Ofu and Olosega are parts of a volcanic doublet in the

Manuʻa Islands The Manua Islands, or the Manua tele (Samoan: ''Manua tele''), in the Samoan Islands, consists of three main islands: Taū, Ofu and Olosega. The latter two are separated only by the shallow, 137-meter-wide Āsaga Strait, and are now connected b ...

, which is a part of

American Samoa American Samoa ( sm, Amerika Sāmoa, ; also ' or ') is an unincorporated territory of the United States located in the South Pacific Ocean, southeast of the island country of Samoa. Its location is centered on . It is east of the International ...

in the

Samoan Islands The Samoan Islands ( sm, Motu o Sāmoa) are an archipelago covering in the central South Pacific, forming part of Polynesia and of the wider region of Oceania. Administratively, the archipelago comprises all of the Independent State of Samoa a ...

. These twin islands, formed from

shield volcano A shield volcano is a type of volcano named for its low profile, resembling a warrior's shield lying on the ground. It is formed by the eruption of highly fluid (low viscosity) lava, which travels farther and forms thinner flows than the more v ...

es, have a combined length of 6 km and a combined area of . Together, they have a population of about 500 people. Geographically, the islands are volcanic remnants separated by the narrow, ) Āsaga Strait, composed of shallow-water

coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups. Co ...

. Before 1970, people crossed between the two islands by waiting until low tide and then wading across the shallow water of the strait. Since 1970, there has been a bridge over the strait, providing a single-lane road that connects the two islands. The highest peak on Ofu Island is Mount Tumutumu (also called Tumu), at . The highest peak on Olosega is Mount Piumafua, at . The most recent volcanic eruption was in 1866, southeast of Olosega. Pre-historic artifacts discovered on Ofu by

archaeological Archaeology or archeology is the scientific study of human activity through the recovery and analysis of material culture. The archaeological record consists of artifacts, architecture, biofacts or ecofacts, sites, and cultural landscap ...

field work in the 1980s significantly furthered understanding of the ancient history of Ofu in particular, and the

Samoa Islands The Samoan Islands ( sm, Motu o Sāmoa) are an archipelago covering in the central South Pacific, forming part of Polynesia and of the wider region of Oceania. Administratively, the archipelago comprises all of the Independent State of Samoa a ...

and

Polynesia Polynesia () "many" and νῆσος () "island"), to, Polinisia; mi, Porinihia; haw, Polenekia; fj, Polinisia; sm, Polenisia; rar, Porinetia; ty, Pōrīnetia; tvl, Polenisia; tkl, Polenihia (, ) is a subregion of Oceania, made up of ...

in general. The artifacts include

ceramics A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelain ...

adze An adze (; alternative spelling: adz) is an ancient and versatile cutting tool similar to an axe but with the cutting edge perpendicular to the handle rather than parallel. Adzes have been used since the Stone Age. They are used for smoothing ...

s, and worked shell and bone pieces. Samples of red-slipped plainware ceramics were found that appear to have been crafted in the tradition of the Lapita culture. The field work, carried out by a team that included Pacific archaeology specialist

Patrick Vinton Kirch Patrick Vinton Kirch is an American archaeologist and Professor EmeritusPatrick V. Kirch
University ...

, focused on a site called To'aga ''(site AS-13-1)'', a coastal stretch on the south coast of Ofu. Dating of the artifacts suggested that Ofu has been continuously inhabited by humans for about 3,000 years.

Ofu

Ofu is the western part of the volcanic outcrop of Ofu-Olosega Island and the westernmost of the Manu'a Islands.Hills, J.W. (2010). ''O upu muamua i le Tala i le Lalolagi mo e ua faatoa a'oa'oina u lea mataupu: Elementary Geography''. Nabu Press. Page 63. . The main village of Ofu is located on the western shore, protected behind an offshore islet (eroded

tuff cone Volcanic cones are among the simplest volcanic landforms. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and s ...

