Semisopochnoi Island or Unyak Island (obsolete Russian: Семисопочной, modern Russian: Семисопочный Semisopochny – "having seven hills"; Aleut: Unyax̂[1]) is part of the Rat Islands group in the western Aleutian Islands of Alaska. The island is uninhabited and provides an important nesting area for maritime birds. The island is of volcanic origin, containing several volcanoes including Mount Young. It has a land area of 85.558 square miles (221.59 square km), measuring 11 miles (18 km) in length and 12 miles (20 km) in width.
Semisopochnoi
Eastern cone of Mount Young in the Semisopochnoi Caldera.
Top: Location of Semisopochnoi in the Aleutians. Amchixtam Chaxsxii, just southeast of Semisopochnoi, is an underwater volcano. Bottom: Location of Semisopochnoi in Alaska
At 179°46' East (+179.7667) (in the Eastern Hemisphere), the easternmost tip of Semisopochnoi is, by longitude, the easternmost land location in the United States and North America. Semisopochnoi sits only 14 minutes (0.2333 degrees) or 9.7 miles (15.6 km) west of the 180th meridian.
The large least and crested auklet colony near Sugarloaf Head is one of the largest among the nine auklet colonies in the Aleutian Islands. Crested auklets and least auklets breed in one colony, located on the south facing slopes of Sugarloaf Peak volcano and its associated cinder cones near Sugarloaf Head. Semisopochnoi Island also supports a significant population of red-faced cormorants.
In total, Semisopochnoi supports well over a million seabirds, most of which are least auklets or crested auklets.[2]
Geology
Satellite photo showing the Seven Mountains of Semisopochnoi
Semisopochnoi, the largest subaerialvolcano of the western Aleutians, is 20 km wide at sea level and contains a caldera 8 km wide that formed as a result of the collapse of a low-angle, dominantly basaltic volcano following the eruption of a large volume of daciticpumice. The high point of the island is 1,221 meter Anvil Peak, a double-peaked cone that forms much of the island's northern part. The three-peaked, 774-meter high Mount Young (formerly named Mount Cerberus) is a volcano within the caldera. Each of the peaks contains a summit crater; lava flows on the northern flank of Mt. Young appear more recent than those on the southern side. Other post-caldera volcanoes include the symmetrical 855 m high Sugarloaf Peak south-southeast of the caldera and Lakeshore Cone, a small cinder cone at the edge of Fenner Lake in the northeast part of the caldera. Most documented historical eruptions have originated from Mt. Young, although Coats (1950) considered that both Sugarloaf and Lakeshore Cone within the caldera could have been active during historical time.[3][4][5]
Semisopochnoi's last known volcanic eruptions took place in October 2018 and July 2019.[6] A historic eruption of Semisopochnoi was reported in 1873, and at least four others may have occurred in the previous hundred years, but documentation is scant. These eruptions apparently emanated from the flanks of Mount Young; the most recent flow appears to be less than a century old.[7]
Easternmost North America location debate
Semisopochnoi nautical chart
Semisopochnoi's position in the Aleutian Island Chain gives it the distinction of being the Aleutian island most immediately West of the 180th meridian, giving it longitudinal coordinates in the Eastern Hemisphere. Therefore, some have argued it is technically the easternmost location in North America. This is a counterintuitive argument considering its location near the extreme Western boundary of the United States and depends on a series of assumptions about the definition of boundaries between hemispheres, boundaries between continents, as well as whether island locations should even be considered part of a continent.
The other contenders for the title of easternmost North American location are Nordost Rundingen, Greenland at 12°08' West (-12.1333) and Cape Spear, Newfoundland, Canada at 52°37' West (-52.6167) —which, along with Semisopochnoi, are all island locations. Cape St. Charles at 55° 37' West (-55.6167) on the Labrador Peninsula is the easternmost point of mainland North America. Cape Spear is the easternmost location relative to the geographic center of North America if Greenland is excluded because it is not politically part of North America. For this and other reasons, Cape Spear is traditionally considered to be the easternmost location in North America.
Renaming of Mount Cereberus
On December 12, 2022, a Congressional bill authored by Senator Lisa Murkowski was passed by the 117th Congress renaming Mount Cerberus "Mount Young" in honor of long-serving Alaska U.S. Representative Don Young, who died on March 18, 2022.[8][9]
References
^Bergsland, K. (1994). Aleut Dictionary. Fairbanks: Alaska Native Language Center.
^Wood, C. A., and Kienle, Juergen, (eds.), 1990, Volcanoes of North America: United States and Canada: New York, Cambridge University Press, 354 p.
^Ruskin, Liz (2022-12-28). "Mount Young: Aleutian volcano renamed for explosive Alaska congressman". Alaska Public Media. Retrieved 2022-12-30.
^Murkowski, Lisa. "S.5066 — 117th Congress (2021-2022)". Congress.gov. Retrieved 2022-12-28.
