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Seguam

Photo of this volcano
  • Country
  • Volcanic Region
  • Landform | Volc Type
  • Last Known Eruption
  • 52.315°N
  • 172.51°W

  • 1,054 m
    3,458 ft

  • 311180
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number


Most Recent Bulletin Report: August 1993 (BGVN 18:08) Citation IconCite this Report

Ash eruption to 2,500 m altitude

On 19 August, U.S. Coast Guard observers reported that Pyre Peak . . . was continuing to erupt from a vent ~180 m below the summit. A dark ash plume over the volcano that day reached an altitude of 2,500 m and drifted ESE. No reports of ashfall in the sparsely populated region were received. U.S. Coast Guard observers reported that Pyre Peak was continuing to erupt in late August, but poor weather conditions prevented observers from confirming continued activity through 3 September. Frequent poor weather and limited air traffic combine to make tracking of activity at this remote island volcano difficult.

Information Contacts: AVO.

The Global Volcanism Program has no Weekly Reports available for Seguam.

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.

03/1977 (NSEB 02:03) Lava fountaining from a 1-km-long rift seen on 6 March

12/1992 (BGVN 17:12) Small ash eruptions

05/1993 (BGVN 18:05) Ash eruptions reported

07/1993 (BGVN 18:07) Ash eruptions to 2,400 m height; lava flow

08/1993 (BGVN 18:08) Ash eruption to 2,500 m altitude




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


March 1977 (NSEB 02:03) Citation IconCite this Report

Lava fountaining from a 1-km-long rift seen on 6 March

Jürgen Kienle reported that on 6 March at about 0400, the crew of the USCG Cutter Mellon observed and photographed eruptive activity at the 750-m level of Pyre Peak, Seguam Island. Eight lava fountains rising to an estimated 90 m were observed along a l-km radial rift 2.5 km SW of Pyre Peak summit. Activity appeared to be progressing NE (towards the summit).

A lava flow formed and divided into two tongues. The larger was approximately 2.5 km long and l km wide. The smaller moved toward the S, and was approximately l km long and 0.5 km wide. Three dense black clouds were erupted from the vent during 2 hours of observation, after which the Mellon departed.

The nearest short-period seismometers, 225 km to the E (Nikolski), and 300 km to the W (Adak), were too far away to register any unusual earthquake activity.

Thomas Miller reported that on 8 March, a Reeve Aleutian Airlines flight passed over Seguam at low altitude. The pilot reported that lava effusion and fountaining had ended, but that a considerable amount of steam, possibly containing some ash, was being emitted from the fissure. Lava flows had not reached the sea. Poor weather during much of the year hampers aerial observation.

Several other ship reports of eruptions in the area have been received in the past several years. Seguam is uninhabited.

Information Contacts: J. Kienle, Univ. of Alaska; T. Miller, USGS, Anchorage.


December 1992 (BGVN 17:12) Citation IconCite this Report

Small ash eruptions

Small ash eruptions from a satellite cone 1.5 km S of the W caldera's central cone (Pyre Peak) (figure 1) were observed on 27 and 30 December 1992 by the U.S. Coast Guard . . . . Activity on the 27th consisted of an ash plume that extended 24 km N from the island at 1,200 m altitude. On 30 December, discrete explosions ejected ash to several hundred meters height. Ash fell S of the vent, which appears to be located near the N end of a line of lava fountains observed during the 1977 eruption. The vent site consists of a cluster of cinder cones and craters, which was probably the source of a prehistoric basaltic lava field covering ~21 km2.

Figure (see Caption) Figure 1. Topographic map of Seguam Island showing the area of December 1992 activity (dot S of Pyre Peak). The line SE from the vent site represents the 1977 lava fountains, and the outline shows the 1977 lava flows. Courtesy of AVO.

Information Contacts: Michael Doukas, USGS Anchorage.


May 1993 (BGVN 18:05) Citation IconCite this Report

Ash eruptions reported

A small ash burst, rising through clouds near Pyre Peak, was reported by the U.S. Coast Guard on 28 May. A plume to 3 km altitude was reported on 2 June by the NWS, but it is not known if the plume contained ash.

Information Contacts: AVO.


July 1993 (BGVN 18:07) Citation IconCite this Report

Ash eruptions to 2,400 m height; lava flow

Heavy ash eruptions rising 900-1,200 m were reported the morning of 31 July by the U.S. Coast Guard. A lava flow was also noted. According to these observers, the volcano was still erupting sporadically on 10 August, with light- to dark-gray ash plumes rising 2,400 m above the summit. Reports from Atka Island (~110 km W) indicate that weather conditions have frequently prevented observations.

Information Contacts: AVO.


