Vailuluʻu
Vailuluʻu | |
---|---|
Summit depth | 590 metres (1,940 ft) |
Height | 4,200 m (13,800 ft) |
Location | |
Location | South Pacific Ocean |
Coordinates | 14°12′54″S 169°3′30″W / 14.21500°S 169.05833°W |
Country | United States |
Geology | |
Last eruption | 2003 |
History | |
Discovery date | 1975 |
Vailuluʻu is a
Eruptions at Vailuluʻu were recorded in 1973. 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. Vailuluʻu may breach the surface of the ocean and officially become an island if a high rate of eruptions continue.
Name and research history
The seamount was first discovered in 1975
Geography and geomorphology
Vailuluʻu is located east of
Vailuluʻu is a conical seamount[10] and reaches a depth of 593 metres (1,946 ft) and features a 2 kilometres (1.2 mi) wide and 0.4 kilometres (0.25 mi) deep crater;[1] the shallowest part of the seamount is located on the western crater rim[11] which has a scalloped appearance.[12] Two additional summits and three breaches can be found in the crater rim; the deepest breach lies in the southeast and is 795 metres (2,608 ft) deep.[13]
The seamount has a star-like shape, with two prominent ridges east and west and a somewhat less prominent ridge south of the volcano; it also features smaller ridges at its foot and amphitheatre-shaped scars from landslides.[12] The total volume of the volcano is estimated to be about 1,050 cubic kilometres (250 cu mi)[3] and its height above the seafloor is comparable with that of major isolated volcanoes such as Fuji, although much smaller than compound volcanic islands such as Hawaii.[14] The seafloor around Vailuluʻu lies at a depth of about 5 kilometres (3.1 mi);[1] the foot of the seamount has a diameter of about 35 kilometres (22 mi). A saddle at a depth of 3,200 metres (10,500 ft) depth connects it to Taʻu.[3]
A 300 metres (980 ft) high cone in the crater bears the name Nafanua, and formed in 2004[1] in the western half of the crater.[15] Prior to the formation of the cone, the crater contained several pit craters;[12] it is possible that the crater was once occupied by a higher cone, which might have risen to shallow depths.[16] The Nafanua cone consists mostly of pillow lavas.[17]
Hydrothermal vents
The hydrothermal fluids vented at the Northern Moat Hydrothermal Complex appear to be rich in sulfides,[7] and droplets of carbon dioxide have been observed in the vented fluids.[15] Particles emitted by the vents in some places reduce visibility underwater to less than 2 metres (6 ft 7 in),[1] and the vented fluids are subject to complicated buoyancy, ocean current and mixing processes once they enter the seawater.[19]
The total flow is estimated at 0.13 cubic kilometres per day (1,500 m3/s). The total power of the hydrothermal system is estimated to be 610-760
Geology
Vailuluʻu lies at the eastern end of the Samoan volcanic chain
Samoa is located just northeast of the northern corner of the
The origin of the Samoan volcanic chain has been explained with either a hotspot influenced by the Tonga Trench or by cracking of the Pacific crust;[25] today the preferred theory is that the Samoan chain is a hotspot-generated volcanic chain while the "anomalous" younger volcanism is produced through an interaction between the islands and the Tonga Trench and a neighboring transform fault.[26] This hotspot is under the influence of the mantle flows triggered by the Tonga Trench, which distort the rising plume[23] and also changes its upwelling flux.[28] This interaction has only begun recently.[29]
Composition
Evidence of hydrothermal alteration includes quartz in rock samples.[32] Iron oxide chimneys with sizes measured in centimetres to metres[19] have been formed by low temperature hydrothermal venting. A total mass flux of 5.5 tonnes per day (0.063 long ton/ks) of manganese has been estimated.[1] Hydrothermal sulfide and oxide deposits may become targets for mining.[33]
Biology
Various
Sulfur, manganese and iron may serve as electron donors in organism metabolism at Vailuluʻu;[39] hydrogen sulfide, iron, manganese and methane-oxidizing Gammaproteobacteria have been encountered.[40]
There are differences between the animal fauna in various parts of the volcano. For example, the oxygenated waters and availability of shrimp as food source attract eels to the summit of Nafanua, while the crater floor[1] displays a high animal mortality and is called the "moat of death";[11] polychaetes feeding on dead fish have been found on the crater floor.[40] This is due to the very low availability of oxygen for respiration at the crater floor, unlike at the summit of Nafanua cone.[39]
Eruption history
Vailuluʻu is an active volcano, with earthquakes, volcanic eruptions and hydrothermal activity recorded.
