Vailulu'u
Encyclopedia
Vailulu'u is a volcanic
seamount
discovered by geophysicist Rockne Johnson in the Samoa Islands on October 18, 1975. The finding of an active, undersea, hotspot
volcano is significant for scientists studying the Earth's fundamental processess.
In size and appearance, Vaululu'u resembles Mt Fuji and ranges more than 33km across the ocean floor at its base.It rises 4200 m from the sea floor to a depth of 590 m. It is located roughly one-third of the way between Ta'u
and Rose
islands at the eastern end of the Samoa hotspot
chain. The hotspot chain include American Samoa
and the Independent State of Samoa
and extends west to the islands of Uvea or Wallis Island
(Wallis and Futuna) and Niulakita
(Tuvalu
).
The basalt
ic seamount, is considered to mark the current location of the Samoa hotspot. The summit of Vailulu'u contains a 2 km wide, 400-m-deep oval-shaped caldera
. Two principal rift zones extend east and west from the summit, parallel to the trend of the Samoan hotspot. A third less prominent rift extends southeast of the summit.
The rift zones and escarpments produced by mass wasting phenomena give the sea mount a star-shaped pattern. On July 10, 1973, explosions from Vailulu'u were recorded by SOFAR
(hydrophone records of underwater acoustic signals). An earthquake swarm in 1995 may have been related to an eruption from the seamount. Turbid water above the summit shows evidence of ongoing hydrothermal plume activity.
Evidence released in 2006 suggest that Vailulu'u may breach the surface of the ocean and officially become an island during this century.
The name Vailulu'u comes from a Samoan story related to the sacred sprinkling of rain associated with gatherings for the Tui Manu'a
paramount chiefs of Manu'a Island. The name came from an American Samoa student Taulealo Vaofusi, the winner of a naming competition.
that has been growing inside the summit crater of Vailulu'u since 2001. In 2005 it was 300 m tall, but still 708 m below sea level. It is best known as the site of 'Eel City,' a hydrothermal vent
biological community consisting mainly of eel
s (rather than the usual invertebrate
s).
Nafanua
is also a war goddess in Samoan mythology
.
Volcano
2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...
seamount
Seamount
A seamount is a mountain rising from the ocean seafloor that does not reach to the water's surface , and thus is not an island. These are typically formed from extinct volcanoes, that rise abruptly and are usually found rising from a seafloor of depth. They are defined by oceanographers as...
discovered by geophysicist Rockne Johnson in the Samoa Islands on October 18, 1975. The finding of an active, undersea, hotspot
Hotspot (geology)
The places known as hotspots or hot spots in geology are volcanic regions thought to be fed by underlying mantle that is anomalously hot compared with the mantle elsewhere. They may be on, near to, or far from tectonic plate boundaries. There are two hypotheses to explain them...
volcano is significant for scientists studying the Earth's fundamental processess.
In size and appearance, Vaululu'u resembles Mt Fuji and ranges more than 33km across the ocean floor at its base.It rises 4200 m from the sea floor to a depth of 590 m. It is located roughly one-third of the way between Ta'u
Tau, American Samoa
Ta‘ū is the largest island in the Manu‘a Group and the easternmost volcanic island of the Samoan Islands. Ta‘ū is part of American Samoa. In the early 19th century, the island was sometimes called Opoun....
and Rose
Rose Atoll
Rose Atoll, sometimes called Rose Island or Motu O Manu by people of the nearby Manu'a Islands, is an oceanic atoll within the U.S. territory of American Samoa. It is an uninhabited wildlife refuge. It is the southernmost point in the United States. The land area is 0.214 km²...
islands at the eastern end of the Samoa hotspot
Samoa hotspot
The Samoa hotspot is a volcanic hotspot located in the south Pacific Ocean.In geology the Hotspot model describes a hot upwelling plume of molten magma through the Earth's crust as an explanation of how volcanic islands are formed. The hotspot idea came from J...
chain. The hotspot chain include American Samoa
American Samoa
American Samoa is an unincorporated territory of the United States located in the South Pacific Ocean, southeast of the sovereign state of Samoa...
and the Independent State of Samoa
Samoa
Samoa , officially the Independent State of Samoa, formerly known as Western Samoa is a country encompassing the western part of the Samoan Islands in the South Pacific Ocean. It became independent from New Zealand in 1962. The two main islands of Samoa are Upolu and one of the biggest islands in...
and extends west to the islands of Uvea or Wallis Island
Wallis Island
Wallis is an island in the Pacific Ocean belonging to the French overseas collectivity of Wallis and Futuna....
