World Library  
Flag as Inappropriate
Email this Article

Bobrof Island

Nautical Chart of Bobrof Island
Bobrof Island is located in Alaska
Location in Alaska
Bobrof Volcano
Bobrof Island and the volcano
Elevation 2,421 ft (738 m)[1]
Bobrof Volcano is located in Alaska
Bobrof Volcano
Location North Pacific, part of Alaska
Range Aleutian Islands
Coordinates [2]
Type Stratovolcano
Age of rock Holocene
Volcanic arc/belt Aleutian Islands

Bobrof Island (Aleut: Walĝa[3]) is one of the Andreanof Islands subgroup of the Aleutian Islands in southwestern Alaska, US.[4] Bobrof Island is a small, uninhabited island about 9 miles (14 km) north and west of Kanaga Island, and 7 miles (11 km) northeast of Cape Sudak on Tanaga Island. Bobrof Island is 2.6 miles (4.2 km) long and 1.8 miles (2.9 km) wide with an area of 3 square miles (7.8 km2), and consists primarily of the 2,421-foot (738 m) high Bobrof Volcano.[4] The volcanic crater, or cone, has been heavily dissected.[5] Underwater deposits adjacent to the island's northeast flank suggest an immense debris-avalanche has taken place.[4]


  • Bobrof Volcano 1
    • Geography and geology 1.1
  • References 2
  • External links 3

Bobrof Volcano

Bobrof Volcano is an inactive stratovolcano which forms the small Bobrof Island. No recorded eruptions have taken place at Bobrof or in its vicinity. It has been considered as Holocene age.

Geography and geology

Because of the inclusion of Alaska, the United States has the largest number of active volcanoes in the world, many of them geologically young.[6] In Alaska, at least 50 volcanoes, including those in the Aleutian archipelago, have erupted in historical time.[7] Alaska accounts for about 80% of the United States' volcanoes, excluding the seamounts in the area, about 8% of the world's volcanoes, and most of these are located among the Aleutian Islands.[7] The Aleutian Islands arc forms the northern boundary of the Pacific Ring of Fire,[7] where tectonic activity generates earthquakes and volcanic eruptions regularly.

The volcano is thought to be of Holocene age.[4] Though no historical eruptions have taken place at Bobrof, it has erupted at least once. This data can be confirmed through pyroclastic flow deposits containing andesite.[4] Once these flows were studied, at a building intended for earthquake monitoring, they confirmed that Bobrof was prone to explosive activity.[8] There are lava deposits on the mountain which also suggest activity similar to shield eruptions.[8] In collected samples, there are traces of basaltic andesite and dacite.[9] No complete publications exist for Bobrof's definite geology, just those with facts and some information.[9]


  • Bobrof Island: Block 1132, Census Tract 1, Aleutians West Census Area, Alaska United States Census Bureau
  1. ^ "Bobrof Volcano, Alaska". Retrieved 2011-08-08. 
  2. ^ "Bobrof Volcano".  
  3. ^  
  4. ^ a b c d e "Bobrof".  
  5. ^  
  6. ^ Ewert, John; Guffanti, Marianne; Cervelli, Peter; Quick, James (2006). "The National Volcano Early Warning System (NVEWS): U.S. Geological Survey Fact Sheet FS 2006-3142".  
  7. ^ a b c "Alaska GeoSurvey News: NL 2008-1" 11 (1). Alaska Division of Geological & Geophysical Surveys. March 2008. pp. 1–14. Retrieved July 9, 2009. 
  8. ^ a b "Bobrof description and statistics".  
  9. ^ a b Myers, J. D. (1994). "The geology, geochemistry and petrology of the recent magmatic phase of the central and western Aleutian Arc" (PDF).  

External links

  • Bobrof Island Photos Photographs from Bobrof Island, July 2008
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Hawaii eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.