Shishaldin

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  • Country
  • Subregion Name
  • Primary Volcano Type
  • Last Known Eruption
  • 54.756°N
  • 163.97°W

  • 2857 m
    9371 ft

  • 311360
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

9 April-15 April 2014

AVO reported that elevated surface temperatures over Shishaldin's summit area were detected in satellite images on most days during 9-15 April; cloud cover occasionally prevented observations. Ground-coupled air waves from small explosions detected by the seismic network decreased during 9-10 April. Minor ash deposits were observed several hundred meters down flanks. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)



 Available Weekly Reports


2014: January | February | March | April
2009: January | February | July | October
2008: February | December
2004: April | May | June | July | September | October
2002: May


9 April-15 April 2014

AVO reported that elevated surface temperatures over Shishaldin's summit area were detected in satellite images on most days during 9-15 April; cloud cover occasionally prevented observations. Ground-coupled air waves from small explosions detected by the seismic network decreased during 9-10 April. Minor ash deposits were observed several hundred meters down flanks. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


2 April-8 April 2014

AVO reported that elevated surface temperatures over Shishaldin's summit area were detected in satellite images during 2-8 April. No activity was detected in the seismic data. The webcam showed a steam plume rising from the crater on 6 April. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


26 March-1 April 2014

AVO reported that ground-coupled air waves from small explosions at Shishaldin's summit area were detected in seismic data during 25-27 March, although the energy and rate of occurrence both declined over that time. Elevated surface temperatures were identified in satellite images on 27 March. Based on the elevated surface temperatures and explosions persistent since 18 March AVO raised the Aviation Color Code to Orange and the Volcano Alert Level to Watch on 28 March. Analysis of the data showed that the temperatures were consistent with an eruption of lava within the summit crater. Web-camera images, satellite data, and pilot observations during the previous week indicated only minor steam emissions from the summit crater; there had been no evidence of ash emissions. Explosions were detected during 29-30 March; elevated surface temperatures were identified during 30-31 March.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


19 March-25 March 2014

AVO reported that ground-coupled air waves from small explosions at Shishaldin's summit area were detected in seismic data during 19-25 March. Elevated surface temperatures were identified on most days during this period. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


12 February-18 February 2014

AVO reported that no activity from Shishaldin was observed in party-to-mostly-cloudy satellite images during 12-18 February. The nearest working seismic station detected low seismicity. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


5 February-11 February 2014

AVO reported that elevated surface temperatures in Shishaldin's summit crater were detected in satellite images during 5-6 February. No unusual seismicity was detected by the nearest working station off the flanks of the volcano. A possible ash-poor gas cloud was detected in satellite images beginning at 0645 on 7 February that may have been from a small explosion, too small to be detected by the seismometer but coinciding with a local tiltmeter signal. Satellite image analysis suggested that the short-lived cloud may have risen to an altitude of 7.6 km (25,000 ft) a.s.l. Elevated surface temperatures were not detected after the event, so very little if any hot material was ejected. During 9-11 February elevated surface temperatures were detected in satellite images and a tiltmeter 5.4 km SW of the volcano recorded a small signal. Clear or partly clear web cam images showed no activity. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


29 January-4 February 2014

On 30 January, AVO raised the Aviation Color Code for Shishaldin to Yellow and the Volcano Alert Level to Advisory based on increased surface temperatures detected at the summit crater by satellite images over the previous few days, as well as increased steam emissions observed on 29 January in satellite and web-camera images. No steam emissions were observed during 30-31 January. Elevated surface temperatures were again detected on 1 February.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


14 October-20 October 2009

On 19 October, AVO reported that recent clear satellite views of Shishaldin showed no activity; the last thermal anomaly was detected on 16 August. Seismicity was variable, but within background levels. The Aviation Color Code was lowered to Green and the Volcano Alert Level was lowered to Normal.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


