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Trident

Photo of this volcano
  • Country
  • Landform (Volc Type)
  • Last Known Eruption
  • 58.236°N
  • 155.1°W

  • 1864 m
    6115 ft

  • 312160
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

Most Recent Weekly Report: 1 March-7 March 2023 Citation IconCite this Report

AVO reported that the earthquake swarm at Trident was ongoing during 1-7 March. Daily small earthquakes with magnitudes less than 1 were recorded at a rate of about 1-5 per day. The Aviation Color Code remained at Yellow (the second lowest level on a four-color scale) and the Volcano Alert Level remained at Advisory (the second lowest level on a four-level scale).

Source: US Geological Survey Alaska Volcano Observatory (AVO)


Most Recent Bulletin Report: December 1968 (CSLP 61-68)

Large earthquakes and extensive ashfall observed; lava plug destroyed

Card 0276-0277 (09 December 1968) Ashfall covering snow extends 60 miles

"On November 21, beginning at approximately 2100Z, an extensive low-level reconaissance was performed by this agancy in a Cessna 180 aircraft. Our immediate route to the coastal area disclosed a light ash cover extending to the NW of Mount Trident. An investigation of this ash cover, on top of snow, revealed that it did originate from Mount Trident and extended for a distance of approximately 60 miles and had a fan width of approximately three miles at its termini. Medium-sized bombs were observed for an estimated radius of 1/2 mile around the cone. Mt. Trident was completely clear of its usually prominent plug. There was no sign of a recent lava flow. Smoke and steam were not an obstruction. A series of 35 mm color slides were taken of the Mount Trident cone, showing clearly the absence of the plug. Dated photographs, showing the presence and absence of the plug are on file. It is impossible to ascertain the exact period of this outburst, but it could appropriately be narrowed to the immediate 14 days preceeding the date of observation.

"The continued reconnaisance of Cape Douglas revealed no sign of surface disturbance; snow ridges were intact and no other indications of activity were discovered. The coastal beaches did appear to have suffered from an extremely high water disturbance within the recent couple of days. Driftwood was unusually high and a large amount of sea life was observed stranded. Starfish, clams, and scallops were abundant."

Card 0295-0296 (16 December 1968) Six relatively large earthquakes during 11-29 November

"The seismic telemeter network has recorded several relatively large earthquakes in the area of the Katmai National Monument during the month of November. Dates and magnitudes are as follows: 11 November, M 4.0; 20 November, M 5.1; 21 November, M 3.6; 23 November, M 4.8; 27 November, M 4.8; 29 November, M 3.9. We only locate shocks if the P-arrivals are clearly seen on three stations of the network; however, numerous smaller quakes with S-P times of the right order have been seen on the Big Mountain (BIG) and Sparevohn (SVW) stations during October. Roland Johnson from our Institute reported a very strong infrasonic signal on the 14th of November approaching the Fairbanks array system from 208°E of north (the direction from the Katmai area) at 0406 GMT. The seismic network recorded an earthquake at 0335 in SVW only with about the correct S-P time for the Katmai area (the closer station, BIG, was disconnected at that time)."

Information Contacts:
Card 0276-0277 (09 December 1968) Thomas E. Atwood, Ranger-in-Charge, Katmai National Monument, King Salmon AK, USA.
Card 0295-0296 (16 December 1968) Ed Berg, Geophysical Institute, University of Alaska, College AK, USA.

Weekly Reports - Index


2023: February | March
2022: September


1 March-7 March 2023 Citation IconCite this Report

AVO reported that the earthquake swarm at Trident was ongoing during 1-7 March. Daily small earthquakes with magnitudes less than 1 were recorded at a rate of about 1-5 per day. The Aviation Color Code remained at Yellow (the second lowest level on a four-color scale) and the Volcano Alert Level remained at Advisory (the second lowest level on a four-level scale).

Source: US Geological Survey Alaska Volcano Observatory (AVO)


22 February-28 February 2023 Citation IconCite this Report

An earthquake swarm at Trident began on 24 August 2022 and within about four days the seismic network began detecting episodes of weak seismic tremor and low frequency earthquakes. The events were initially located at depths around 25 km, but then they progressively shallowed to around 5 km by 28 August. AVO raised the Aviation Color Code for Trident to Yellow (the second lowest level on a four-color scale) and the Volcano Alert Level to Advisory (the second lowest level on a four-level scale) on 29 September due to an ongoing seismic swarm. AVO attributed the swarm to moving magma or magmatic fluids and noted that seismic swarms had previously been recorded with no subsequent eruptions. The swarm subsided and on 19 October 2022 AVO lowered both the Aviation Color Code and the Volcano Alert Level were lowered to Green and Normal, respectively, and noted that tremor had been absent since 30 September.

