Iliamna

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  • Country
  • Subregion Name
  • Primary Volcano Type
  • Last Known Eruption
  • 60.032°N
  • 153.09°W

  • 3053 m
    10014 ft

  • 313020
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

9 January-15 January 2013

On 9 January, AVO reported that unrest at Iliamna had decreased over the past several months, reaching background levels. The Volcano Alert Level was lowered to Normal and the Aviation Color Code was lowered to Green. The report also noted that occasional small earthquakes had continued, but at a greatly reduced rate and magnitude relative to the peak of unrest in March 2012. Steam and sulfur gas emissions continued to be observed from sites near the summit during periods of favorable meteorological conditions, not unusual at Iliamna.

Source: US Geological Survey Alaska Volcano Observatory (AVO)



 Available Weekly Reports


2013: January
2012: March | October


9 January-15 January 2013

On 9 January, AVO reported that unrest at Iliamna had decreased over the past several months, reaching background levels. The Volcano Alert Level was lowered to Normal and the Aviation Color Code was lowered to Green. The report also noted that occasional small earthquakes had continued, but at a greatly reduced rate and magnitude relative to the peak of unrest in March 2012. Steam and sulfur gas emissions continued to be observed from sites near the summit during periods of favorable meteorological conditions, not unusual at Iliamna.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


24 October-30 October 2012

AVO reported that during 24-30 October seismicity at Iliamna remained slightly elevated. Clear satellite and web camera views showed nothing unusual. The Alert Level remained at Advisory and the Aviation Color Code remained at Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


28 March-3 April 2012

AVO reported that during 28 March-3 April seismicity at Iliamna remained above background levels, although just slightly, during 25-27 March. When not obscured by clouds, satellite and web camera views showed nothing unusual. The Alert Level remained at Advisory and the Aviation Color Code remained at Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


21 March-27 March 2012

AVO reported that during 21-27 March seismicity at Iliamna remained above background levels, although just slightly during 25-27 March. When not obscured by clouds, satellite and web camera views showed nothing unusual. The Alert Level remained at Advisory and the Aviation Color Code remained at Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


14 March-20 March 2012

AVO reported that during 9-20 March seismicity at Iliamna was above background levels. Satellite images acquired during 9-16 March showed a plume drifting 56 km downwind that was likely water vapor. The report noted that long-lived fumaroles at the summit of Iliamna frequently produced visible plumes, but the current plume appeared to be more robust than usual. Scientists aboard an overflight on 17 March observed vigorous and plentiful fumaroles at the summit, consistent with the elevated gas emissions. Gas measurements indicated that the volcano was emitting elevated levels of sulfur dioxide and carbon dioxide. The Alert Level remained at Advisory and the Aviation Color Code remained at Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


7 March-13 March 2012

AVO reported that earthquake activity had steadily increased at Iliamna during the past three months. On 9 March AVO increased the Alert Level to Advisory and the Aviation Color Code to Yellow. The report noted that the current activity was characterized by numerous earthquakes that had varied in their number and magnitude over the past week.

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
[ 1987 Mar 19 ] [ 1987 May 2 ] Discredited    
[ 1978 Nov 7 ] [ 1978 Nov 7 ] Discredited    
[ 1953 Mar 1 ] [ Unknown ] Uncertain 2  
[ 1952 ] [ Unknown ] Uncertain    
[ 1947 Jun ] [ Unknown ] Uncertain    
[ 1933 May 5 ] [ Unknown ] Uncertain    
1876 Unknown Confirmed 3 Historical Observations
1867 Unknown Confirmed 2 Historical Observations
[ 1843 ] [ Unknown ] Uncertain    
[ 1793 ] [ Unknown ] Uncertain    
[ 1786 ] [ Unknown ] Uncertain    
1778 1779 Confirmed   Historical Observations
[ 1768 ] [ Unknown ] Uncertain    
1650 (?) Unknown Confirmed   Radiocarbon (uncorrected)
0450 BCE (?) Unknown Confirmed   Radiocarbon (uncorrected)
2050 BCE (?) Unknown Confirmed 4 Radiocarbon (uncorrected) Upper NE flank
5050 BCE (?) Unknown Confirmed 4 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.

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

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

Huggel C, Caplan-Auerbach J, Waythomas C F, Wessels R L, 2007. Monitoring and modeling ice-rock avalanches from ice-capped volcanoes: a case study of frequent large avalanches of Iliamna volcano, Alaska. J Volc Geotherm Res, 168: 114-136.

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.

Riehle J R, Waitt R B, Meyer C E, Calk L C, 1998. Age of formation of Kaguyak caldera, eastern Aleutian arc, Alaska, estimated by tephrochronology. In: Gray J E, Riehle J R (eds) {Geologic studies in Alaska by the U.S. Geological Survey, 1996}, US Geol Surv Prof Pap, 1595: 161-168.

Roman D C, Power J A, Moran S C, Cashman K V, Doukas M P, Neal C A, Gerlach T M, 2004. Evidence for dike emplacement beneath Iliamna volcano, Alaska in 1996. J Volc Geotherm Res, 130: 265-284.

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.

Waythomas C F, Miller T P, 1999. Preliminary volcano-hazard assessment for Iliamna volcano, Alaska. U S Geol Surv Open-File Rpt, 99-373: 1-31.

Waythomas C F, Miller T P, Beget J E, 2000. Record of late Holocene debris avalanches and lahars at Iliamna volcano, Alaska. J Volc Geotherm Res, 104: 97-130.

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

Iliamna is a prominent, 3053-m-high glacier-covered stratovolcano in Lake Clark National Park on the western side of Cook Inlet, about 225 km SW of Anchorage. Its flat-topped summit is flanked on the south, along a 5-km-long ridge, by the prominent North and South Twin Peaks, satellitic lava dome complexes. The Johnson Glacier dome complex lies on the NE flank. Steep headwalls on the southern and eastern flanks expose an inaccessible cross-section of the volcano. Major glaciers radiate from the summit, and valleys below the summit contain debris-avalanche and lahar deposits. Only a few major Holocene explosive eruptions have occurred from the deeply dissected volcano, which lacks a distinct crater. Most of the reports of historical eruptions may represent plumes from vigorous fumaroles east and SE of the summit, which are often mistaken for eruption columns (Miller et al., 1998). Eruptions producing pyroclastic flows have been dated at as recent as about 300 and 140 years ago (into the historical period), and elevated seismicity accompanying dike emplacement beneath the volcano was recorded in 1996.