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)
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.
2023: February
| March
2022: September
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)
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)
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)
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.
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.
Cones |
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Feature Name | Feature Type | Elevation | Latitude | Longitude |
East Trident | Stratovolcano | 1832 m | 58° 15' 0" N | 155° 4' 0" W |
Southwest Trident | Stratovolcano | 58° 14' 0" N | 155° 7' 0" W | |
Trident I | Stratovolcano | 1864 m | 58° 14' 0" N | 155° 6' 0" W |
West Trident | Stratovolcano | 1708 m | 58° 14' 30" N | 155° 8' 0" W |
Domes |
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Feature Name | Feature Type | Elevation | Latitude | Longitude |
Cerberus, Mount | Dome | 1098 m | 58° 14' 47" N | 155° 11' 56" W |
Falling Mountain | Dome | 1160 m | 58° 15' 20" N | 155° 10' 19" W |
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There is data available for 15 confirmed Holocene eruptive periods.
1974 Jul 15 ± 45 days Confirmed Eruption VEI: 3
Episode 1 | Eruption | SW flank | ||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1974 Jul 15 ± 45 days - Unknown | Evidence from Observations: Reported | ||||||||||||||||||||||||
List of 3 Events for Episode 1 at SW flank
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1968 Nov 13 - 1968 Nov 13 Confirmed Eruption VEI: 3
Episode 1 | Eruption | SW flank | ||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1968 Nov 13 - 1968 Nov 13 | Evidence from Observations: Reported | ||||||||||||||||||||||||||||||||||
List of 5 Events for Episode 1 at SW flank
|
1967 Sep 5 - 1968 Feb 25 Confirmed Eruption VEI: 3
Episode 1 | Eruption | SW flank | |||||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1967 Sep 5 - 1968 Feb 25 | Evidence from Observations: Reported | |||||||||||||||||||||||||||||||||||||||
List of 6 Events for Episode 1 at SW flank
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1966 Jul 2 (?) ± 182 days Confirmed Eruption VEI: 0
Episode 1 | Eruption | SW flank | |||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1966 Jul 2 (?) ± 182 days - Unknown | Evidence from Observations: Reported | |||||||||||||||||||
List of 2 Events for Episode 1 at SW flank
|
1964 May 31 Confirmed Eruption VEI: 3 (?)
Episode 1 | Eruption | SW flank | ||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1964 May 31 - Unknown | Evidence from Observations: Reported | ||||||||||||||||||||||||
List of 3 Events for Episode 1 at SW flank
|
1963 Oct 17 - 1963 Nov 17 (?) Confirmed Eruption VEI: 3
Episode 1 | Eruption | SW flank | ||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1963 Oct 17 - 1963 Nov 17 (?) | Evidence from Observations: Reported | ||||||||||||||||||||||||
List of 3 Events for Episode 1 at SW flank
|
1963 Apr 1 - 1963 Apr 3 Confirmed Eruption VEI: 3
Episode 1 | Eruption | SW flank | |||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1963 Apr 1 - 1963 Apr 3 | Evidence from Observations: Reported | |||||||||||||||||||||||||||||
List of 4 Events for Episode 1 at SW flank
|
1962 Jun 9 - 1962 Jun 9 Confirmed Eruption VEI: 3
Episode 1 | Eruption | SW flank | |||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1962 Jun 9 - 1962 Jun 9 | Evidence from Observations: Reported | |||||||||||||||||||||||||||||
List of 4 Events for Episode 1 at SW flank
|
1961 Jun 30 (?) Confirmed Eruption VEI: 2
Episode 1 | Eruption | SW flank (1100 m) | |||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1961 Jun 30 (?) - Unknown | Evidence from Observations: Reported | |||||||||||||||||||||||||||||
List of 4 Events for Episode 1 at SW flank (1100 m)
|
1957 Jul 2 ± 182 days - 1960 Aug 10 (?) Confirmed Eruption VEI: 2
Episode 1 | Eruption | SW flank | ||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1957 Jul 2 ± 182 days - 1960 Aug 10 (?) | Evidence from Observations: Reported | ||||||||||||||||||||||||
List of 3 Events for Episode 1 at SW flank
|
1956 Sep 8 - 1956 Sep 9 Confirmed Eruption VEI: 2
Episode 1 | Eruption | 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
|
1953 Feb 15 - 1954 Oct 5 (?) Confirmed Eruption VEI: 3
Episode 1 | Eruption | 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)
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1950 Jul 2 - 1950 Aug 18 Confirmed Eruption VEI: 2 (?)
Episode 1 | Eruption | 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
|
1949 Jun Confirmed Eruption
Episode 1 | Eruption | ||||
---|---|---|---|---|
1949 Jun - Unknown | Evidence from Observations: Reported |
1913 Sep Confirmed Eruption VEI: 1
Episode 1 | Eruption | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1913 Sep - Unknown | Evidence from Observations: Reported | ||||||||||||||
List of 1 Events for Episode 1
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There is data available for 1 deformation periods. Expand each entry for additional details.