August 1993 (BGVN 18:08) Citation IconCite this Report

Ash eruption to 2,500 m altitude

On 19 August, U.S. Coast Guard observers reported that Pyre Peak . . . was continuing to erupt from a vent ~180 m below the summit. A dark ash plume over the volcano that day reached an altitude of 2,500 m and drifted ESE. No reports of ashfall in the sparsely populated region were received. U.S. Coast Guard observers reported that Pyre Peak was continuing to erupt in late August, but poor weather conditions prevented observers from confirming continued activity through 3 September. Frequent poor weather and limited air traffic combine to make tracking of activity at this remote island volcano difficult.

Information Contacts: AVO.

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 11 confirmed Holocene eruptive periods.

1993 May 28 - 1993 Aug 31 (in or after) Confirmed Eruption VEI: 2

Episode 1 | Eruption Near Pyre Peak
1993 May 28 - 1993 Aug 31 (in or after) Evidence from Observations: Reported

List of 4 Events for Episode 1 at Near Pyre Peak

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
   - - - -    - - - - Ash
1993 May 28    - - - - VEI (Explosivity Index)

1992 Dec 27 - 1992 Dec 30 Confirmed Eruption VEI: 2

Episode 1 | Eruption Pyre Peak (1.5 km south of summit)
1992 Dec 27 - 1992 Dec 30 Evidence from Observations: Reported

List of 3 Events for Episode 1 at Pyre Peak (1.5 km south of summit)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
1992 Dec 27    - - - - VEI (Explosivity Index)

1977 Mar 6 - 1977 Mar 8 (?) Confirmed Eruption VEI: 1

Episode 1 | Eruption Pyre Peak (2.5 km SE of summit)
1977 Mar 6 - 1977 Mar 8 (?) Evidence from Observations: Reported

List of 5 Events for Episode 1 at Pyre Peak (2.5 km SE of summit)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava fountains
   - - - -    - - - - Lava flow
   - - - -    - - - - Lava flow Entered water.
1977 Mar 6    - - - - VEI (Explosivity Index)

[ 1927 ] Uncertain Eruption

Episode 1 | Eruption
1927 - Unknown Evidence from Unknown

List of 1 Events for Episode 1

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

1902 Confirmed Eruption VEI: 3

Episode 1 | Eruption
1902 - Unknown Evidence from Observations: Reported

List of 2 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
1902    - - - - VEI (Explosivity Index)

1892 Apr 15 ± 45 days Confirmed Eruption VEI: 3

Episode 1 | Eruption
1892 Apr 15 ± 45 days - Unknown Evidence from Observations: Reported

List of 4 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
   - - - -    - - - - Audible Sounds
1892 Apr 15 ± 45 days    - - - - VEI (Explosivity Index)

1891 Dec Confirmed Eruption VEI: 2

Episode 1 | Eruption
1891 Dec - Unknown Evidence from Observations: Reported

List of 2 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion weak or small
1891 Dec    - - - - VEI (Explosivity Index)

[ 1827 ] Uncertain Eruption

Episode 1 | Eruption
1827 - Unknown Evidence from Unknown

List of 1 Events for Episode 1

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

1786 - 1790 Confirmed Eruption  

Episode 1 | Eruption
1786 - 1790 Evidence from Observations: Reported

0250 ± 500 years Confirmed Eruption  

Episode 1 | Eruption West of Wilcox volcano
0250 ± 500 years - Unknown Evidence from Isotopic: Uranium-series

List of 1 Events for Episode 1 at West of Wilcox volcano

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Lava dome

4050 BCE ± 4000 years Confirmed Eruption VEI: 0

Episode 1 | Eruption W flank of cone in eastern caldera
4050 BCE ± 4000 years - Unknown Evidence from Isotopic: Uranium-series

List of 2 Events for Episode 1 at W flank of cone in eastern caldera

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Lava flow
4050 BCE ± 1000 years    - - - - VEI (Explosivity Index)

5100 BCE ± 2000 years Confirmed Eruption VEI: 0

Episode 1 | Eruption W flank of cone in eastern caldera
5100 BCE ± 2000 years - Unknown Evidence from Isotopic: Uranium-series

List of 2 Events for Episode 1 at W flank of cone in eastern caldera

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Lava flow
5100 BCE ± 1000 years    - - - - VEI (Explosivity Index)

7300 BCE ± 2250 years Confirmed Eruption VEI: 5 (?)

Episode 1 | Eruption Wilcox volcano
7300 BCE ± 2250 years - Unknown Evidence from Isotopic: Ar/Ar

List of 4 Events for Episode 1 at Wilcox volcano

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Pyroclastic flow
   - - - -    - - - - Avalanche Uncertain
7300 BCE ± 1000 years    - - - - VEI (Explosivity Index)
Deformation History

There is data available for 6 deformation periods. Expand each entry for additional details.


