Avachinsky (also known as Avacha or Avacha Volcano or Avachinskaya Sopka) (russian: Авачинская сопка, Авача) is an active

stratovolcano A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and per ...

Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...

. It is situated 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 ...

. Avachinsky lies within sight of

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

, the capital of Kamchatka Krai. Together with neighboring

Koryaksky Koryaksky or Koryakskaya Sopka (russian: Коря́кская со́пка) is an active volcano on the Kamchatka Peninsula in the Russian Far East. It lies within sight of Kamchatka Krai's administrative center, Petropavlovsk-Kamchatsky. Togeth ...

volcano, 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. Avachinsky's last eruption occurred in 2008. This eruption was tiny compared to the volcano's major Volcanic Explosivity Index 4 eruption in 1945.

Geological history

Avachinsky 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 a rate of about /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 is one of the most active volcanoes on the Kamchatka Peninsula, and began erupting in the middle to late

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

era. It has a horseshoe-shaped

caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is ...

, which formed 30-40,000 years ago in a major

landslide 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 grade (slope), slope failures, mudflows, and debris flows. Landslides occur in a variety of ...

which covered an area of south of the volcano, underlying the city of Petropavlovsk-Kamchatsky. Reconstruction of a new cone inside the caldera occurred in two major eruption phases, 18,000 and 7,000 years ago.. Avachinsky Volcano.jpg, Seen from base camp. Image:Avachinsky Summit.jpg, Avachinsky Summit. Image:Koryaksky and Avachinsky volcanoes from the ISS.jpg, Avachinsky (centre, nearest coast) from space. Image:Avachinsky Volcano, Kamchatka Peninsula.JPG, Astronaut photograph highlighting the summit crater and snow-covered slopes of the Avachinsky.

Recorded history

In his Journal of Captain Cook's Last Voyage,

John Ledyard John Ledyard (November 1751 – 10 January 1789) was an American explorer and adventurer. Early life Ledyard was born in Groton, Connecticut, in November 1751. He was the first child of Abigail Youngs Ledyard and Capt. John Ledyard Jr, son o ...

records the eruption of Avachinsky on June 15, 1779. He refers to

and Avachinsky as Peter and Paul.

Recent activity

Avachinsky has erupted at least 16 times in

recorded history Recorded history or written history describes the historical events that have been recorded in a written form or other documented communication which are subsequently evaluated by historians using the historical method. For broader world hist ...

. Eruptions have generally been explosive, and

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 have tended to be directed to the south west by the breached caldera. The most recent large eruption ( VEI=4) occurred in 1945, when about of

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...

was ejected. The volcano has since had small eruptions in 1991 and 2001. The volcano continues to experience frequent

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 many

fumarole 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 volcani ...

s exist near the summit. The temperature of gases emitted at these fumaroles has been measured at over . In light of its proximity to Petropavlovsk-Kamchatsky, Avachinsky 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

External links

VolcanoWorld information
{{Decade Volcanoes Active volcanoes Decade Volcanoes Volcanoes of the Kamchatka Peninsula Mountains of the Kamchatka Peninsula VEI-4 volcanoes Calderas of Russia Stratovolcanoes of Russia Holocene stratovolcanoes Holocene Asia Pleistocene stratovolcanoes

Geological history

Recorded history

Recent activity

See also

References

External links