(Wallis and Futuna) and Niulakita
Niulakita
Niulakita is the southernmost reef island, which is a district of Tuvalu, and the name of the only village on this island. The junior school is Lotoalofa Primary School.-Geographical features:...
(Tuvalu
Tuvalu
Tuvalu , formerly known as the Ellice Islands, is a Polynesian island nation located in the Pacific Ocean, midway between Hawaii and Australia. Its nearest neighbours are Kiribati, Nauru, Samoa and Fiji. It comprises four reef islands and five true atolls...
).
The basalt
Basalt
Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...
ic seamount, is considered to mark the current location of the Samoa hotspot. The summit of Vailulu'u contains a 2 km wide, 400-m-deep oval-shaped caldera
Caldera
A caldera is a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption, such as the one at Yellowstone National Park in the US. They are sometimes confused with volcanic craters...
. Two principal rift zones extend east and west from the summit, parallel to the trend of the Samoan hotspot. A third less prominent rift extends southeast of the summit.
The rift zones and escarpments produced by mass wasting phenomena give the sea mount a star-shaped pattern. On July 10, 1973, explosions from Vailulu'u were recorded by SOFAR
Sofar
Sofar may refer to:* Sofar bomb , a long-range position-fixing system that uses explosive sounds in the deep sound channel of the ocean...
(hydrophone records of underwater acoustic signals). An earthquake swarm in 1995 may have been related to an eruption from the seamount. Turbid water above the summit shows evidence of ongoing hydrothermal plume activity.
Evidence released in 2006 suggest that Vailulu'u may breach the surface of the ocean and officially become an island during this century.
The name Vailulu'u comes from a Samoan story related to the sacred sprinkling of rain associated with gatherings for the Tui Manu'a
Tui Manu'a
An ancient prodominant title of the Manu'a islands of the Samoa Islands , which are now part of the United States Territory of American Samoa...
paramount chiefs of Manu'a Island. The name came from an American Samoa student Taulealo Vaofusi, the winner of a naming competition.
Nafanua
Nafanua is an active underwater volcanic coneVolcanic cone
Volcanic cones are among the simplest volcanic formations. 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 size of the fragments ejected during the eruption...
that has been growing inside the summit crater of Vailulu'u since 2001. In 2005 it was 300 m tall, but still 708 m below sea level. It is best known as the site of 'Eel City,' a hydrothermal vent
Hydrothermal vent
A hydrothermal vent is a fissure in a planet's surface from which geothermally heated water issues. Hydrothermal vents are commonly found near volcanically active places, areas where tectonic plates are moving apart, ocean basins, and hotspots. Hydrothermal vents exist because the earth is both...
biological community consisting mainly of eel
Eel
Eels are an order of fish, which consists of four suborders, 20 families, 111 genera and approximately 800 species. Most eels are predators...
s (rather than the usual invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s).
Nafanua
Nafanua
Nafanua is the name of the revered Goddess of War in Samoa and a deity in Polynesian Mythology.According to Samoan mythology, Nafanua was the daughter of Saveasi'uleo, the God of Pulotu, Samoa's spirit world. In one legend, Nafanua's mother was Tilafaiga the sister of Taema.-Background:Nafanua is a...
is also a war goddess in Samoan mythology
Samoan mythology
Samoan mythology tell stories of many different gods. There were gods of the forest, the seas, rain, harvest, villages and war. There were two types of gods, atua who had non-human origins and aitu who were of human origin. Tagaloa was a supreme god who made the islands and the people. Mafui'e was...
.
External links
- NOAA Ocean Explorer Vailulu'u 2005 Expedition, Retrieved 30 August 2007
- Vailulu'u web site, information about the Vailulu'u seamount