8 July-14 July 2009

On 10 July, AVO reported that a distinct thermal anomaly in Shishaldin's summit crater observed intermittently since January 2009 became more intense during the previous month. AVO raised the Aviation Color Code to Yellow and the Volcano Alert Level to Advisory. AVO also noted that seismicity had not increased, deformation was unchanged, and satellite observations showed no significant sulfur dioxide gas emissions. Some reports of steaming from the summit crater were received.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


11 February-17 February 2009

AVO reported that seismic activity from Shishaldin had returned to background levels in December 2008 and remained low. On 3 February, a weak thermal anomaly was detected on satellite imagery. The Aviation Color Code was lowered to Green and the Volcano Alert Level was lowered to Normal on 11 February.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


7 January-13 January 2009

AVO reported that thermal anomalies over Shishaldin's summit were detected in satellite imagery during 7-10 January. Clouds prevented observations on 11, 12, and 13 January. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


31 December-6 January 2009

AVO reported that significant thermal anomalies over Shishaldin's summit were detected in satellite imagery during 5-6 January. Seismic activity had also increased slightly. AVO raised the Aviation Color Code to Yellow and the Volcano Alert Level to Advisory.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


6 February-12 February 2008

Based on pilot reports, the Anchorage VAAC reported that a small ash plume from Shishaldin rose to an altitude of 3 km (10,000 ft) a.s.l. on 12 February. Ash was not observed on satellite imagery. [Note: AVO received no other reports of an ash plume and did not detect ash on satellite imagery.]

Source: Anchorage Volcanic Ash Advisory Center (VAAC)


20 October-26 October 2004

On 26 October, AVO lowered the Concern Color Code at Shishaldin from Yellow to Green. Volcanic tremor at the volcano had remained at a relatively constant and low level for more than a month. No new satellite observations indicative of significant activity in the summit crater had been received by AVO, and there had been no recent reports of ash emissions or ash on the snow near the summit. The low-level seismic tremor that continued to be recorded at the volcano was considered to be representative of the background rate of activity at Shishaldin.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


15 September-21 September 2004

Low-level seismic tremor continued to be recorded at Shishaldin during 10-17 September. This level of activity is similar to that observed over the past several months. Shishaldin remained at Concern Color Code Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


28 July-3 August 2004

Low-level seismic tremor continued at Shishaldin during 22-30 July as it had for several months. On 24 July an AVO field crew observed vigorous steaming at the summit and what may have been ash deposits on the volcano's upper slopes. Shishaldin remained at Concern Color Code Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


7 July-13 July 2004

Low-level seismic activity characterized by weak but continuous tremor continued at Shishaldin during 7-13 July. No volcanic activity was observed at the volcano during clear weather, but AVO reported that satellite data indicated the crater to be warmer than the surrounding ground surface. Shishaldin remained at Concern Color Code Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


23 June-29 June 2004

Seismic unrest continued at Shishaldin during 18-25 June, with weak tremor and occasional discrete low-frequency earthquakes occurring. A pilot reported seeing steam rise to low levels above Shishaldin's cone. Around that time, a possible weak thermal anomaly was visible on satellite imagery. Shishaldin remained at Concern Color Code Yellow.

Sources: US Geological Survey Alaska Volcano Observatory (AVO), Anchorage Volcanic Ash Advisory Center (VAAC)


26 May-1 June 2004

Seismic unrest continued at Shishaldin during 21-28 May. It was characterized by weak seismic tremor and occasional discrete low-frequency earthquakes. Meteorological clouds obscured views of the volcano. Shishaldin remained at Concern Color Code Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


19 May-25 May 2004

During 14-21 May seismic unrest continued at Shishaldin, characterized by weak seismic tremor and small explosions. On 16 May, a pilot reported an ash plume that rose ~300 m above the volcano's summit. Satellite imagery from 17 May showed a vigorous plume emanating from the summit that may have contained small amounts of ash. Shishaldin remained at Concern Color Code Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


