Logo link to homepage

Gareloi

Photo of this volcano
  • Country
  • Primary Volcano Type
  • Last Known Eruption
  •  
  • 51.79°N
  • 178.794°W

  • 1573 m
    5161 ft

  • 311070
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number
Most Recent Weekly Report: 14 February-20 February 2024 Citation IconCite this Report

AVO reported that unrest continued at Gareloi during 14-20 February. Seismicity remained elevated and was characterized by volcanic earthquakes and semi-continuous tremor, though after 16 February levels began to decline and only periods of seismic tremor were reported. Minor steaming was identified in webcam and satellite images on 14 February. The Volcano Alert Level remained at Advisory (the second lowest level on a four-level scale) and the Aviation Color Code remained at Yellow (the second lowest color on a four-color scale).

Source: US Geological Survey Alaska Volcano Observatory (AVO)


Most Recent Bulletin Report: October 1996 (BGVN 21:10) Citation IconCite this Report

Pilot report of plume on 27 September

On 27 September the Aviation Weather Unit in Alaska received a pilot report of a minor eruption of ash and steam at Gareloi. The plume reportedly rose to 1,500 m altitude but was not visible on infrared satellite imagery suggesting it may have not ascended that high. As late as 5 December AVO had learned of no further sightings of activity at Gareloi.

Information Contacts: NOAA/NESDIS Satellite Analysis Branch (SAB), Room 401, 5200 Auth Road, Camp Springs, MD 20746, USA; Alaska Volcano Observatory (AVO), a cooperative program of a) U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508-4667, USA (URL: http://www.avo.alaska.edu/), b) Geophysical Institute, University of Alaska, PO Box 757320, Fairbanks, AK 99775-7320, USA, and c) Alaska Division of Geological & Geophysical Surveys, 794 University Ave., Suite 200, Fairbanks, AK 99709, USA.

Weekly Reports - Index


2024: February
2021: March | May | June | July


14 February-20 February 2024 Citation IconCite this Report

AVO reported that unrest continued at Gareloi during 14-20 February. Seismicity remained elevated and was characterized by volcanic earthquakes and semi-continuous tremor, though after 16 February levels began to decline and only periods of seismic tremor were reported. Minor steaming was identified in webcam and satellite images on 14 February. The Volcano Alert Level remained at Advisory (the second lowest level on a four-level scale) and the Aviation Color Code remained at Yellow (the second lowest color on a four-color scale).

Source: US Geological Survey Alaska Volcano Observatory (AVO)


7 February-13 February 2024 Citation IconCite this Report

AVO raised the Volcano Alert Level for Gareloi to Advisory (the second level on a four-level scale) and the Aviation Color Code to Yellow (the second color on a four-color scale) at 1310 on 12 February due to increased seismic activity. Seismic unrest began at 0915 on 12 February; the local seismic network recorded ongoing tremor during 12-13 February. Persistent degassing activity from a fumarole field located on the S crater continued. No additional surficial activity was observed in partly cloudy satellite and webcam images.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


28 July-3 August 2021 Citation IconCite this Report

AVO reported that the elevated seismicity first detected at Gareloi in May had continued through June and then declined to background levels. On 28 July 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)


2 June-8 June 2021 Citation IconCite this Report

AVO reported that a minor increase in seismicity was first detected at Gareloi on 19 May. Beginning on 27 May the rate and size of small volcanic earthquakes increased and was sustained at that level. On 8 June AVO raised the Aviation Color Code to Yellow and the Volcano Alert Level to Advisory based on seismicity rising above baseline levels. Sulfur dioxide emissions had been identified in satellite images the past week, though they were consistent with measurements recorded in previous years. No other changes were evident in satellite or webcam views.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


26 May-1 June 2021 Citation IconCite this Report

On 27 May AVO changed the Aviation Color Code and Volcano Alert Level for Gareloi to Green and Normal, respectively, reflecting that communication with seismic stations had been re-established, allowing for the location of earthquakes and detection of unrest.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


31 March-6 April 2021 Citation IconCite this Report

AVO reported that a loss of operation and communication with all seismic stations on Gareloi was likely due to snow cover. Both the Aviation Color Code and the Volcano Alert Level were changed to Unassigned, reflecting the lack of this data to detect unrest. The observatory noted that regional infrasound networks, lightning detection, and satellite images will be used to monitor and detected unrest.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


Bulletin Reports - Index

Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.