Beginning on 1 January 2023 seismicity again increased with earthquakes occurring at an average rate of about ten per day at depths less than 6 km. The elevated seismicity was sustained, prompting AVO raised the Aviation Color Code to Yellow and the Volcano Alert Level to Advisory on 22 February. Dozens of small earthquakes were recorded daily during 23-28 February; the largest event, a M4, was recorded during the morning of 24 February. Trident last erupted during 1953-1974.

Source: US Geological Survey Alaska Volcano Observatory (AVO)


28 September-4 October 2022 Citation IconCite this Report

AVO raised the Aviation Color Code for Trident to Yellow (the second lowest level on a four-color scale) and the Volcano Alert Level to Advisory (the second lowest level on a four-level scale) on 29 September due to an ongoing seismic swarm. The swarm began on 24 August and within about four days the seismic network began detecting episodes of weak seismic tremor and low frequency earthquakes. The events were initially located at depths around 25 km, but then they progressively shallowed to around 5 km by 28 August. Earthquakes were located 3-6 km deep since then, though some deeper events were recorded. AVO attributed the swarm to moving magma or magmatic fluids and noted that seismic swarms had previously been recorded with no subsequent eruptions.

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.

12/1968 (CSLP 61-68) Large earthquakes and extensive ashfall observed; lava plug destroyed




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


December 1968 (CSLP 61-68)

Large earthquakes and extensive ashfall observed; lava plug destroyed

Card 0276-0277 (09 December 1968) Ashfall covering snow extends 60 miles

"On November 21, beginning at approximately 2100Z, an extensive low-level reconaissance was performed by this agancy in a Cessna 180 aircraft. Our immediate route to the coastal area disclosed a light ash cover extending to the NW of Mount Trident. An investigation of this ash cover, on top of snow, revealed that it did originate from Mount Trident and extended for a distance of approximately 60 miles and had a fan width of approximately three miles at its termini. Medium-sized bombs were observed for an estimated radius of 1/2 mile around the cone. Mt. Trident was completely clear of its usually prominent plug. There was no sign of a recent lava flow. Smoke and steam were not an obstruction. A series of 35 mm color slides were taken of the Mount Trident cone, showing clearly the absence of the plug. Dated photographs, showing the presence and absence of the plug are on file. It is impossible to ascertain the exact period of this outburst, but it could appropriately be narrowed to the immediate 14 days preceeding the date of observation.

"The continued reconnaisance of Cape Douglas revealed no sign of surface disturbance; snow ridges were intact and no other indications of activity were discovered. The coastal beaches did appear to have suffered from an extremely high water disturbance within the recent couple of days. Driftwood was unusually high and a large amount of sea life was observed stranded. Starfish, clams, and scallops were abundant."

Card 0295-0296 (16 December 1968) Six relatively large earthquakes during 11-29 November

"The seismic telemeter network has recorded several relatively large earthquakes in the area of the Katmai National Monument during the month of November. Dates and magnitudes are as follows: 11 November, M 4.0; 20 November, M 5.1; 21 November, M 3.6; 23 November, M 4.8; 27 November, M 4.8; 29 November, M 3.9. We only locate shocks if the P-arrivals are clearly seen on three stations of the network; however, numerous smaller quakes with S-P times of the right order have been seen on the Big Mountain (BIG) and Sparevohn (SVW) stations during October. Roland Johnson from our Institute reported a very strong infrasonic signal on the 14th of November approaching the Fairbanks array system from 208°E of north (the direction from the Katmai area) at 0406 GMT. The seismic network recorded an earthquake at 0335 in SVW only with about the correct S-P time for the Katmai area (the closer station, BIG, was disconnected at that time)."

Information Contacts:
Card 0276-0277 (09 December 1968) Thomas E. Atwood, Ranger-in-Charge, Katmai National Monument, King Salmon AK, USA.
Card 0295-0296 (16 December 1968) Ed Berg, Geophysical Institute, University of Alaska, College AK, 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 15 confirmed Holocene eruptive periods.

