Atka

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  • Country
  • Subregion Name
  • Primary Volcano Type
  • Last Known Eruption
  • 52.332°N
  • 174.137°W

  • 1451 m
    4759 ft

  • 311160
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

1 November-7 November 2006

The number of daily earthquakes beneath Atka increased in July and remained elevated into November. Episodes of volcanic tremor that first occurred in September increased in number, strength, and duration in the past several weeks. On 28 October, residents of Atka observed steam emissions to many hundreds of meters above the summit. On 6 November, the AVO raised the Aviation Level of Concern Color Code to Yellow and the Volcanic Alert Level to Advisory due to the high seismicity and steam emissions.

Source: US Geological Survey Alaska Volcano Observatory (AVO)



 Available Weekly Reports


2006: February | March | November
2005: February | March


1 November-7 November 2006

The number of daily earthquakes beneath Atka increased in July and remained elevated into November. Episodes of volcanic tremor that first occurred in September increased in number, strength, and duration in the past several weeks. On 28 October, residents of Atka observed steam emissions to many hundreds of meters above the summit. On 6 November, the AVO raised the Aviation Level of Concern Color Code to Yellow and the Volcanic Alert Level to Advisory due to the high seismicity and steam emissions.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


8 March-14 March 2006

AVO decreased the Concern Color Code at Korovin volcano in the Atka volcanic center from Yellow to Green (the lowest level) on 8 March. After raising the Concern Color Code on 22 February in response to increased seismicity, the rate of micro-earthquakes stabilized and then declined. During 1-8 March, seismicity was near background levels and no unusual activity was seen on satellite imagery or by observers.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


1 March-7 March 2006

Seismicity at Korovin volcano in the Atka volcanic center remained slightly above background levels during 24 February to 3 March. Clouds obscured satellite views of the volcano, and AVO received no reports of activity. There were no indications that an eruption was imminent. The volcano remained at Concern Color Code Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


22 February-28 February 2006

AVO reported that the Concern Color Code at Korovin volcano in the Atka volcanic center was raised from Green to Yellow on 22 February due to an increase in seismicity at the volcano. Distinct seismic signals indicating unrest were recorded on 4 days between 17 and 22 January, with a sustained 11-minute-long seismic signal on 22 February. After 22 February, seismicity decreased and distinct seismic signals like those recorded earlier were not detected. Clouds obscured satellite views of the volcano after 22 February. A pilot report on the 22nd indicated that the summit area was obscured by clouds, and there were no signs of ashfall on the flanks and no steam plume above the volcano. No obvious signs of activity were seen on 23 February by observers in the village of Atka. AVO received no reports of volcanic activity and there were no indications that an eruption was imminent.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


2 March-8 March 2005

AVO did not receive reports of activity at Korovin volcano in the Atka volcanic center after the original report of ash-and-steam emissions on 24 February. During 25 February to 4 March, cloud cover prohibited satellite views of the volcano and no unusual seismicity was registered. Korovin is not monitored by a standard AVO seismic network. Therefore, AVO did not assign a Concern Color Code to the volcano during the report period.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


23 February-1 March 2005

On 24 February AVO raised the Concern Color Code at Korovin volcano of the Atka volcanic center from Green to Yellow after receiving a report that ash and steam were emitted from Korovin on 23 February around 1900. According to residents of Atka village near the volcano, the initial ash burst rose to a height of ~ 2.4 km a.s.l. and drifted E. It was followed by several smaller ash-and-steam bursts. No ashfall was reported in Atka village, nor were there reports of accompanying volcanic odors, earthquakes, or larger volcanic explosions. Satellite images of the volcano did not clearly show the presence of ash or any thermal anomalies. On the morning of 24 February the volcano was steaming. AVO warned that low-level steam-and-ash emissions may continue and could pose a hazard to people and low- to medium-flying aircraft in the vicinity of the volcano. They further warned that if the eruption continues and begins to intensify, light ash fall could occur on parts of Atka Island, including the village of Atka.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


Summary of eruption dates and Volcanic Explosivity Indices (VEI).

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
[ 1995 May 1 ] [ Unknown ] Uncertain 1  
1987 Mar 18 1987 Mar 19 (?) Confirmed 2 Historical Observations Kliuchef SW and WSW flanks
1812 Unknown Confirmed 3 Historical Observations Sarichef or more probably Kliuchef

The following references are the sources used for data regarding this volcano. References are linked directly to our volcano data file. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title. Additional discussion of data sources can be found under Volcano Data Criteria.

Coats R R, 1950. Volcanic activity in the Aleutian Arc. U S Geol Surv Bull, 974-B: 35-47.

IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth's Interior..

Miller T P, McGimsey R G, Richter D H, Riehle J R, Nye C J, Yount M E, Dumoulin J A, 1998. Catalogue of the historically active volcanoes of Alaska. U S Geol Surv Open-File Rpt, 98-582: 1-104.

Motyka R J, Liss S A, Nye C J, Moorman M A, 1993. Geothermal resources of the Aleutian arc. Alaska Div Geol Geophys Surv, Prof Rpt, no 114, 17 p and 4 map sheets.

Myers J D, 1994. The Geology, Geochemistry and Petrology of the recent Magmatic Phase of the Central and Western Aleutian Arc. Unpublished manuscript, unpaginated.

Myers J D, March B D, Sinha A K, 1985. Strontium isotopic and selected trace element variations between two Aleutian volcanic centers (Adak and Atka): implications for the development of arc volcanic plumbing systems. Contr Mineral Petr, 91: 221-234.

Myers J D, Marsh B D, Frost C D, Linton J A, 2002. Petrologic constraints on the spatial distribution of crustal magma chambers, Atka volcanic center, central Aleutian arc. Contr Mineral Petr, 143: 567-586.

Smith R L, Shaw H R, Luedke R G, Russell S L, 1978. Comprehensive tables giving physical data and thermal energy estimates for young igneous systems of the United States. U S Geol Surv Open-File Rpt, 78-925: 1-25.

Wood C A, Kienle J (eds), 1990. Volcanoes of North America. Cambridge, England: Cambridge Univ Press, 354 p.

The largest volcanic center in the central Aleutians, Atka consists of a central shield and Pleistocene caldera with several post-caldera volcanoes. A major dacitic explosive eruption accompanied formation of the caldera about 500,000 to 300,000 years ago. The most prominent of the post-caldera stratovolcanoes are Kliuchef and Sarichef, both of which may have been active in historical time. Sarichef has a symmetrical profile, but the less eroded Kliuchef is the source of most if not all historical eruptions. Kliuchef may have been active on occasion simultaneously with Korovin volcano to the north. Hot springs and fumaroles are located on the flanks of Mount Kliuchef and in a glacial valley SW of Kliuchef.