08/1980 (SEAN 05:08) Tephra cloud from summit crater

09/1980 (SEAN 05:09) Renewed ash emission to six kilometers

11/1980 (SEAN 05:11) Aircraft samples stratospheric plume

02/1982 (SEAN 07:02) Large plume seen on satellite imagery

08/1987 (SEAN 12:08) Narrow steaming flow-like feature

10/1996 (BGVN 21:10) Pilot report of plume on 27 September




Information is preliminary and subject to change. All times are local (unless otherwise noted)


August 1980 (SEAN 05:08) Citation IconCite this Report

Tephra cloud from summit crater

During an overflight on 8 August, USN pilot Edwin Beech saw vapor rising to about 1 km above the summit crater. The next day, a Northwest Orient Airlines pilot observed a steam and ash column that reached 10.5 km altitude and was blown NNW, away from inhabited areas. Poor weather obscured the summit for the next several days, although large eruption columns would have been visible above the cloud layer from passing aircraft.

On 13 August, USN pilots were able to see the top 300 m of the volcano. A light gray eruption cloud that appeared to originate from the NE quadrant of the summit crater rose to about 2.5 km altitude (1 km above the summit), depositing ash to the NW. Both Lt. Beech and David Evans, who operates the USGS seismic station on nearby Adak Island, felt that the summit area had changed significantly during the eruption.

By 23-24 August, the activity had declined to weak vapor emission. No lava flows have been observed. Gareloi's last reported eruption was in January 1952.

Information Contacts: T. Miller, USGS, Anchorage; Lt. E. Beech, U.S. Navy, Adak Island; D. Evans, USGS, Adak Island.


September 1980 (SEAN 05:09) Citation IconCite this Report

Renewed ash emission to six kilometers

USAF pilot Jerry Nelson observed renewed activity from Gareloi during an overflight on 17 September. As he approached the volcano at about 1600, he saw a slight wisp of vapor that grew rapidly into a dark brown ash-rich column reaching about 6 km altitude. The eruption column, which appeared to originate from the E side of the summit crater, drifted slightly N or NW. The activity was visible until Nelson left the area about 10 minutes later.

Information Contacts: T. Miller, USGS, Anchorage AK; J. Nelson, U.S. Air Force, Travis AFB, CA.


November 1980 (SEAN 05:11) Citation IconCite this Report

Aircraft samples stratospheric plume

On 10 and 11 August, SO2 from a fresh volcanic plume was detected from a research aircraft (flown by NASA under contract from the U.S. Department of Energy) at 19.2 km altitude just S of Anchorage Alaska.

Imagery returned 8 August at 1010 by the NOAA 6 satellite shows a high-altitude plume appearing to originate from the vicinity of Gareloi. Using a drift rate of 30 km/hour, Los Alamos National Laboratory (LANL) personnel calculated that the eruption that produced this plume had probably ended about 10 hours earlier. Later visual and infrared images show the plume moving toward the Anchorage area, about 2,000 km from Gareloi, at a rate that could have brought it to the sampling area by 10 August. The eruption column seen emerging from Gareloi 9 August by a commercial pilot was also present on satellite images, but clearly was not large enough and did not reach a high enough altitude to have been the source of the material sampled 10-11 August. Wind conditions also preclude the 7 August eruption clouds from Mt. St. Helens as a source for SO2 in the Anchorage area at this time.

Further Reference. Sedlacek, W.A., Mroz, E.J., and Heiken, G., 1981, Stratospheric sulfate from the Gareloi eruption, 1980: contribution to the "ambient" aerosol by a poorly documented volcanic eruption: Geophysical Research Letters, v. 8, p. 761-764.

Information Contacts: W. Sedlacek, G. Heiken, and E. Mroz, LANL.


