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Bogoslof Island

Bogoslof

Stratovolcano · United States · 150m

Bogoslof is the summit of a largely submarine volcano located in the Bering Sea, 50 km behind the main Aleutian arc. The island is about 1.5 x 0.6 km wide and due to its frequent eruptive activity and energetic wave action, has changed shape dramatically since it was first mapped in the late 1700s. The rounded lava dome and offshore spire at the northern tip of the island (bottom-center) formed in 1992. The circular, flat area at the right is a remnant of the 1927 lava dome, and the steep pinnacle is Castle Rock, a 1796 dome remnant.
Bogoslof is the summit of a largely submarine volcano located in the Bering Sea, 50 km behind the main Aleutian arc. The island is about 1.5 x 0.6 km wide and due to its frequent eruptive activity and energetic wave action, has changed shape dramatically since it was first mapped in the late 1700s. The rounded lava dome and offshore spire at the northern tip of the island (bottom-center) formed in 1992. The circular, flat area at the right is a remnant of the 1927 lava dome, and the steep pinnacle is Castle Rock, a 1796 dome remnant. · Photo: Photo by Terry Keith, 1994 (Alaska Volcano Observatory, U.S. Geological Survey). · Wikimedia Commons
Type
Stratovolcano
Country
United States
Region
North America Volcanic Regions / Aleutian Ridge Volcanic Arc
Elevation
150m
Coordinates
53.930, -168.030
Last eruption
2017
Tectonic setting
Subduction zone / Intermediate crust (15-25 km)
Landform
Composite
Major rock type
Trachyandesite / Basaltic Trachyandesite
Geological summary

Bogoslof is the emergent summit of a submarine volcano that lies 40 km N of the main Aleutian arc. It rises 1,500 m above the Bering Sea floor. Repeated construction and destruction of lava domes at different locations during historical time has greatly modified the appearance of this "Jack-in-the-Box" volcano and has introduced a confusing nomenclature applied during frequent visits by exploring expeditions. The present triangular-shaped, 0.75 x 2 km island consists of remnants of lava domes emplaced from 1796 to 1992. Castle Rock (Old Bogoslof) is a steep-sided pinnacle that is a remnant of a spine from the 1796 eruption. The small Fire Island (New Bogoslof), about 600 m NW of Bogoslof Island, is a remnant of a lava dome formed in 1883.

From Wikipedia

Bogoslof Island or Agasagook Island is the summit of a submarine stratovolcano at the south edge of the Bering Sea, 35 miles (56 km) northwest of Unalaska Island of the Aleutian Islands chain. It has a land area of 319.3 acres (1.292 km2) and is uninhabited. It is 1,040 meters (3,410 ft) long and 1,512 m (4,961 ft) wide, with a peak elevation of 490 feet (150 m). The stratovolcano rises about 6,000 ft (1,800 m) from the seabed, but the summit is the only part that projects above sea level. The island is believed to be relatively new, with the volcano being entirely below sea level before 1796, and most of the presently 300-acre island being formed by eruptions since 1900.

Wikipedia · CC BY-SA · Read full article →

Eruption history

Summary (VEI over time)
Click a bar to see individual eruptions
1796~1818 · 2 eruptions · max VEI 31862~1884 · 1 eruptions · max VEI 31906~1928 · 5 eruptions · max VEI 31928~1950 · 1 eruptions · max VEI 11950~1972 · 1 eruptions · max VEI 01972~1994 · 1 eruptions · max VEI 31994~2016 · 1 eruptions · max VEI 317961840190619501994

Detailed timeline

  1. 2016VEI 3Observed
    2016-12-20 – 2017-08-30
    Central vent, just below sea level
  2. 1992VEI 3Observed
    1992-07-06 – 1992-07-24
    North tip of island (NE of 1927 dome)
  3. 1951VEI 0Geological estimate
    1951-09-21 – Ongoing
  4. 1931VEI 1Observed
    1931-10-31 – Ongoing
    1926-1927 dome
  5. 1926VEI 2Observed
    1926-07 – 1928
    Between New and Old Bogoslof
  6. 1913VEI ?Geological estimate
    1913-07 – Ongoing
    Tahoma Peak
  7. 1909VEI 2Observed
    1909-09 – 1910-09-19
    Tahoma Peak
  8. 1908VEI ?Geological estimate
    1908-01-15 – Ongoing
    Metcalf Peak
  9. 1906VEI 3Observed
    1906-03-01 – 1907-09-01
    Metcalf Peak, McCullough Peak
  10. 1883VEI 3Observed
    1883-09-27 – 1895
    New Bogoslof (Grewingk)
  11. 1806VEI 2Observed
    1806 – 1823
    Old Bogoslof (Castle Rock)
  12. 1796VEI 3Observed
    1796-05 – 1804
    Old Bogoslof (Castle Rock)

External links

⚠ For reference only. Not for emergency response.