View source for Avachinsky

{{Short description|Active stratovolcano on the Kamchatka peninsula, Russia}}
{{Infobox mountain
| name = Avachinsky
| photo = Avachinsky Volcano (23682444539).jpg
| photo_caption = Avachinsky Volcano in September 2014
| elevation_m = 2741
| elevation_ref = <ref name=gvp>{{cite gvp|vn=300100|name=Avachinsky|accessdate=2010-03-05}}</ref>
| prominence_m = 1550
| prominence_ref = 
| map = Russia Far Eastern Federal District
| map_caption = The location of Avachinsky in Russia
| map_size = 300
| label_position = left
| listing = [[Ultra prominent peak|Ultra]], Ribu
| location = [[Kamchatka Peninsula|Kamchatka]], [[Russia]]
| range = [[Eastern Range (Kamchatka)|Eastern Range]]
| coordinates = {{coord|53|15|18|N|158|49|48|E|type:mountain_region:RU_scale:100000|format=dms|display=inline,title}}
| range_coordinates = 
| coordinates_ref = <ref name=gvp/>
| topo = 
| type = [[Stratovolcano]]
| age = Pleistocene
| last_eruption = 2008<ref name=gvp/><ref>[http://www.volcanodiscovery.com/avachinsky.html Avachinsky volcano on VolcanoDiscovery]</ref>
| first_ascent = 
| easiest_route = basic rock/snow climb
}}

'''Avachinsky''' (also known as '''Avacha''' or '''Avacha Volcano''' or '''Avachinskaya Sopka''') ({{langx|ru|Авачинская сопка, Авача}}) 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 capital of [[Kamchatka Krai]]. 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]] 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 {{cvt|80.|mm}}/year. A wedge of [[Mantle (geology)|mantle]] material lying between the [[subduction|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]] era. It has a horseshoe-shaped [[caldera]], which formed 30-40,000&nbsp;years ago in a major [[volcanic landslide|landslide]] which covered an area of {{cvt|500.|km2}} 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&nbsp;years ago.<ref>{{Citation |last1=Droznin |first1=D. |last2=Levin |first2=V. |last3=Park |first3=J. |last4=Gordeev |first4=E. |year=2002 |title=Detailed Mapping of Seismic Anisotropy Indicators in Southeastern Kamchatka |work=American Geophysical Union, Fall Meeting 2002 }}.</ref><ref>{{Citation |last1=Levin |first1=V. |last2=Park |first2=J. |last3=Gordeev |first3=E. |last4=Droznin |first4=D. |year=2002 |title=Complex Anisotropic Structure of the Mantle Wedge Beneath Kamchatka Volcanoes |work=American Geophysical Union, Fall Meeting 2002 |volume=2002 |bibcode=2002AGUFM.T21C1099L }}.</ref><ref>{{Citation |last1=Taran |first1=Y. A. |last2=Connor |first2=C. B. |last3=Shapar |first3=V. N. |last4=Ovsyannikov |first4=A. A. |last5=Bilichenko |first5=A. A. |year=1997 |title=Fumarolic activity of Avachinsky and Koryaksky volcanoes, Kamchatka, from 1993 to 1994 |journal=Bulletin of Volcanology |volume=58 |issue=6 |pages=441–448 |doi=10.1007/s004450050152 |bibcode = 1997BVol...58..441T |s2cid=51397641 }}.</ref>

<gallery>
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.
</gallery>

==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.
{{Cquote|On the 15th it continued calm until noon when it clouded up and became very black and dark: the two mountains Peter and Paul were covered with the atmosphere near half way from their summits down, and at two o'clock we had again a small shock of an earthquake, and heard a hollow rumbling noise in the air, and the atmosphere continuing to condense, it became almost as dark as night, and the face of heaven looked very wild: we singled the stops of the sheet-anchor and eased the ship aloft at all the portentous appearances.  Between three and four the mountain Paul exploded with a tremendous shock that convulsed everything around us: The report that attended the explosion was very loud at first, but gradually decreased until it subsided to a sound like that of grumbling distant thunder.<ref>{{Citation |editor-last=Zug |editor-first=James |year=2005 |title=The Last Voyage of Captain Cook: The Collected Writings of John Ledyard |location=Washington, DC |publisher=National Geographic Society |isbn=0-7922-9347-9 |page=115 }}.</ref>}}

==Recent activity==
[[File:Кратер Авачинского вулкана.jpg|thumb|Avachinsky summit crater filled by a basaltic andesite lava flow]]
Avachinsky has erupted at least 16 times in [[recorded history]]. Eruptions have generally been explosive, and [[pyroclastic flow]]s and [[lahar]]s have tended to be directed to the south west by the breached caldera.  The most recent large eruption ([[Volcanic Explosivity Index|VEI]]=4) occurred in 1945, when about {{cvt|0.25|km3}} of [[magma]] was ejected.  The volcano has since had small eruptions in 1991 and 2001.

The volcano continues to experience frequent [[earthquake]]s, and many [[fumarole]]s exist near the summit.  The temperature of gases emitted at these fumaroles has been measured at over {{cvt|400.|°C}}. In light of its proximity to Petropavlovsk-Kamchatsky, Avachinsky was designated a [[Decade Volcano]] in 1996 as part of the [[United Nations]]' International Decade for Natural Disaster Reduction, together with the nearby [[Koryaksky]] volcano.

==See also==
{{commons category|Avachinsky Volcano}}
*[[List of volcanoes in Russia]]

{{-}}

==References==
{{Reflist}}

==External links==
* [http://volcano.oregonstate.edu/vwdocs/volc_images/north_asia/kamchatka/Avachinsky.html  VolcanoWorld information] {{Webarchive|url=https://web.archive.org/web/20191222055749/http://volcano.oregonstate.edu/vwdocs/volc_images/north_asia/kamchatka/Avachinsky.html |date=2019-12-22 }}

{{Decade Volcanoes}}


[[Category:Active volcanoes]]
[[Category:Decade Volcanoes]]
[[Category:Volcanoes of the Kamchatka Peninsula]]
[[Category:Mountains of the Kamchatka Peninsula]]
[[Category:VEI-4 volcanoes]]
[[Category:Calderas of Russia]]
[[Category:Stratovolcanoes of Russia]]
[[Category:Holocene stratovolcanoes]]
[[Category:Holocene Asia]]
[[Category:Pleistocene stratovolcanoes]]