February 1982 (SEAN 07:02) Citation IconCite this Report

Large plume seen on satellite imagery

Infrared imagery from the NOAA 7 polar orbiting satellite 15 January at 1402 showed an apparent eruption cloud blowing E from the vicinity of Gareloi (figure 1). Analysis of this image yielded a cloud top temperature of -36°C, indicating an altitude of 7-9 km. No eruption clouds were present on images the two previous days and the following day, nor was any activity evident on imagery 24 January, or 3 and 11 February. No ashfall was reported on Adak Island (130 km to the E) or Shemya Island (500 km to the WNW). Navy pilots plan to photograph Gareloi in the near future, for comparison with photos taken during and after its August-September 1980 eruption.

Figure (see Caption) Figure 1. Infrared image returned 15 January 1982 at 1402 by the NOAA 7 polar orbiting satellite. A bright white plume, at left-center, drifts ESE. Dark ripples near the plume and at right-center indicate the position of islands in the Aleutian chain.

The seismic network on Adak Island recorded an mb 3.2-3.3 earthquake on 15 January at 0521. No unique hypocenter can be determined for this event, but one of the two possible solutions places it directly under Gareloi. This shock was substantially larger than the mb 2.6 event that accompanied the February 1974 eruption of Great Sitkin, which produced a 3-km plume. Additional events were recorded the following week that may also be centered in the vicinity of Gareloi. An infrasound array at College, Alaska (about 2,200 km NE of Gareloi) recorded no acoustic wave associated with the eruption.

Information Contacts: J. Kienle, Univ. of Alaska; S. Billington, NOAA/CIRES, Univ. of Colorado; P. Mutschlecner, LANL.


August 1987 (SEAN 12:08) Citation IconCite this Report

Narrow steaming flow-like feature

On 4 September 1987 at 1500, flight engineer George Wooliver (Reeve Aleutian Airways) observed a narrow flow-like feature that had descended the E flank, from the N crater rim at 1,500 m elevation to at least 1,100 m. A thick cloud cover obscured it below that level. Steam was rising as much as 100 m above the flow feature along its entire visible length. Steaming from the crater appeared more vigorous than usual.

Information Contacts: J. Reeder, ADGGS.


October 1996 (BGVN 21:10) Citation IconCite this Report

Pilot report of plume on 27 September

On 27 September the Aviation Weather Unit in Alaska received a pilot report of a minor eruption of ash and steam at Gareloi. The plume reportedly rose to 1,500 m altitude but was not visible on infrared satellite imagery suggesting it may have not ascended that high. As late as 5 December AVO had learned of no further sightings of activity at Gareloi.

Information Contacts: NOAA/NESDIS Satellite Analysis Branch (SAB), Room 401, 5200 Auth Road, Camp Springs, MD 20746, USA; Alaska Volcano Observatory (AVO), a cooperative program of a) U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508-4667, USA (URL: http://www.avo.alaska.edu/), b) Geophysical Institute, University of Alaska, PO Box 757320, Fairbanks, AK 99775-7320, USA, and c) Alaska Division of Geological & Geophysical Surveys, 794 University Ave., Suite 200, Fairbanks, AK 99709, USA.

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Eruptive History

There is data available for 12 confirmed Holocene eruptive periods.

[ 1996 Sep 27 ] Uncertain Eruption

Episode 1 | Eruption Episode
1996 Sep 27 - Unknown Evidence from Unknown

List of 3 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion Uncertain
   - - - -    - - - - Ash Uncertain
1996 Sep 27    - - - - VEI (Explosivity Index)

1989 Aug 17 Confirmed Eruption Max VEI: 1

Episode 1 | Eruption Episode
1989 Aug 17 - Unknown Evidence from Observations: Reported

List of 2 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
1989 Aug 17    - - - - VEI (Explosivity Index)

1987 Sep 4 Confirmed Eruption Max VEI: 1 (?)

Episode 1 | Eruption Episode
1987 Sep 4 - Unknown Evidence from Observations: Reported

List of 3 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Pyroclastic flow Uncertain
   - - - -    - - - - Lava flow
1987 Sep 4    - - - - VEI (Explosivity Index)

