World Library  
Flag as Inappropriate
Email this Article

Lōʻihi Seamount

ʻihi Seamount
The island of Hawaii, showing Loihi's position southeast of the main landmass
Yellow rocks underwater with a few red and green regions
Yellow iron oxide-covered lava rock on the flank of Lōʻihi
Summit depth 975 m (3,199 ft).[1]
Height over 3,000 m (10,000 ft) above the ocean floor[2]
Translation Loʻihi means "long" in Hawaiian,[3] so named in 1955.[4](Hawaiian)
Location Southeast of the island of Hawaiʻi
Coordinates [1]
Country Hawaiʻi, US
Type Submarine volcano
Volcanic arc/chain Hawaiian-Emperor seamount chain
Age of rock At least 400,000 years old[5]
Last eruption February to August 1996[4]
Discovery date 1940 – US Coast and Geodetic Survey chart number 4115[5]
First visit 1978[5]

ʻihi Seamount is an active submarine volcano located around 35 km (22 mi) off the southeast coast of the island of Hawaiʻi[6] about 975 m (3,000 ft) below sea level. This seamount lies on the flank of Mauna Loa, the largest shield volcano on Earth. Lōʻihi meaning "long" in Hawaiian, is the newest volcano in the Hawaiian-Emperor seamount chain, a string of volcanoes that stretches over 5,800 km (3,600 mi) northwest of Lōʻihi. Unlike most active volcanoes in the Pacific Ocean that make up the active plate margins on the Pacific Ring of Fire, Lōʻihi and the other volcanoes of the Hawaiian-Emperor seamount chain are hotspot volcanoes and formed well away from the nearest plate boundary. Volcanoes in the Hawaiian Islands arise from the Hawaiʻi hotspot, and as the youngest volcano in the chain, Lōʻihi is the only Hawaiian volcano in the deep submarine preshield stage of development.

ʻihi began forming around 400,000 years ago and is expected to begin emerging above sea level about 10,000–100,000 years from now. At its summit, Lōʻihi Seamount stands more than 3,000 m (10,000 ft) above the seafloor, making it taller than Mount St. Helens was before its catastrophic 1980 eruption. The summit is currently 975 m (3,000 ft) below sea level. A diverse microbial community resides around Lōʻihi's many hydrothermal vents.

In the summer of 1996, a swarm of 4,070 earthquakes was recorded at Lōʻihi. This series included more earthquakes than any other swarm in Hawaiian recorded history. The swarm altered 10 to 13 square kilometres (4 to 5 sq mi) of the seamount's summit; one section, Pele's Vents, collapsed entirely upon itself and formed the renamed Pele's Pit. The volcano has remained relatively active since the 1996 swarm and is monitored by the National Oceanic and Atmospheric Administration (NOAA) and the United States Geological Survey (USGS). The Hawaii Undersea Geological Observatory (HUGO) provided real-time data on Lōʻihi between 1997 and 2002. Lōʻihi last erupted in 1996, before the earthquake swarm of that summer.


  • Characteristics 1
    • Geology 1.1
    • Age and growth 1.2
  • Activity 2
    • 1996 earthquake swarm 2.1
    • Recent activity 2.2
  • Exploration 3
    • Early work 3.1
    • 1996 to present 3.2
  • Ecology 4
    • Hydrothermal vent geochemistry 4.1
    • Microorganisms 4.2
    • Macroorganisms 4.3
  • See also 5
  • References 6
  • Further reading 7
  • External links 8



ʻihi is a seamount, or underwater volcano, on the flank of Mauna Loa, the Earth's largest shield volcano. It is the newest volcano created by the Hawaiʻi hotspot in the extensive Hawaiian-Emperor seamount chain. The distance between the summit of the older Mauna Loa and the summit of Lōʻihi is about 80 km (50 mi), which is, coincidentally, also the approximate diameter of the Hawaiʻi hotspot.[4]ʻihi consists of a summit area with three pit craters, an 11 km (7 mi) long rift zone extending north from the summit, and a 19 km (12 mi) long rift zone extending south-southeast from the summit.[7]

The summit's pit craters are named West Pit, East Pit, and Pele's Pit.[8] Pele's Pit is the youngest of this group and is located at the southern part of the summit. The walls of Pele's Pit stand 200 m (700 ft) high and were formed in July 1996 when its predecessor, Pele's Vent, a hydrothermal field near Lōʻihi's summit, collapsed into a large depression.[6] The thick crater walls of Pele's Pit—averaging 20 m (70 ft) in width, unusually thick for Hawaiian volcanic craters—suggest its craters have filled with lava multiple times in the past.[9]

Map of a north–south ridge, trending slightly east of south. Draws lines through areas of a given water depth with an arrow pointing to Pele's Pit. At its peak, Pele's pit is about 1,000 meters below sea level; further south the ridge gradually descends about 3,500 metres to the sea floor.
Bathymetric mapping of Lōʻihi; the arrow points to Pele's Pit.

ʻihi's north–south trending rift zones create a distinctive elongated shape, from which the volcano's Hawaiian name, meaning "long", derives.[10] The north rift zone consists of a longer western portion and a shorter eastern rift zone. Observations show that both the north and south rift zones lack sediment cover, indicating recent activity. A bulge in the western part of the north rift zone contains three 60–80 m (200–260 ft) cone-shaped prominences.[9]

Until 1970, Lōʻihi was thought to be an inactive volcano that had been transported to its current location by sea-floor spreading. The seafloor under Hawaiʻi is 80–100 million years old and was created at the East Pacific Rise, an oceanic spreading center where new sea floor forms from magma that erupts from the mantle. New oceanic crust moves away from the spreading center. Over a period of 80–100 million years, the sea floor under Hawaiʻi moved from the East Pacific Rise to its present location 6,000 km (4,000 mi) west, carrying ancient seamounts with it. When scientists investigated a series of earthquakes off Hawaiʻi in 1970, they discovered that Lōʻihi was an active member of the Hawaiian-Emperor seamount chain.

