Avachinsky (also known as Avacha or Avacha Volcano or Avachinskaya Sopka) () is an active

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

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 ...

. It is situated 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 ...

. Avachinsky lies within sight of Petropavlovsk-Kamchatsky, the capital 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 ...

. Together with neighbouring Koryaksky volcano, it is considered a Decade Volcano, 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 The volcanic explosivity index (VEI) is a scale used to measure the size of explosive volcanic eruptions. It was devised by Christopher G. Newhall of the United States Geological Survey and Stephen Self in 1982. Volume of products, eruption c ...

4 eruption in 1945.

Geological history

Avachinsky lies on the Pacific Ring of Fire, at a point where the Pacific Plate is sliding underneath the Eurasian Plate at a rate of about /year. A wedge of mantle material lying between the subducting 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 ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

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 volcanic eruption. An eruption that ejects large volumes of magma over a short period of time can cause significant detriment to the str ...

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

landslide Landslides, also known as landslips, rockslips or rockslides, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, mudflows, shallow or deep-seated slope failures and debris flows. Landslides ...

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

. Eruptions have generally been explosive, and pyroclastic flows 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 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 (sometimes colloquially but incorrectly referred to as ''lava'') is found beneath the surface of the Earth, and evidence of magmatism has also ...

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

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 ...

s, and many fumaroles 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 Decade Volcano 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 Koryaksky 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