1974 Jul 15 ± 45 days Confirmed Eruption Max VEI: 3

Episode 1 | Eruption Episode SW flank
1974 Jul 15 ± 45 days - Unknown Evidence from Observations: Reported

List of 3 Events for Episode 1 at SW flank

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava dome
1974 Jul 15 ± 45 days    - - - - VEI (Explosivity Index)

1968 Nov 13 - 1968 Nov 13 Confirmed Eruption Max VEI: 3

Episode 1 | Eruption Episode SW flank
1968 Nov 13 - 1968 Nov 13 Evidence from Observations: Reported

List of 5 Events for Episode 1 at SW flank

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
   - - - -    - - - - Bombs
   - - - -    - - - - Earthquakes (undefined)
1968 Nov 13    - - - - VEI (Explosivity Index)

1967 Sep 5 - 1968 Feb 25 Confirmed Eruption Max VEI: 3

Episode 1 | Eruption Episode SW flank
1967 Sep 5 - 1968 Feb 25 Evidence from Observations: Reported

List of 6 Events for Episode 1 at SW flank

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Eruption cloud
   - - - -    - - - - Lava dome
   - - - -    - - - - Ash
1967 Sep 5    - - - - VEI (Explosivity Index)
1967 Dec 18    - - - - VEI (Explosivity Index)

1966 Jul 2 (?) ± 182 days Confirmed Eruption Max VEI: 0

Episode 1 | Eruption Episode SW flank
1966 Jul 2 (?) ± 182 days - Unknown Evidence from Observations: Reported

List of 2 Events for Episode 1 at SW flank

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

1964 May 31 Confirmed Eruption Max VEI: 3 (?)

Episode 1 | Eruption Episode SW flank
1964 May 31 - Unknown Evidence from Observations: Reported

List of 3 Events for Episode 1 at SW flank

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
1964 May 31    - - - - VEI (Explosivity Index)

1963 Oct 17 - 1963 Nov 17 (?) Confirmed Eruption Max VEI: 3

Episode 1 | Eruption Episode SW flank
1963 Oct 17 - 1963 Nov 17 (?) Evidence from Observations: Reported

List of 3 Events for Episode 1 at SW flank

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
1963 Oct 17    - - - - VEI (Explosivity Index)

1963 Apr 1 - 1963 Apr 3 Confirmed Eruption Max VEI: 3

Episode 1 | Eruption Episode SW flank
1963 Apr 1 - 1963 Apr 3 Evidence from Observations: Reported

List of 4 Events for Episode 1 at SW flank

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion moderate
   - - - -    - - - - Ash
   - - - -    - - - - Lahar or Mudflow
1963 Apr 1    - - - - VEI (Explosivity Index)

1962 Jun 9 - 1962 Jun 9 Confirmed Eruption Max VEI: 3

Episode 1 | Eruption Episode SW flank
1962 Jun 9 - 1962 Jun 9 Evidence from Observations: Reported

List of 4 Events for Episode 1 at SW flank

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion moderate
   - - - -    - - - - Ash
   - - - -    - - - - Earthquakes (undefined) Before.
1962 Jun 9    - - - - VEI (Explosivity Index)

1961 Jun 30 (?) Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode SW flank (1100 m)
1961 Jun 30 (?) - Unknown Evidence from Observations: Reported

List of 4 Events for Episode 1 at SW flank (1100 m)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
   - - - -    - - - - Earthquakes (undefined) Before.
1961 Jun 30
(?)
   - - - - VEI (Explosivity Index)

1957 Jul 2 ± 182 days - 1960 Aug 10 (?) Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode SW flank
1957 Jul 2 ± 182 days - 1960 Aug 10 (?) Evidence from Observations: Reported

List of 3 Events for Episode 1 at SW flank

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
1957    - - - - VEI (Explosivity Index)

1956 Sep 8 - 1956 Sep 9 Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode Volcano Uncertain: attributed to Trident
1956 Sep 8 - 1956 Sep 9 Evidence from Unknown

List of 3 Events for Episode 1 at Volcano Uncertain: attributed to Trident

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
1956 Sep 8    - - - - VEI (Explosivity Index)

1953 Feb 15 - 1954 Oct 5 (?) Confirmed Eruption Max VEI: 3

Episode 1 | Eruption Episode SW flank (1100 m)
1953 Feb 15 - 1954 Oct 5 (?) Evidence from Observations: Reported

List of 6 Events for Episode 1 at SW flank (1100 m)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
   - - - -    - - - - Lava dome
   - - - -    - - - - Ash
   - - - -    - - - - Volcanic "smoke"
1953 Feb 15    - - - - VEI (Explosivity Index)