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.
There is no Emissions History data available for Trident.
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.
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 |
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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) | -- |
Alaska Volcano Observatory (Link to Trident) | The Alaska Volcano Observatory (AVO) is a joint program of the U.S. Geological Survey (USGS), the Geophysical Institute of the University of Alaska Fairbanks (UAFGI), and the State of Alaska Division of Geological and Geophysical Surveys (ADGGS). AVO was formed in 1988, and uses federal, state, and university resources to monitor and study Alaska's hazardous volcanoes, to predict and record eruptive activity, and to mitigate volcanic hazards to life and property. |
Copernicus Browser | The Copernicus Browser replaced the Sentinel Hub Playground browser in 2023, to provide access to Earth observation archives from the Copernicus Data Space Ecosystem, the main distribution platform for data from the EU Copernicus missions. |
MIROVA | Middle InfraRed Observation of Volcanic Activity (MIROVA) is a near real time volcanic hot-spot detection system based on the analysis of MODIS (Moderate Resolution Imaging Spectroradiometer) data. In particular, MIROVA uses the Middle InfraRed Radiation (MIR), measured over target volcanoes, in order to detect, locate and measure the heat radiation sourced from volcanic activity. |
MODVOLC Thermal Alerts | Using infrared satellite Moderate Resolution Imaging Spectroradiometer (MODIS) data, scientists at the Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, developed an automated system called MODVOLC to map thermal hot-spots in near real time. For each MODIS image, the algorithm automatically scans each 1 km pixel within it to check for high-temperature hot-spots. When one is found the date, time, location, and intensity are recorded. MODIS looks at every square km of the Earth every 48 hours, once during the day and once during the night, and the presence of two MODIS sensors in space allows at least four hot-spot observations every two days. Each day updated global maps are compiled to display the locations of all hot spots detected in the previous 24 hours. There is a drop-down list with volcano names which allow users to 'zoom-in' and examine the distribution of hot-spots at a variety of spatial scales. |
WOVOdat
Single Volcano View Temporal Evolution of Unrest Side by Side Volcanoes |
WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.
GVMID Data on Volcano Monitoring Infrastructure The Global Volcano Monitoring Infrastructure Database GVMID, is aimed at documenting and improving capabilities of volcano monitoring from the ground and space. GVMID should provide a snapshot and baseline view of the techniques and instrumentation that are in place at various volcanoes, which can be use by volcano observatories as reference to setup new monitoring system or improving networks at a specific volcano. These data will allow identification of what monitoring gaps exist, which can be then targeted by remote sensing infrastructure and future instrument deployments. |
Volcanic Hazard Maps | The IAVCEI Commission on Volcanic Hazards and Risk has a Volcanic Hazard Maps database designed to serve as a resource for hazard mappers (or other interested parties) to explore how common issues in hazard map development have been addressed at different volcanoes, in different countries, for different hazards, and for different intended audiences. In addition to the comprehensive, searchable Volcanic Hazard Maps Database, this website contains information about diversity of volcanic hazard maps, illustrated using examples from the database. This site is for educational purposes related to volcanic hazard maps. Hazard maps found on this website should not be used for emergency purposes. For the most recent, official hazard map for a particular volcano, please seek out the proper institutional authorities on the matter. |
IRIS seismic stations/networks | Incorporated Research Institutions for Seismology (IRIS) Data Services map showing the location of seismic stations from all available networks (permanent or temporary) within a radius of 0.18° (about 20 km at mid-latitudes) from the given location of Trident. Users can customize a variety of filters and options in the left panel. Note that if there are no stations are known the map will default to show the entire world with a "No data matched request" error notice. |
UNAVCO GPS/GNSS stations | Geodetic Data Services map from UNAVCO showing the location of GPS/GNSS stations from all available networks (permanent or temporary) within a radius of 20 km from the given location of Trident. Users can customize the data search based on station or network names, location, and time window. Requires Adobe Flash Player. |
DECADE Data | The DECADE portal, still in the developmental stage, serves as an example of the proposed interoperability between The Smithsonian Institution's Global Volcanism Program, the Mapping Gas Emissions (MaGa) Database, and the EarthChem Geochemical Portal. The Deep Earth Carbon Degassing (DECADE) initiative seeks to use new and established technologies to determine accurate global fluxes of volcanic CO2 to the atmosphere, but installing CO2 monitoring networks on 20 of the world's 150 most actively degassing volcanoes. The group uses related laboratory-based studies (direct gas sampling and analysis, melt inclusions) to provide new data for direct degassing of deep earth carbon to the atmosphere. |
Large Eruptions of Trident | Information about large Quaternary eruptions (VEI >= 4) is cataloged in the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database of the Volcano Global Risk Identification and Analysis Project (VOGRIPA). |
EarthChem | EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS). |