Koryaksky or Koryakskaya Sopka (russian: Коря́кская со́пка) is an active

volcano A volcano is a rupture 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 often found where tectonic plates are ...

on the

Kamchatka Peninsula The Kamchatka Peninsula (russian: полуостров Камчатка, Poluostrov Kamchatka, ) 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 we ...

in the

Russian Far East The Russian Far East (russian: Дальний Восток России, r=Dal'niy Vostok Rossii, p=ˈdalʲnʲɪj vɐˈstok rɐˈsʲiɪ) is a region in Northeast Asia. It is the easternmost part of Russia and the Asian continent; and is admini ...

. It lies within sight of Kamchatka Krai's administrative center,

Petropavlovsk-Kamchatsky Petropavlovsk-Kamchatsky ( rus, Петропавловск-Камчатский, a=Петропавловск-Камчатский.ogg, p=pʲɪtrɐˈpavləfsk kɐmˈtɕatskʲɪj) is a city and the administrative, industrial, scientific, and cultur ...

. Together with neighbouring

Avachinsky Avachinsky (also known as Avacha or Avacha Volcano or Avachinskaya Sopka) (russian: Авачинская сопка, Авача) is an active stratovolcano in Russia. It is situated on the Kamchatka Peninsula in the Russian Far East. Avachinsky ...

, it has been designated 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 prox ...

, 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 region around much of the rim of the Pacific Ocean where many Types of volcanic eruptions, volcanic eruptions and ...

, at a point where the

Pacific Plate The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At , it is the largest tectonic plate. The plate first came into existence 190 million years ago, at the triple junction between the Farallon, Phoenix, and Iza ...

is sliding underneath 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 ...

at about per year. A wedge of mantle material lying between the

subducting Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...

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 moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or und ...

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 ...

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 ash and tephra suspended in gases emitted during an explosive volcanic eruption. The volcanic materials form a vertical column or plume that may rise many kilometers into the air a ...

was simply steam generated by strong

fumarolic A fumarole (or fumerole) is a vent in the surface of the Earth or other 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 volc ...

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 jv, ꦮ꧀ꦭꦲꦂ) is a violent type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris and water. The material flows down from a volcano, typically along a river valley. Lahars are extreme ...

s. The eruption continued until June 1957. On December 29, 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 an intergovernmental organization whose stated purposes are to maintain international peace and international security, security, develop friendly relations among nations, achieve international cooperation, and be ...

' 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, ocean, hydrologic, space, and planetary scientists and enthusiasts that according to their website includes 130,000 people (not members). AGU's act ...

, 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