1950 Jul 2 - 1950 Aug 18 Confirmed Eruption Max VEI: 2 (?)

Episode 1 | Eruption Episode Volcano Uncertain: attributed to Trident
1950 Jul 2 - 1950 Aug 18 Evidence from Unknown

List of 3 Events for Episode 1 at Volcano Uncertain: attributed to Trident

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
1950 Jul 2    - - - - VEI (Explosivity Index)

1949 Jun Confirmed Eruption  

Episode 1 | Eruption Episode
1949 Jun - Unknown Evidence from Observations: Reported

1913 Sep Confirmed Eruption Max VEI: 1

Episode 1 | Eruption Episode
1913 Sep - Unknown Evidence from Observations: Reported

List of 1 Events for Episode 1

Start Date End Date Event Type Event Remarks
1913 Sep    - - - - VEI (Explosivity Index)
Deformation History

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


Deformation during 1995 - 2010 [Uplift; Observed by InSAR]

Start Date: 1995 Stop Date: 2010 Direction: Uplift Method: InSAR
Magnitude: Unknown Spatial Extent: 20.00 km Latitude: 58.000 Longitude: -155.000

Remarks: A deformation signal near Martin, Mageik, and Trident volcanoes has been observed with InSAR. There is a gap in InSAR data coverage between 2000 and 2004, but the uplift is likely continuous.

Figure (see Caption)

Averaged deformation images of the Mount Martin?Mount Mageik area produced by stacking high- quality ERS-1 and ERS-2 interferograms for 1995?2000 from two ascending tracks, 021 and 250. Ellipse outlines an area of subsidence near Novarupta dome. A full cycle of colors (i.e., one interferometric fringe) represents 28 mm/year of LOS surface displacement. Areas of loss of InSAR coherence are not colored. See Fig. 6.197 for meanings of labels

From: Lu and Dzurisin 2014.


Reference List: Lu and Dzurisin 2014; Lu et al. 1997.

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

Lu, Z., R. Fatland, M. Wyss, S. Li, J. Eichelberger, and K. Dean.,, 1997. Deformation of Volcanic Vents Detected by ERS 1 SAR Interferometry, Katmai National Park, Alaska,. Geophysical Research Letters, 24, 695 698.

Emission History

There is no Emissions History data available for Trident.

Photo Gallery

The summit crater of glacier-covered Mount Mageik appears in the foreground of this 1978 view looking NE across Katmai Pass to Trident volcano. These two volcanoes stand guard at the head of the Valley of Ten Thousand Smokes. Mageik's young crater contains a shallow turbulent lake. The fresh, black lava flows descending the SW flank of Trident volcano were emplaced in a series of eruptions during 1953-1966.

Copyrighted photo by Katia and Maurice Krafft, 1978.
A blocky andesitic lava flow, its margins marked by prominent flow levees, descends the SW flank of Trident volcano in Katmai National Park, Alaska. The lava flow, seen here from the WSW in 1978, was part of a series of eruptions from 1953 to 1968 that constructed the snow-covered cone in the background. The lava flows diverge around the lighter-colored surface of an older lava dome at the right center.

Copyrighted photo by Katia and Maurice Krafft, 1978.
The prominent cone in the center of the photo was constructed during a series of eruptions from 1953 to 1968. Following the emission of four lobate lava flows from 1953 to 1960 that traveled up to 4.5 km from the vent, the cone grew to heights of 400-800 m above the sloping SW flank of Trident. A shallow, 250-m-wide crater caps the cone.

Copyrighted photo by Katia and Maurice Krafft, 1978.
Trident, seen here from Baked Mountain to its NW, was initially named for its three prominent summits. A series of eruptions from 1953 until 1968 constructed a fourth cone, which forms the smoother peak to the right. As many as 23 lava domes are found in the Trident volcanic complex. The 1912 Novarupta lava dome is visible to the lower center.

Photo by Game McGimsey (U.S. Geological Survey, Alaska Volcano Observatory).
GVP Map Holdings

Maps are not currently available due to technical issues.

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.

Smithsonian Sample Collections Database

The following 6 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 117233-92 Volcanic Rock -- --
NMNH 117233-93 Volcanic Rock -- --
NMNH 117233-94 Pumice -- --
NMNH 117233-95 Volcanic Ash -- --
NMNH 117233-97 Dacite Mt. Cerberus (dome) --
NMNH 117233-98 Dacite Falling Mt. (dome) --
External Sites