12 May-18 May 2004

During 7-14 May seismic unrest continued at Shishaldin, characterized by sequences of volcanic earthquakes, small explosions, and seismic tremor. A weak thermal anomaly observed at Shishaldin's summit on 11 May was similar to those detected occasionally since January 2004. Shishaldin remained at Concern Color Code Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


5 May-11 May 2004

Seismic unrest continued at Shishaldin during 30 April to 7 May. It was characterized by sequences of volcanic earthquakes and seismic tremor. The number of airwaves recorded by the seismic network diminished in comparison to the previous week, but weaker signals were recorded. Thermal anomalies at the summit were observed on satellite imagery under optimal viewing conditions. Retrospective analysis confirmed that these data, as well as similar signals observed in January 2004, were the first thermal anomalies observed at Shishaldin since August 2000. AVO saw no signs that an eruption was imminent. Shishaldin remained at Concern Color Code Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


28 April-4 May 2004

AVO raised the Concern Color Code at Shishaldin from Green to Yellow on 3 May due to unusual seismic activity at Shishaldin during the previous week. Seismicity changed at the volcano from discrete earthquakes to more continuous ones. Tremor was observed for the first time since the most recent eruption ended in May 1999. Airwaves (acoustical waves traveling in air) accompanying earthquakes were recorded by the seismic network, suggesting that the source of seismicity had become more shallow. AVO reported that there were no indications that an eruption was imminent or even likely. Satellite data showed no significant increase in ground temperature at the volcano, nor had there been reports of increased steaming. However, AVO warned that activity at Shishaldin could increase rapidly and increased the frequency of their seismic-data analysis.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


22 May-28 May 2002

During 17-24 March, the number of locatable low-frequency seismic events at Shishaldin greatly decreased in comparison to the previous week, returning to background levels. Shishaldin remained at Concern Color Code Green ("volcano is in quiet, "dormant" state").

Source: US Geological Survey Alaska Volcano Observatory (AVO)


15 May-21 May 2002

During 10-17 May, the Alaska Volcano Observatory detected an increase in background seismicity at Shishaldin. There was an increase in the number of locatable shallow low-frequency earthquakes and several 2 to- 3-minute-long tremor-like signals that were inferred to be from a deep source. No thermal anomalies were visible on satellite imagery and there were no eyewitness reports of anomalous volcanic activity. Shishaldin remained at Concern Color Code Green ("volcano is in quiet, "dormant" state").