) known as Nu'utele. Ofu has a small airport and a boat harbor that serve the population on Ofu and Olosega. The twice-weekly flight from

Pago Pago Pago Pago ( ; Samoan: )Harris, Ann G. and Esther Tuttle (2004). ''Geology of National Parks''. Kendall Hunt. Page 604. . is the territorial capital of American Samoa. It is in Maoputasi County on Tutuila, which is American Samoa's main island. ...

takes about half an hour, but the airport has been closed since April 2021 for runway rehabilitation leaving the island without air service. Olosega Native village 1896

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 in the United States territory of American Samoa, distributed across three islands: Tutuila, Ofu, and Ta‘ū. The park preserves and protects coral reefs, tropical rainforests, fruit bats, ...

. The island forms the

Ofu County Ofu County is a county in the Manu'a District in American Samoa American Samoa ( sm, Amerika Sāmoa, ; also ' or ') is an unincorporated territory of the United States located in the South Pacific Ocean, southeast of the island country of ...

subdivision of the

Manuʻa District The Manua District is one of the three primary administrative divisions of American Samoa. The district comprises the Manua Islands, which are located approximately 61 miles east of the main island, Tutuila. The Manua District is considered to ...

. It has a land area of 7.215 km² (2.786 sq mi), and had an official population of 176 persons as of the 2010 census. Situated on the south coast of the island is To'aga lagoon which has a high diversity of corals and fishes. The marine site has been part of long term research and study on coral reefs and global climate change. The island is also home to the

Samoa Flying-fox The Samoa flying fox or Samoan flying fox (''Pteropus samoensis'') is a species of flying fox in the family Pteropodidae. It is found in American Samoa, Fiji, and Samoa (where it is known as ''pe'a'' and ''pe'a vao''). Its natural habitat is subt ...

(''Pteropus samoensis''), a species of bat threatened by habitat loss.

Olosega

Olosega is the smallest island in the

. It is possible to walk across to Ofu Island at low tide. The name derives from Samoan ''ʻOlosega'', "fortress of

parakeet A parakeet is any one of many small to medium-sized species of parrot, in multiple genera, that generally has long tail feathers. Etymology and naming The name ''parakeet'' is derived from the French wor''perroquet'' which is reflected in ...

s." Olosega Island is a remnant of the Sili

, the

caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is ...

of which may lie submerged off the north shore. The volcanic eruption of 1866 was actually east of Olosega, on a

mid-ocean ridge A mid-ocean ridge (MOR) is a seafloor mountain system formed by plate tectonics. It typically has a depth of about and rises about above the deepest portion of an ocean basin. This feature is where seafloor spreading takes place along a diverge ...

that extends east southeast to nearby

Taʻū Taʻū is the largest island in the Manuʻa Islands and the easternmost volcanic island of the Samoan Islands. Taū is part of American Samoa. In the early 19th century, the island was sometimes called ''Opoun''. Taū is well known as the site ...

. The island forms the

Olosega County Olosega County is a county in the Manu'a District in American Samoa. It was the result of the subdivision of the prior Luanuu County in two, with the other newly created county being Ofu, first reported on the 1930 U.S. Census. It contains the two ...

subdivision of the

. It has a land area of 5.163 km² (1.993 sq mi), and had an official population of 172 persons as of the 2010 census. There are four villages on Olosega:

Olosega Ofu and Olosega are parts of a volcanic doublet in the Manuʻa Islands, which is a part of American Samoa in the Samoan Islands. These twin islands, formed from shield volcanoes, have a combined length of 6 km and a combined area of . Together, ...

Lalomoana Lalomoana is a small settlement located in Olosega island in Ofu-Olosega on the slopes on Piumafua, in Manu‘a Group of the Samoan Islands—part of American Samoa American Samoa ( sm, Amerika Sāmoa, ; also ' or ') is an unincorporated ...

, Sili, and Faiava.

Gallery

File:Ofu_Beach_American_Samoa_US_National_Park_Service.jpg File:AmSamoa_Ofu_442.jpg File:Olosega Aerial AKK.jpg File:Coralandbeach.jpg File:Snoutsand2.jpg File:Curvedpalm.jpg

References

External links

* 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. *
National Park Service map of the Manu‘a Islands

G. Piniak, C. Birkeland, and G. Garrison (2004). University of Hawaii. {{American Samoa Islands of American Samoa Mountains of American Samoa Volcanoes of American Samoa Polygenetic shield volcanoes Manu'a