Disequilibria in thorium and uranium isotopes of rock samples taken from the seamount indicate that Vailuluʻu was frequently active in the last 8,000 years[49][48] and that eruptions within the summit crater took place in the last hundred years.[50] Dredge samples showed fresh rocks; radiometric dating produced ages of less than ten years according to 1984 and 1999 publications.[51]
The seismic swarm in 1973 appears to have been a major submarine eruption.[46] The last eruption, between 2001 and 2004, went unobserved[24] and formed the Nafanua volcanic cone;[48] for the most part, the shape of the volcano has not changed over time.[52] Repeated eruptions like the one that formed Nafanua could cause Vailuluʻu to emerge from the sea.[17] The summit of Vailuluʻu is shallow enough that explosive eruptions may occur which can affect coastal communities and ships.[14] It appears that isostatic effects from the growth of the seamount may have altered shorelines on Tutuila.[53]
Gallery
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The summit of Nafanua is covered with thick microbial mats, indicative of low-temperature venting
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Broken pillow lavas, colored red by iron oxide, inside Vailuluʻu crater.
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An octopus living on the western summit of Vailulʻu
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Swimming elasipod sea cucumber, Paleopatides sp., photographed off the northern shore of Tau Island, Vailuluʻu Expedition 2005
References
- ^ a b c d e f g h i j Connell et al. 2009, p. 598.
- ^ a b Hart et al. 2000, p. 3.
- ^ a b c d Hart et al. 2000, p. 5.
- ^ Lippsett, Lonny (1 June 2001). "Voyage to Vailulu'u". Oceanus. Retrieved 27 July 2023.
- ^ Young et al. 2006, p. 6453.
- NOAA. Retrieved 8 February 2019.
- ^ a b c d e Sudek et al. 2009, p. 582.
- ^ a b Sims et al. 2008, p. 3.
- ^ a b c d e Workman et al. 2004, p. 5.
- ^ a b c Koppers et al. 2010, p. 164.
- ^ a b Sudek et al. 2009, p. 583.
- ^ a b c d Hart et al. 2000, p. 6.
- ^ Staudigel et al. 2004, p. 3.
- ^ a b Konter et al. 2004, p. 2.
- ^ a b c Connell et al. 2009, p. 599.
- ^ a b Young et al. 2006, p. 6449.
- ^ a b Young et al. 2006, p. 6448.
- ^ Staudigel et al. 2004, p. 19.
- ^ a b c Young et al. 2006, p. 6450.
- ISSN 2156-2202.
- ^ Hart et al. 2000, p. 10.
- ^ Sims et al. 2008, p. 13.
- ^ a b Sims et al. 2008, p. 14.
- ^ a b Koppers et al. 2011, p. 3.
- ^ a b c Konter et al. 2004, p. 3.
- ^ a b Hart et al. 2004, p. 38.
- ^ Sims et al. 2008, p. 2.
- ^ Sims et al. 2008, p. 20.
- ^ Hart et al. 2004, p. 52.
- ^ Workman et al. 2004, p. 9.
- ^ Sims et al. 2008, p. 6.
- ^ Workman et al. 2004, p. 6.
- ^ Hein, James R.; McIntyre, Brandie R.; Piper, David Z. (2005). "Marine Mineral Resources of Pacific Islands - A Review of the Exclusive Economic Zones of Islands of U.S. Affiliation, Excluding the State of Hawaii". U.S. Geological Survey Circular 1286: 10. Retrieved 2019-02-08.
- ^ Sudek et al. 2009, p. 592.
- ^ Connell et al. 2009, p. 601.
- ^ Connell et al. 2009, p. 604.
- ^ Sudek et al. 2009, p. 581.
- ^ Sudek et al. 2009, p. 590.
- ^ a b c Sudek et al. 2009, p. 593.
- ^ a b c Koppers et al. 2010, p. 165.
- ^ a b Young et al. 2006, p. 6451.
- ^ Young et al. 2006, pp. 6451–6452.
- PMID 38036504.
- NOAA. Retrieved 8 February 2019.
- ^ Young et al. 2006, p. 6452.
- ^ a b Konter et al. 2004, p. 4.
- ^ Konter et al. 2004, p. 14.
- ^ a b c Koppers et al. 2011, p. 5.
- ^ Sims et al. 2008, p. 12.
- ^ Sims et al. 2008, p. 21.
- ^ Hart et al. 2000, p. 7.
- ^ Hart et al. 2000, pp. 5–6.
- ISSN 0169-555X.
Sources
- Connell, Laurie; Barrett, Anne; Templeton, Alexis; Staudigel, Hubert (30 November 2009). "Fungal Diversity Associated with an Active Deep Sea Volcano: Vailuluʻu Seamount, Samoa". Geomicrobiology Journal. 26 (8): 597–605. S2CID 128549578.