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
[ 2008 Feb 12 ] [ 2008 Feb 12 ] Uncertain 1  
2004 Feb 17 2004 Jul (in or after) Confirmed 2 Historical Observations
[ 2000 Aug 11 ] [ Unknown ] Uncertain    
[ 1999 Sep 25 ± 5 days ] [ 2000 Feb 4 (?) ] Uncertain    
1999 Mar 13 1999 May 27 Confirmed 3 Historical Observations
1998 Nov 4 1998 Nov 4 Confirmed 1 Historical Observations
1997 Jun 2 1997 Jun 2 Confirmed 1 Historical Observations
1995 Dec 23 1996 May 16 (in or before) Confirmed 3 Historical Observations
1993 Sep 4 1993 Oct 29 Confirmed 2 Historical Observations
1986 Mar 19 1987 Feb 15 (?) Confirmed 2 Historical Observations
[ 1981 Sep 25 ] [ Unknown ] Uncertain    
1979 Feb Unknown Confirmed 2 Historical Observations
1978 Feb 8 1978 Feb 9 (?) Confirmed 2 Historical Observations
1976 Jan 1976 Sep 28 Confirmed 2 Historical Observations
1975 Sep 13 1975 Oct 26 ± 5 days Confirmed 2 Historical Observations
1967 Jan 28 Unknown Confirmed 2 Historical Observations
1963 Dec 28 Unknown Confirmed 2 Historical Observations
1955 Jul Unknown Confirmed 2 Historical Observations
1953 Oct 4 ± 3 days Unknown Confirmed 2 Historical Observations
1951 Apr 1951 Oct 5 ± 4 days Confirmed 2 Historical Observations
1948 Unknown Confirmed 2 Historical Observations
1946 Aug 1947 Jan Confirmed 2 Historical Observations
1932 Feb 1 1932 May 21 Confirmed 2 Historical Observations
1929 May 28 1929 Jun 23 (in or after) Confirmed 2 Historical Observations Summit and north flank
1928 Aug Unknown Confirmed 2 Historical Observations
1927 Unknown Confirmed   Historical Observations
1925 Unknown Confirmed   Historical Observations
1922 Oct 15 ± 45 days Unknown Confirmed 2 Historical Observations
[ 1912 ] [ Unknown ] Uncertain    
1901 Unknown Confirmed   Historical Observations
[ 1899 ] [ Unknown ] Uncertain    
1898 Unknown Confirmed 2 Historical Observations
[ 1897 ] [ Unknown ] Uncertain    
1883 Unknown Confirmed 2 Historical Observations
[ 1880 ] [ 1881 ] Uncertain    
[ 1865 ] [ Unknown ] Uncertain    
1842 Unknown Confirmed 2 Historical Observations
1838 Unknown Confirmed 2 Historical Observations
1830 Nov 1830 Dec Confirmed 3 Historical Observations
1827 1829 Confirmed 2 Historical Observations
1826 Unknown Confirmed 0 Historical Observations
1825 Unknown Confirmed 2 Historical Observations NE flank (1300 m)
1824 Unknown Confirmed 3 Historical Observations
[ 1790 ] [ Unknown ] Uncertain    
[ 1775 ] [ 1778 ] Uncertain    
0950 (?) Unknown Confirmed   Radiocarbon (uncorrected)
7050 BCE (?) Unknown Confirmed   Radiocarbon (uncorrected)
7550 BCE (?) Unknown Confirmed   Radiocarbon (uncorrected)

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.

Beget J E, Nye C J, Schaefer J R, Stelling P L, 2003. Preliminary volcano-hazard assessment for Shishaldin volcano, Alaska. Alaska Dept Nat Resour Div Geol Geophys Surv, Rep Invest, 2002-4: 1-28.

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

Fournelle J H, 1988. The geology and petrology of Shishaldin volcano, Unimak Island, Aleutian arc, Alaska. Unpublished PhD thesis, John Hopkins Univ, 507 p.

Green J, Short N M, 1971. Volcanic Landforms and Surface Features: a Photographic Atlas and Glossary. New York: Springer-Verlag, 519 p.

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.

Nye C J, Keith T E C, Eichelberger J C, Miller T P, McNutt S R, Moran S, Schneider D J, Dehn J, Schaefer J R, 2002. The 1999 eruption of Shishaldin volcano, Alaska: monitoring a distant eruption. Bull Volc, 64: 507-519.

Petersen T, McNutt S R, 2007. Seismo-acoustic signals associated with degassing explosions recorded at Shishaldin Volcano, Alaska, 2003-2004. Bull Volc, 69: 527-536.

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.

Vergniolle S, Caplan-Auerbach C, 2006. Basaltic thermals and subplinian plumes: constraints from measurements at Shishaldin volcano, Alaska. Bull Volc, 68: 611-630.

The beautifully symmetrical volcano of Shishaldin is the highest and one of the most active volcanoes of the Aleutian Islands. The 2857-m-high, glacier-covered volcano is the westernmost of three large stratovolcanoes along an E-W line in the eastern half of Unimak Island. The Aleuts named the volcano Sisquk, meaning "mountain which points the way when I am lost." A steady steam plume rises from its small summit crater. Constructed atop an older glacially dissected volcano, Shishaldin is Holocene in age and largely basaltic in composition. Remnants of an older ancestral volcano are exposed on the west and NE sides at 1500-1800 m elevation. Shishaldin contains over two dozen pyroclastic cones on its NW flank, which is blanketed by massive aa lava flows. Frequent explosive activity, primarily consisting of strombolian ash eruptions from the small summit crater, but sometimes producing lava flows, has been recorded since the 18th century.