Ofu-Olosega
Ofu-Olosega from Space Shuttle.
Elevation	639 m (2,096 feet)
Location	American Samoa
Prominence	639 m
Coordinates	14.175° S 169.618° W
Topo map	USGS
Type	Shield volcanoes
Last eruption	1866

Ofu and Olosega are parts of a volcanic doublet in the Manu‘a Group of the Samoa Archipelago—part of American Samoa. In topography a summit is a point on a surface which is higher in Elevation than all points immediately adjacent to American Samoa (Amerika Sāmoa or sm ''Sāmoa Amelika'' is an unincorporated territory of the United States located in the South Pacific Ocean, southeast A geographic coordinate system enables every location on the Earth to be specified in three coordinates using mainly a spherical coordinate system. A topographic map is a type of Map characterized by large-scale detail and quantitative representation of relief, usually using Contour lines in modern The United States Geological Survey ( USGS) is a scientific agency of the United States government. Mountains can be characterized in several ways Some mountains are Volcanoes and can be characterized by the type of lava and eruptive history A shield volcano is a large Volcano with shallow-sloping sides Plate tectonics and hotspots Divergent plate boundaries At the Year 1866 ( MDCCCLXVI) was a Common year starting on Monday (link will display the full calendar of the Gregorian calendar (or a Common Manua or the Manua Islands Group (Samoan Manua tele) consists of three main islands Ta{{okina}}u, Ofu and Olosega. American Samoa (Amerika Sāmoa or sm ''Sāmoa Amelika'' is an unincorporated territory of the United States located in the South Pacific Ocean, southeast Although geographically separate volcanic remnants, only a narrow strait (Asaga) naturally bridged by a shallow coral reef separates them. A strait is a narrow navigable Channel of water that connects two larger navigable bodies of water Coral reefs are Aragonite structures produced by living organisms found in marine waters with little to no nutrients in the water Before 1970, one had to wade between the two islands at low tide; now a road bridge over the straight connects villages on Ofu with those on Olosega.

Ofu

Ofu is the western part of the volcanic outcrop of Ofu-Olosega Island. The main village of Ofu is located on the western shore, protected behind an offshore islet (eroded tuff cone) known as Nu‘utele. Ofu may refer to Ofu (Tonga, an island and its village in Vava'u in Tonga Ofu-Olosega, an island in the Manu'a group in American Phreatomagmatic eruptions are defined as juvenile forming eruptions as a result of interaction between water and Magma. Ofu has a small airport and a boat harbor that serve the population on Ofu and Olosega.

South shore of Ofu seen from Olosega across the narrow straight that separates them. The sharp peak, an eroding dike complex, is named Sunu‘itao.

Most of the southern shore and associated coral reef are part of the National Park of American Samoa. The National Park of American Samoa is a national park on the American territory of American Samoa, distributed across three separate islands Tutuila, The U. S. National Park Service is presently (2005) negotiating with village councils on Olosega to expand the park around that island. The National Park Service ( NPS) is the United States federal agency that manages all National Parks, many National Monuments, and other conservation

The island forms the Ofu County subdivision of the Manua District. Manua or the Manua Islands Group (Samoan Manua tele) consists of three main islands Ta{{okina}}u, Ofu and Olosega. It has a land area of 7. 215 km² (2. 786 sq mi), and had an official population of 289 persons as of the 2000 census.

Olosega

Olosega Island is a remnant of the Sili shield volcano, the caldera of which may lie submerged off the north shore. A shield volcano is a large Volcano with shallow-sloping sides A caldera is a cauldron-like volcanic feature formed by the collapse of land following a volcanic eruption The undersea eruption of 1866 was actually 3 km east of Olosega, on a submarine ridge that extends eastsoutheast to nearby Ta‘ū. Ta‘ū is the largest island in the Manu‘a Group and the easternmost volcanic island of the Samoan Islands

The island forms the Olosega County subdivision of the Manua District. Manua or the Manua Islands Group (Samoan Manua tele) consists of three main islands Ta{{okina}}u, Ofu and Olosega. It has a land area of 5. 163 km² (1. 993 sq mi), and had an official population of 216 persons as of the 2000 census.

There are two villages on Olosega: Olosega and Sili. Sili now consists of but one standing residence after much of the village was destroyed by hurricanes (and subsequently abandoned). Nearly all of the population of Olosega now resides in Olosega village along the southwestern-facing shore.

References

• Office of the Governor. 2004. Manu‘a ma Amerika. A brief historical documentary. Manu‘a Centennial. 16 July 1904. 16 July 2004. Office of the Governor, American Samoa Government. 20 p.
• Smithsonian Institution Global Volcanism Program: Ofu-Olosega
• Ofu County and Olosega County, Manu'a District, United States Census Bureau

External links

• National Park Service map of the Manu‘a Islands
• Persistence of Coral Reefs Under Extreme Environmental Stress in American Samoa G. Piniak, C. Birkeland, and G. Garrison (2004). University of Hawaii.