1982 Jan 15 - 1982 Jan 15 Confirmed Eruption Max VEI: 3

Episode 1 | Eruption Episode
1982 Jan 15 - 1982 Jan 15 Evidence from Observations: Reported

List of 4 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Eruption cloud
   - - - -    - - - - Earthquakes (undefined)
1982 Jan 15    - - - - VEI (Explosivity Index)

1980 Aug 7 - 1980 Sep 17 Confirmed Eruption Max VEI: 3 (?)

Episode 1 | Eruption Episode
1980 Aug 7 - 1980 Sep 17 Evidence from Observations: Reported

List of 3 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
1980 Aug 7    - - - - VEI (Explosivity Index)

1952 Jan 17 Confirmed Eruption Max VEI: 2 (?)

Episode 1 | Eruption Episode
1952 Jan 17 - Unknown Evidence from Observations: Reported

List of 2 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Ash
1952 Jan 17    - - - - VEI (Explosivity Index)

1950 Jul 2 ± 182 days - 1951 Jul 2 ± 182 days Confirmed Eruption Max VEI: 1

Episode 1 | Eruption Episode
1950 Jul 2 ± 182 days - 1951 Jul 2 ± 182 days Evidence from Observations: Reported

List of 3 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Phreatic activity
   - - - -    - - - - Ash moderate
1950    - - - - VEI (Explosivity Index)

1929 Apr - 1930 Confirmed Eruption Max VEI: 3

Episode 1 | Eruption Episode SE flank fissure (near summit to sea)
1929 Apr - 1930 Evidence from Observations: Reported

List of 11 Events for Episode 1 at SE flank fissure (near summit to sea)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Phreatic activity
   - - - -    - - - - Lava flow
   - - - -    - - - - Lava flow Entered water.
   - - - -    - - - - Ash
   - - - -    - - - - Lapilli
   - - - -    - - - - Pumice
   - - - -    - - - - Earthquakes (undefined)
   - - - -    - - - - Crater Parasitic.
   - - - -    - - - - Property Damage
1929 Apr    - - - - VEI (Explosivity Index)

[ 1927 ] Uncertain Eruption

Episode 1 | Eruption Episode
1927 - Unknown Evidence from Unknown

List of 1 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Volcanic "smoke"

1922 Confirmed Eruption Max VEI: 3

Episode 1 | Eruption Episode
1922 - Unknown Evidence from Observations: Reported

List of 2 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
1922    - - - - VEI (Explosivity Index)

1873 Confirmed Eruption Max VEI: 2 (?)

Episode 1 | Eruption Episode
1873 - Unknown Evidence from Observations: Reported

List of 1 Events for Episode 1

Start Date End Date Event Type Event Remarks
1873    - - - - VEI (Explosivity Index)

[ 1828 - 1829 ] Uncertain Eruption

Episode 1 | Eruption Episode
1828 - 1829 Evidence from Unknown

List of 2 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Volcanic "smoke"
1828    - - - - VEI (Explosivity Index)

1792 Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode
1792 - Unknown Evidence from Observations: Reported

List of 3 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Lava flow
   - - - -    - - - - Ash
1792    - - - - VEI (Explosivity Index)

1791 Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode
1791 - Unknown Evidence from Observations: Reported

List of 2 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion weak or small
1791    - - - - VEI (Explosivity Index)

1790 Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode
1790 - Unknown Evidence from Observations: Reported

List of 2 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion weak or small
1790    - - - - VEI (Explosivity Index)

[ 1760 ] Uncertain Eruption

Episode 1 | Eruption Episode
1760 - Unknown Evidence from Unknown

List of 1 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Volcanic "smoke"
Deformation History

There is data available for 1 deformation periods. Expand each entry for additional details.


Deformation during 1995 - 2009 [Subsidence; Observed by InSAR]

Start Date: 1995 Stop Date: 2009 Direction: Subsidence Method: InSAR
Magnitude: Unknown Spatial Extent: 1.00 km Latitude: 52.000 Longitude: -179.000

Remarks: Subsidence of the south flank near 1929 vent area is likely due to contraction and compaction of surface deposits.