External links
Semisopochnoi Photos Photographs from Semisopochnoi Island, July 2008
Google Earth view
May 11, 2023
semisopochnoi, island, unyak, island, obsolete, russian, Семисопочной, modern, russian, Семисопочный, semisopochny, having, seven, hills, aleut, unyax, part, islands, group, western, aleutian, islands, alaska, island, uninhabited, provides, important, nesting,. Semisopochnoi Island or Unyak Island obsolete Russian Semisopochnoj modern Russian Semisopochnyj Semisopochny having seven hills Aleut Unyax 1 is part of the Rat Islands group in the western Aleutian Islands of Alaska The island is uninhabited and provides an important nesting area for maritime birds The island is of volcanic origin containing several volcanoes including Mount Young It has a land area of 85 558 square miles 221 59 square km measuring 11 miles 18 km in length and 12 miles 20 km in width SemisopochnoiEastern cone of Mount Young in the Semisopochnoi Caldera Top Location of Semisopochnoi in the Aleutians Amchixtam Chaxsxii just southeast of Semisopochnoi is an underwater volcano Bottom Location of Semisopochnoi in AlaskaSemisopochnoiLocation on a map of AlaskaGeographyLocationBering SeaCoordinates51 57 05 N 179 36 03 E 51 95139 N 179 60083 E 51 95139 179 60083 Coordinates 51 57 05 N 179 36 03 E 51 95139 N 179 60083 E 51 95139 179 60083ArchipelagoRat IslandsArea221 59 km2 85 56 sq mi Length18 km 11 2 mi Width20 km 12 mi Highest elevation1 221 m 4006 ft Administration United StatesState AlaskaAt 179 46 East 179 7667 in the Eastern Hemisphere the easternmost tip of Semisopochnoi is by longitude the easternmost land location in the United States and North America Semisopochnoi sits only 14 minutes 0 2333 degrees or 9 7 miles 15 6 km west of the 180th meridian Contents 1 Wildlife 2 Geology 3 Easternmost North America location debate 4 Renaming of Mount Cereberus 5 References 6 External linksWildlife EditSemisopochnoi has no native land mammals Arctic foxes were introduced to the island during the 19th century for fur farming and removed in 1997 Most ground nesting bird species Aleutian cackling goose rock ptarmigan and most burrow nesting seabirds storm petrels ancient murrelets Cassin s auklets tufted puffins were extirpated by foxes Semisopochnoi Island is currently in the early stages of recovery The island has remained free of Norway rats The large least and crested auklet colony near Sugarloaf Head is one of the largest among the nine auklet colonies in the Aleutian Islands Crested auklets and least auklets breed in one colony located on the south facing slopes of Sugarloaf Peak volcano and its associated cinder cones near Sugarloaf Head Semisopochnoi Island also supports a significant population of red faced cormorants In total Semisopochnoi supports well over a million seabirds most of which are least auklets or crested auklets 2 Geology Edit Satellite photo showing the Seven Mountains of Semisopochnoi Semisopochnoi the largest subaerial volcano of the western Aleutians is 20 km wide at sea level and contains a caldera 8 km wide that formed as a result of the collapse of a low angle dominantly basaltic volcano following the eruption of a large volume of dacitic pumice The high point of the island is 1 221 meter Anvil Peak a double peaked cone that forms much of the island s northern part The three peaked 774 meter high Mount Young formerly named Mount Cerberus is a volcano within the caldera Each of the peaks contains a summit crater lava flows on the northern flank of Mt Young appear more recent than those on the southern side Other post caldera volcanoes include the symmetrical 855 m high Sugarloaf Peak south southeast of the caldera and Lakeshore Cone a small cinder cone at the edge of Fenner Lake in the northeast part of the caldera Most documented historical eruptions have originated from Mt Young although Coats 1950 considered that both Sugarloaf and Lakeshore Cone within the caldera could have been active during historical time 3 4 5 Semisopochnoi s last known volcanic eruptions took place in October 2018 and July 2019 6 A historic eruption of Semisopochnoi was reported in 1873 and at least four others may have occurred in the previous hundred years but documentation is scant These eruptions apparently emanated from the flanks of Mount Young the most recent flow appears to be less than a century old 7 Easternmost North America location debate Edit Semisopochnoi nautical chart Semisopochnoi s position in the Aleutian Island Chain gives it the distinction of being the Aleutian island most immediately West of the 180th meridian giving it longitudinal coordinates in the Eastern Hemisphere Therefore some have argued it is technically the easternmost location in North America This is a counterintuitive argument considering its location near the extreme Western boundary of the United States and depends on a series of assumptions about the definition of boundaries between hemispheres boundaries between continents as well as whether island locations should even be considered part of a continent The other contenders for the title of easternmost North American location are Nordost Rundingen Greenland at 12 08 West 12 1333 and Cape Spear Newfoundland Canada at 52 37 West 52 6167 which along with Semisopochnoi are all island locations Cape St Charles at 55 37 West 55 6167 on the Labrador Peninsula is the easternmost point of mainland North America Cape Spear is the easternmost location relative to the geographic center of North America if Greenland is excluded because it is not politically part of North America For this and other reasons Cape Spear is traditionally considered to be the easternmost location in North America Renaming of Mount Cereberus EditOn December 12 2022 a Congressional bill authored by Senator Lisa Murkowski was passed by the 117th Congress renaming Mount Cerberus Mount Young in honor of long serving Alaska U S Representative Don Young who died on March 18 2022 8 9 References Edit Bergsland K 1994 Aleut Dictionary Fairbanks Alaska Native Language Center Audubon Site Profile Semisopochnoi Island Semisopochnoi Global Volcanism Program Smithsonian Institution Retrieved 2021 06 28 Coats R R 1950 Volcanic activity in the Aleutian Arc U S Geol Surv Bull 974 B 35 47 Alaska Volcano Observatory Semisopochnoi Semisopochnoi Historic eruptions Wood C A and Kienle Juergen eds 1990 Volcanoes of North America United States and Canada New York Cambridge University Press 354 p Ruskin Liz 2022 12 28 Mount Young Aleutian volcano renamed for explosive Alaska congressman Alaska Public Media Retrieved 2022 12 30 Murkowski Lisa S 5066 117th Congress 2021 2022 Congress gov Retrieved 2022 12 28 External links EditSemisopochnoi Photos Photographs from Semisopochnoi Island July 2008 Google Earth view Retrieved from https en wikipedia org w index php title Semisopochnoi Island amp oldid 1146598189, wikipedia, wiki, book, books, library,
