USFWS
Alaska Maritime National Wildlife Refuge
Alaska Region

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Wildlife

Ring of Fire
Watching an Island Grow

Dynamic Bogoslof Island

Since the late 1700s an island cluster north of the main arc of the Aleutian Islands has explosively grown, disappeared, reappeared, and changed shapes. As recently as 1992 steam and ash plumes rose several miles above Bogoslof Island. A new lava dome, about 150 m high, appeared on the north tip of the island near the remnant of a dome created in 1927.

Volcanic Home for Marine Animals

The islands are the emergent tips of an active submarine volcano rising more than 4,500 feet (1,500 m) from the floor of the Bering Sea. They are home to marine birds and mammals and part of the Alaska Maritime National Wildlife Refuge.

TRACING BOGOSLOF'S VOLCANIC ACTIVITY

First Reports

In 1768 Russian sailors reported a small, rocky prominence - called Ship Rock - was present in the area where Bogoslof and Fire islands now rise. An explosive eruption began in 1796.

EYE WITNESS ACCOUNT - Thunder and earthquakes rock the islands of Umnak and Unalaska in the eastern Aleutian Islands. A glowing ash cloud obscures the horizon toward an important fur seal and sea lion hunting island. When the cloud clears, local Natives and Russian-American Company personnel see a huge island "shaped like a black pointed cap." Twice the volcano hurls rocks as far as Umnak – 30 miles. The island continues to grow. In 1804 when sea lion hunters visit Agashagok (Aleut/Unangan) or Bogoslof Island, they find the water warm and the ground still too hot for walking.

Changing Island Profile

1768 Ship Rock present in general area.
1796 Eruptions begin building a second island, south of Ship Rock
1804 Island formed; called Bogoslof / Old Bogoslof /or Castle Rock
1823 Bogoslof stops increasing in size
1882 Fire Island rises steaming, north of Ship Rock
1890 Ship Rock has fallen
1906-10 Several eruptions form and destroy new peaks
1922 Only Fire Island and Bogoslof remain, separated by open water
1926-27 Kenyon Dome forms, surrounded by a warm saltwater lagoon
Fire Island and Bogoslof are joined as one island again
1935 Open water separates Bogoslof and Fire islands again
1947 Size of Fire and Bogoslof islands greatly reduced since 1935
1953 Bogoslof further reduced by about 25% since 1947
Saltwater lagoon now small pond
1973 Bogoslof reduced by about 30% since 1953
Saltwater pond gone
1992 steam and ash rise above island, new lava dome formed

LINKS to learn more

Bogoslof in the Volcano Atlas

Wildlife responds to changes on Bogoslof Island

Last updated:September 8, 2008