Figure (see Caption)

a?e Selected interferograms of Mount Gareloi produced from Envisat images acquired on ascending track 022 during 2004?2009. f Average interferogram produced by stacking all available interferograms from this track. A full cycle of colors (i.e., one interferometric fringe) represents 2.83 cm of surface displacement along the LOS. Areas of coherence loss are not colored

From: Lu and Dzurisin 2014.


Reference List: Lu and Dzurisin 2014.

Full References:

Lu Z, Dzurisin D, 2014. InSAR imaging of Aleutian volcanoes: monitoring a volcanic arc from space. Springer-Verlag Berlin Heidelberg. https://doi.org/10.1007/978-3-642-00348-6

Emission History

There is no Emissions History data available for Gareloi.

GVP Map Holdings

The maps shown below have been scanned from the GVP map archives and include the volcano on this page. Clicking on the small images will load the full 300 dpi map. Very small-scale maps (such as world maps) are not included. The maps database originated over 30 years ago, but was only recently updated and connected to our main database. We welcome users to tell us if they see incorrect information or other problems with the maps; please use the Contact GVP link at the bottom of the page to send us email.

Smithsonian Sample Collections Database

The following 35 samples associated with this volcano can be found in the Smithsonian's NMNH Department of Mineral Sciences collections, and may be availble for research (contact the Rock and Ore Collections Manager). Catalog number links will open a window with more information.

Catalog Number Sample Description Lava Source Collection Date
NMNH 118210-1 Lapilli tephra -- 17 Sep 2015
NMNH 118210-10 Picrite -- 17 Sep 2015
NMNH 118210-11 Lapilli tephra -- 17 Sep 2015
NMNH 118210-12 Lapilli tephra -- 17 Sep 2015
NMNH 118210-13 Volcanic Ash -- 17 Sep 2015
NMNH 118210-14 Lapilli tephra -- 17 Sep 2015
NMNH 118210-15 Coarse ash -- 17 Sep 2015
NMNH 118210-16 Lapilli tephra -- 18 Sep 2015
NMNH 118210-17 Lapilli tephra -- 18 Sep 2015
NMNH 118210-18 Lapilli tephra -- 18 Sep 2015
NMNH 118210-19 Coarse ash -- 18 Sep 2015
NMNH 118210-2 Volcanic Ash -- 17 Sep 2015
NMNH 118210-20 Coarse ash -- 18 Sep 2015
NMNH 118210-21 Scoriaceous agglutinate -- 19 Sep 2015
NMNH 118210-22 Scoriaceous Basalt -- 19 Sep 2015
NMNH 118210-23 Ash; Scoria -- 19 Sep 2015
NMNH 118210-24 Basalt -- 19 Sep 2015
NMNH 118210-25 Volcanic Ash -- 19 Sep 2015
NMNH 118210-26 Lapilli tephra -- 19 Sep 2015
NMNH 118210-27 Lapilli tephra -- 19 Sep 2015
NMNH 118210-28 Lapilli tephra -- 19 Sep 2015
NMNH 118210-29 Lapilli tephra -- 19 Sep 2015
NMNH 118210-3 Lapilli tephra -- 17 Sep 2015
NMNH 118210-30 Coarse ash -- 19 Sep 2015
NMNH 118210-31 Coarse ash -- 19 Sep 2015
NMNH 118210-32 Lapilli tephra -- 19 Sep 2015
NMNH 118210-33 Lapilli tephra -- 19 Sep 2015
NMNH 118210-34 Lapilli tephra -- 17 Sep 2015
NMNH 118210-35 Basalt -- 17 Sep 2015
NMNH 118210-4 Tephra -- 17 Sep 2015
NMNH 118210-5 Lapilli tephra -- 17 Sep 2015
NMNH 118210-6 Volcanic Ash -- 17 Sep 2015
NMNH 118210-7 Lapilli tephra -- 17 Sep 2015
NMNH 118210-8 Fine ash -- 17 Sep 2015
NMNH 118210-9 Fine ash -- 17 Sep 2015
External Sites