas, gases emitted during an explosive eruption, explosive volcanic eruption. The volcanic materials form a vertical column or Plu ...

was simply steam generated by strong

fumarolic A fumarole (or fumerole) is a vent in the surface of the Earth or another rocky planet from which hot volcanic gases and vapors are emitted, without any accompanying liquids or solids. Fumaroles are characteristic of the late stages of volcani ...

activity. Another brief, moderately explosive eruption occurred in 1926, after which the volcano lay dormant until 1956. The 1956 eruption was more explosive than the previous known eruptions, with VEI=3, and generated

pyroclastic flow A pyroclastic flow (also known as a pyroclastic density current or a pyroclastic cloud) is a fast-moving current of hot gas and volcanic matter (collectively known as tephra) that flows along the ground away from a volcano at average speeds of b ...

s and

lahar A lahar (, from ) is a violent type of mudflow or debris flow composed of a slurry of Pyroclastic rock, pyroclastic material, rocky debris and water. The material flows down from a volcano, typically along a valley, river valley. Lahars are o ...

s. The eruption continued until June 1957. On 29 December 2008, Koryaksky erupted with a plume of ash, the first major eruption in 3,500 years. In light of its proximity to

, Koryaksky was designated a

in 1996 as part of the

United Nations The United Nations (UN) is the Earth, global intergovernmental organization established by the signing of the Charter of the United Nations, UN Charter on 26 June 1945 with the stated purpose of maintaining international peace and internationa ...

' International Decade for Natural Disaster Reduction, together with the nearby

volcano.

References

Notes

Sources

*Droznin D., Levin V., Park J., Gordeev E. (2002), ''Detailed Mapping of Seismic Anisotropy Indicators in Southeastern Kamchatka'',

American Geophysical Union The American Geophysical Union (AGU) is a 501(c)(3) nonprofit organization of Earth, Atmospheric science, atmospheric, Oceanography, ocean, Hydrology, hydrologic, Astronomy, space, and Planetary science, planetary scientists and enthusiasts that ...

, Fall Meeting 2002. *Levin V., Park J., Gordeev E., Droznin D. (2002), ''Complex Anisotropic Structure of the Mantle Wedge Beneath Kamchatka Volcanoes'', American Geophysical Union, Fall Meeting 2002. *Taran Y.A., Connor C.B., Shapar V.N., Ovsyannikov A.A., Bilichenko A.A. (1997), ''Fumarolic activity of Avachinsky and Koryaksky volcanoes, Kamchatka, from 1993 to 1994'', Bulletin of Volcanology, v. 58, p. 441-448.

External links