- Hart, S. R.; Coetzee, M.; Workman, R. K.; Blusztajn, J.; Johnson, K. T. M.; Sinton, J. M.; Steinberger, B.; Hawkins, J. W. (30 October 2004). "Genesis of the Western Samoa seamount province: age, geochemical fingerprint and tectonics". Earth and Planetary Science Letters. 227 (1): 37–56. ISSN 0012-821X.
- Hart, S. R.; Staudigel, H.; Koppers, A. a. P.; Blusztajn, J.; Baker, E. T.; Workman, R.; Jackson, M.; Hauri, E.; Kurz, M. (2000). "Vailuluʻu undersea volcano: The New Samoa". Geochemistry, Geophysics, Geosystems. 1 (12): n/a. ISSN 1525-2027.
- Konter, J. G.; Staudigel, H.; Hart, S. R.; Shearer, P. M. (2004). "Seafloor seismic monitoring of an active submarine volcano: Local seismicity at Vailuluʻu Seamount, Samoa" (PDF). Geochemistry, Geophysics, Geosystems. 5 (6): Q06007. ISSN 1525-2027.
- Koppers, Anthony; Staudigel, Hubert; Hart, Stanley; Young, Craig; Konter, Jasper (1 March 2010). "Spotlight: Vailuluʻu Seamount". Oceanography. 23 (1): 164–165. hdl:1912/3549.
- Koppers, Anthony A. P.; Russell, Jamie A.; Roberts, Jed; Jackson, Matthew G.; Konter, Jasper G.; Wright, Dawn J.; Staudigel, Hubert; Hart, Stanley R. (July 2011). "Age systematics of two young en echelon Samoan volcanic trails". Geochemistry, Geophysics, Geosystems. 12 (7): n/a. S2CID 54947952.
- Sims, Kenneth W. W.; Hart, S. R.; Reagan, M. K.; Blusztajn, J.; Staudigel, H.; Sohn, R. A.; Layne, G. D.; Ball, L. A.; Andrews, J. (2008). "238U-230Th-226Ra-210Pb-210Po, 232Th-228Ra, and 235U-231Pa constraints on the ages and petrogenesis of Vailuluʻu and Malumalu Lavas, Samoa". Geochemistry, Geophysics, Geosystems. 9 (4): n/a. S2CID 54637043.
- Staudigel, H.; Hart, S. R.; Koppers, A. a. P.; Constable, C.; Workman, R.; Kurz, M.; Baker, E. T. (2004). "Hydrothermal venting at Vailuluʻu Seamount: The smoking end of the Samoan chain". Geochemistry, Geophysics, Geosystems. 5 (2): n/a. S2CID 53631888.
- Sudek, Lisa A.; Templeton, Alexis S.; Tebo, Bradley M.; Staudigel, Hubert (30 November 2009). "Microbial Ecology of Fe (hydr)oxide Mats and Basaltic Rock from Vailuluʻu Seamount, American Samoa". Geomicrobiology Journal. 26 (8): 581–596. S2CID 85954222.
- Workman, R. K.; Hart, S. R.; Jackson, M.; Regelous, M.; Farley, K. A.; Blusztajn, J.; Kurz, M.; Staudigel, H. (2004). "Recycled metasomatized lithosphere as the origin of the Enriched Mantle II (EM2) end-member: Evidence from the Samoan Volcanic Chain". Geochemistry, Geophysics, Geosystems. 5 (4): n/a. S2CID 13987904.
- Young, Craig M.; Zierenberg, Robert; Templeton, Alexis S.; Tebo, Bradley M.; Pietsch, Theodore W.; Lee, Ray; Konter, Jasper; Koppers, Anthony A. P.; Jones, Daniel (2006-04-25). "Vailuluʻu Seamount, Samoa: Life and death on an active submarine volcano". Proceedings of the National Academy of Sciences. 103 (17): 6448–6453. PMID 16614067.
External links
- Herrera, Santiago; Chadwick, William W.; Jackson, Matthew G.; Konter, Jasper; McCartin, Luke; Pittoors, Nicole; Bushta, Emily; Merle, Susan G. (2023). "From basalt to biosphere: Early non-vent community succession on the erupting Vailulu'u deep seamount". Frontiers in Marine Science. 10. ISSN 2296-7745.
- NOAA Ocean Explorer Vailuluʻu 2005 Expedition, Retrieved 30 August 2007
- Vailuluʻu web site, information about the Vailuluʻu seamount
- "Vailuluʻu". Global Volcanism Program. Smithsonian Institution.