Deformation during 2005 Jul - 2007 Jul [Uplift; Observed by InSAR]

Start Date: 2005 Jul Stop Date: 2007 Jul Direction: Uplift Method: InSAR
Magnitude: Unknown Spatial Extent: 8.00 km Latitude: 52.000 Longitude: -172.000

Remarks: Uplift of the eastern caldera due to basalt injection into the magma reservoir.

Figure (see Caption)

Average line-of-sight surface displacement rate maps for Seguam during five time intervals (stages) based on the time-series shown in Fig. 5: (a) Stage 1, January 1993?October 1993, (d) Stage 2, October 1993?November 1998, (g) Stage 3, November 1998?September 2000, (j) Stage 4, September 2000?November 2005, and (m) Stage 5, November 2005?July 2007. Images 5b, 5e, 5h, 5k and 5n are corresponding best-fit model interferograms using a Mogi (1958) source with location of source in the center of the caldera (star). Images 5c, 5f, 5i, 5l and 5o are corresponding residual interferograms showing differences between observed and model interferograms.

From: Lee et al. 2013.


Reference List: Lee et al. 2013; Lu and Dzurisin 2014.

Full References:

Lee, C. W., Lu, Z., Won, J. S., Jung, H. S., & Dzurisin, D., 2013. Dynamic deformation of Seguam Island, Alaska, 1992-2008, from multi-interferogram InSAR processing. J. Volcanol. Geotherm. Res., 260: 43-51. https://doi.org/10.1016/j.jvolgeores.2013.05.009

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

Deformation during 2000 Sep - 2005 Jul [Subsidence; Observed by InSAR]

Start Date: 2000 Sep Stop Date: 2005 Jul Direction: Subsidence Method: InSAR
Magnitude: Unknown Spatial Extent: 4.00 km Latitude: 52.000 Longitude: -172.000

Remarks: Subsidence of the eastern caldera due to cooling and degassing of the upper part of the magma reservoir.

Figure (see Caption)

Average line-of-sight surface displacement rate maps for Seguam during five time intervals (stages) based on the time-series shown in Fig. 5: (a) Stage 1, January 1993?October 1993, (d) Stage 2, October 1993?November 1998, (g) Stage 3, November 1998?September 2000, (j) Stage 4, September 2000?November 2005, and (m) Stage 5, November 2005?July 2007. Images 5b, 5e, 5h, 5k and 5n are corresponding best-fit model interferograms using a Mogi (1958) source with location of source in the center of the caldera (star). Images 5c, 5f, 5i, 5l and 5o are corresponding residual interferograms showing differences between observed and model interferograms.

From: Lee et al. 2013.


Reference List: Lee et al. 2013; Lu and Dzurisin 2014.

Full References:

Lee, C. W., Lu, Z., Won, J. S., Jung, H. S., & Dzurisin, D., 2013. Dynamic deformation of Seguam Island, Alaska, 1992-2008, from multi-interferogram InSAR processing. J. Volcanol. Geotherm. Res., 260: 43-51. https://doi.org/10.1016/j.jvolgeores.2013.05.009

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

Deformation during 1998 Nov - 2000 Sep [Uplift; Observed by InSAR]

Start Date: 1998 Nov Stop Date: 2000 Sep Direction: Uplift Method: InSAR
Magnitude: Unknown Spatial Extent: 8.00 km Latitude: 52.000 Longitude: -172.000

Remarks: Uplift of the eastern caldera due to basalt injection into the magma reservoir.

Figure (see Caption)

Average line-of-sight surface displacement rate maps for Seguam during five time intervals (stages) based on the time-series shown in Fig. 5: (a) Stage 1, January 1993?October 1993, (d) Stage 2, October 1993?November 1998, (g) Stage 3, November 1998?September 2000, (j) Stage 4, September 2000?November 2005, and (m) Stage 5, November 2005?July 2007. Images 5b, 5e, 5h, 5k and 5n are corresponding best-fit model interferograms using a Mogi (1958) source with location of source in the center of the caldera (star). Images 5c, 5f, 5i, 5l and 5o are corresponding residual interferograms showing differences between observed and model interferograms.

From: Lee et al. 2013.


Reference List: Lee et al. 2013; Lu and Dzurisin 2014; Masterlark and Lu 2004.

Full References:

Lee, C. W., Lu, Z., Won, J. S., Jung, H. S., & Dzurisin, D., 2013. Dynamic deformation of Seguam Island, Alaska, 1992-2008, from multi-interferogram InSAR processing. J. Volcanol. Geotherm. Res., 260: 43-51. https://doi.org/10.1016/j.jvolgeores.2013.05.009

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

Masterlark, T., and Z. Lu,, 2004. Transient volcano deformation sources imaged with InSAR: Application to Seguam island. J. Geophys. Res., 109, B01401. https://doi.org/10.1029/2003JB002568

Deformation during 1993 Oct - 1998 Nov [Subsidence; Observed by InSAR]

Start Date: 1993 Oct Stop Date: 1998 Nov Direction: Subsidence Method: InSAR
Magnitude: Unknown Spatial Extent: 4.00 km Latitude: 52.000 Longitude: -172.000

Remarks: Subsidence of the eastern caldera due to cooling and degassing of the upper part of the magma reservoir.

