Photo of this volcano
Google Earth icon
  Google Earth Placemark with Features
  • United States
  • Alaska
  • Stratovolcano(es)
  • 2220 BCE
  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 57.05°N
  • 135.75°W

  • 970 m
    3182 ft

  • 315040
  • Latitude
  • Longitude

  • Summit

  • Volcano

The Global Volcanism Program has no activity reports for Edgecumbe.

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

The Global Volcanism Program has no Bulletin Reports available for Edgecumbe.

Basic Data

Volcano Number

Last Known Eruption



2220 BCE

970 m / 3182 ft


Volcano Types

Pyroclastic cone(s)
Lava dome(s)

Rock Types

Andesite / Basaltic Andesite
Basalt / Picro-Basalt

Tectonic Setting

Continental crust (> 25 km)


Within 5 km
Within 10 km
Within 30 km
Within 100 km

Geological Summary

The Pleistocene-to-Holocene Mount Edgecumbe volcanic field covers about 260 sq km of Kruzov Island west of Sitka in the SE panhandle of Alaska. The basaltic-to-dacitic field is dominated by the large composite cones of Mount Edgecumbe, Crater Ridge, and Shell Mountain and has an unusual tectonic setting only 16 km east of the Queen Charlotte-Fairweather transform fault separating the North American and Pacific plates. Mount Edgecumbe, a 970-m-high stratovolcano with a well-defined crater, is the largest volcano of the Edgecumbe field. Crater Ridge is truncated by a 1.6-km-wide, 240-m-deep caldera. These and other vents of the volcanic field are oriented along a SW-NE line. Volcanic activity originated about 600,000 years ago along fissures cutting Kruzof Island. A series of major silicic explosive eruptions took place about 9000-13,000 radiocarbon years ago. The latest dated eruptions were phreatomagmatic explosions during the mid-Holocene, and all postglacial activity has been pyroclastic. Reports of historical eruptions of Mount Edgecumbe are unsubstantiated.


The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography.

Beget J E, Motyka R J, 1998. New dates on late Pleistocene dacitic tephra from the Mount Edgecumbe volcanic field, southeastern Alaska. Quat Res, 49: 123-125.

Brew D A, Muffler L J P, Loney R A, 1969. Reconnaissance geology of the Mount Edgecumbe volcanic field, Kruzof Island, southeastern Alaska. U S Geol Surv Prof Pap, 650-D: 1-18.

Henning R A, Rosenthal C H, Olds B, Reading E (eds), 1976. Alaska's volcanoes, northern link in the ring of fire. Alaska Geog, 4: 1-88.

IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth's Interior..

Riehle J R, 1996. The Mount Edgecumbe volcanic field: a geologic history. U S Dept Agriculture, 42 p.

Riehle J R, Brew D A, Lanphere M A, 1989. Geologic map of the Mount Edgecumbe volcanic field, Kruzof Island, southeastern Alaska. U S Geol Surv Map, I-1983.

Riehle J R, Champion D E, Brew D A, Lanphere M A, 1992. Pyroclastic deposits of the Mount Edgecumbe volcanic field, southeast Alaska: eruptions of a stratified magma chamber. J Volc Geotherm Res, 53: 117-143.

Riehle J R, Mann D H, Peteet D M, Engstrom D R, Brew D A, Meyer C E, 1992. The Mount Edgecumbe tephra deposits, a marker horizon in southeastern Alaska near the Pleistocene-Holocene boundary. Quat Res, 37: 183-202.

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.

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

Eruptive History

Summary of Holocene eruption dates and Volcanic Explosivity Indices (VEI).

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
2220 BCE ± 100 years Unknown Confirmed   Radiocarbon (uncorrected)
3810 BCE ± 75 years Unknown Confirmed   Radiocarbon (uncorrected)
7220 BCE ± 150 years Unknown Confirmed   Radiocarbon (uncorrected)

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.


Gora Edgkom | St. Hyacinthe, Mount | Saint Hyacinthe, Mount


Feature Name Feature Type Elevation Latitude Longitude
Shell Mountain Stratovolcano 490 m 57° 7' 34" N 135° 40' 59" W


Feature Name Feature Type Elevation Latitude Longitude
Crater Ridge Dome 732 m 57° 4' 52" N 135° 42' 25" W

Photo Gallery

The Pleistocene-to-Holocene Mount Edgecumbe volcanic field covers about 260 sq km of Kruzov Island west of Sitka in the SE panhandle of Alaska. This aerial view shows colorful slopes of oxidized scoria on Crater Ridge in the foreground, with an unnamed crater in the background. Crater Ridge is truncated by a 1.6-km-wide, 240-m deep caldera. The youngest eruptions from Mount Edgecumbe are about 4000 years old. Mount Edgecumbe itself, a 967-m-high stratovolcano with a well-defined crater, is the largest volcano of the Edgecumbe field.

Photo by Jim Riehle (U.S. Geological Survey, Alaska Volcano Observatory).

Smithsonian Sample Collections Database

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

Affiliated Sites

Large Eruptions of Edgecumbe 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).
WOVOdat 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.
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).
MODVOLC - HIGP MODIS Thermal Alert System 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.
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.