Figure (see Caption)

Average line-of-sight surface displacement rate maps for Seguam during five time intervals (stages) based on the time-series shown in Fig. 5: (a) Stage 1, January 1993?October 1993, (d) Stage 2, October 1993?November 1998, (g) Stage 3, November 1998?September 2000, (j) Stage 4, September 2000?November 2005, and (m) Stage 5, November 2005?July 2007. Images 5b, 5e, 5h, 5k and 5n are corresponding best-fit model interferograms using a Mogi (1958) source with location of source in the center of the caldera (star). Images 5c, 5f, 5i, 5l and 5o are corresponding residual interferograms showing differences between observed and model interferograms.

From: Lee et al. 2013.


Reference List: Lee et al. 2013; Lu and Dzurisin 2014; Masterlark and Lu 2004.

Full References:

Lee, C. W., Lu, Z., Won, J. S., Jung, H. S., & Dzurisin, D., 2013. Dynamic deformation of Seguam Island, Alaska, 1992-2008, from multi-interferogram InSAR processing. J. Volcanol. Geotherm. Res., 260: 43-51. https://doi.org/10.1016/j.jvolgeores.2013.05.009

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

Masterlark, T., and Z. Lu,, 2004. Transient volcano deformation sources imaged with InSAR: Application to Seguam island. J. Geophys. Res., 109, B01401. https://doi.org/10.1029/2003JB002568

Deformation during 1993 Jan - 1993 Oct [Uplift; Observed by InSAR]

Start Date: 1993 Jan Stop Date: 1993 Oct Direction: Uplift Method: InSAR
Magnitude: Unknown Spatial Extent: 8.00 km Latitude: 52.000 Longitude: -172.000

Remarks: Uplift of the eastern caldera due to basalt injection into the magma reservoir.

Figure (see Caption)

Average line-of-sight surface displacement rate maps for Seguam during five time intervals (stages) based on the time-series shown in Fig. 5: (a) Stage 1, January 1993?October 1993, (d) Stage 2, October 1993?November 1998, (g) Stage 3, November 1998?September 2000, (j) Stage 4, September 2000?November 2005, and (m) Stage 5, November 2005?July 2007. Images 5b, 5e, 5h, 5k and 5n are corresponding best-fit model interferograms using a Mogi (1958) source with location of source in the center of the caldera (star). Images 5c, 5f, 5i, 5l and 5o are corresponding residual interferograms showing differences between observed and model interferograms.

From: Lee et al. 2013.


Reference List: Lee et al. 2013; Lu and Dzurisin 2014; Masterlark and Lu 2004.

Full References:

Lee, C. W., Lu, Z., Won, J. S., Jung, H. S., & Dzurisin, D., 2013. Dynamic deformation of Seguam Island, Alaska, 1992-2008, from multi-interferogram InSAR processing. J. Volcanol. Geotherm. Res., 260: 43-51. https://doi.org/10.1016/j.jvolgeores.2013.05.009

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

Masterlark, T., and Z. Lu,, 2004. Transient volcano deformation sources imaged with InSAR: Application to Seguam island. J. Geophys. Res., 109, B01401. https://doi.org/10.1029/2003JB002568

Deformation during 1992 - 2008 [Subsidence; Observed by InSAR]

Start Date: 1992 Stop Date: 2008 Direction: Subsidence Method: InSAR
Magnitude: Unknown Spatial Extent: 5.00 km Latitude: 52.000 Longitude: -173.000

Remarks: Subsidence in the western caldera due to thermoelastic compaction of young lava flows.


Reference List: Lee et al. 2013; Lu and Dzurisin 2014; Masterlark and Lu 2004.

Full References:

Lee, C. W., Lu, Z., Won, J. S., Jung, H. S., & Dzurisin, D., 2013. Dynamic deformation of Seguam Island, Alaska, 1992-2008, from multi-interferogram InSAR processing. J. Volcanol. Geotherm. Res., 260: 43-51. https://doi.org/10.1016/j.jvolgeores.2013.05.009

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

Masterlark, T., and Z. Lu,, 2004. Transient volcano deformation sources imaged with InSAR: Application to Seguam island. J. Geophys. Res., 109, B01401. https://doi.org/10.1029/2003JB002568

Emission History

There is no Emissions History data available for Seguam.

GVP Map Holdings

Maps are not currently available due to technical issues.

Smithsonian Sample Collections Database

There are no samples for Seguam in the Smithsonian's NMNH Department of Mineral Sciences Rock and Ore collection.

External Sites