3D map of Lōʻihi
Three dimensional rendering of the Seamount

3D map of Lōʻihi

ʻihi is built on the seafloor with a slope of about five degrees. Its northern base on the flank of Mauna Loa is 1,900 m (6,200 ft) below sea level, but its southern base is a more substantial 4,755 m (15,600 ft) below the surface. Thus, the summit is 931 m (3,054 ft) above the seafloor as measured from the base of its north flank, but 3,786 m (12,421 ft) high when measured from the base of its southern flank.[4]

ʻihi is following the pattern of development that is characteristic of all Hawaiʻian volcanoes. Geochemical evidence from Lōʻihi lavas indicates that Lōʻihi is in transition between the preshield and shield volcano stage, providing valuable clues to the early development of Hawaiian volcanoes. In the preshield stage, Hawaiian volcanoes have steeper sides and a lower level of activity, producing an alkali basalt lava.[11][12] Continued volcanism is expected to eventually create an island at Lōʻihi. Lōʻihi experiences frequent landslides; the growth of the volcano has destabilized its slopes, and extensive areas of debris inhabit the steep southeastern face. Similar deposits from other Hawaiian volcanoes indicate that landslide debris is an important product of Hawaiian volcanos' early development.[5]ʻihi is predicted to rise above the surface in 10,000 to 100,000 years.[1]

Age and growth

Radiometric dating was used to determine the age of rock samples from Lōʻihi. The Hawaii Center for Volcanology tested samples recovered by various expeditions, notably the 1978 expedition, which provided 17 dredge samples. Most of the samples were found to be of ancient origin; the oldest dated rock is around 300,000 years old. Following the 1996 event, some young breccia was also collected. Based on the samples, scientists estimate Lōʻihi is about 400,000 years old. The rock accumulates at an average rate of 3.5 mm (0.14 in) per year near the base, and 7.8 mm (0.31 in) near the summit. If the data model from other volcanoes such as Kīlauea holds true for Lōʻihi, 40% of the volcano's mass formed within the last 100,000 years. Assuming a linear growth rate, Lōʻihi is 250,000 years old. However, as with all hotspot volcanoes, Lōʻihi's level of activity has increased with time; therefore, it would take at least 400,000 years for such a volcano to reach Lōʻihi's mass.[5] As Hawaiian volcanoes drift northwest at a rate of about 10 cm (4 in) a year, Lōʻihi was 40 km (25 mi) southeast of its current position at the time of its initial eruption.[13]


ʻihi is a young and fairly active volcano, although less active than nearby Kīlauea. In the past few decades, several earthquake swarms have been attributed to Lōʻihi, the largest of which are summarized in the table below.[14] The volcano's activity is now known to predate scientific record keeping of its activity, which commenced in 1959.[15] Most earthquake swarms at Lōʻihi have lasted less than two days; the two exceptions are the 1991–92 earthquake, lasting several months, and the 1996 event, which was shorter but much more pronounced. Both of the earthquakes followed a pattern of activity that began on the flank and migrated to the summit. The 1996 event was directly observed by an autonomous ocean bottom observatory (OBO), allowing scientists to calculate the depth of the earthquakes as 6 km (4 mi) to 8 km (5 mi) below the summit, approximating to the position of Lōʻihi's extremely shallow magma chamber.[5] This is evidence that Lōʻihi's seismicity is volcanic in origin.[8]

The low-level seismic activity documented on Lōʻihi since 1959 has shown that between two and ten earthquakes per month are traceable to the summit.[15] Earthquake swarm data have been used to analyze how well Lōʻihi's rocks propagate seismic waves and to investigate the relationship between earthquakes and eruptions. This low level activity is periodically punctuated by large swarms of earthquakes, each swarm comprising up to hundreds of earthquakes. The majority of the earthquakes are not distributed close to the summit, though they follow a north–south trend. Rather, most of the earthquakes occur in the southwest portion of Lōʻihi.[5] The largest recorded swarms took place on Lōʻihi in 1971, 1972, 1975, 1991–92 and 1996. The nearest seismic station is around 30 km (20 mi) from Lōʻihi, on the south coast of Hawaiʻi. Seismic events that have a magnitude under 2 are recorded often, but their location cannot be determined precisely as it can for larger events.[16] In fact, HUGO (Hawaiʻi Undersea Geological Observatory), positioned on Lōʻihi's flank, detected ten times as many earthquakes as were recorded by the Hawaiian Volcano Observatory (HVO) seismic network.[5]

1996 earthquake swarm

Major Events Year(s) Summary
Evidence of eruption in early 1996, and large, well-recorded earthquake swarm in the summer. Started on February 25, 1996, and lasted until August 9, 1996.[16][17]
An OBO positioned on the seamount to track a recent earthquake swarm collected evidence of deflation, possibly due to magma withdrawal.[5]
Possible eruption, occurred on September 20, 1986 (one day).[17]
Nine events of magnitude 3 or greater, measuring between 3.0 and 4.2, were recorded from November 11, 1984, to January 21, 1985.[16] Eruption possible, but uncertain.[17]
Prominent earthquake swarm from August 24, 1975, to November 1975.[17]
Possible eruption from September 17, 1971, to September 1972.[17] Eruption uncertain.
An earthquake swarm on Lōʻihi in 1952 was the event that first brought attention to the volcano, previously thought extinct.[5]
50 BC
± 1000
Confirmed ancient eruption[17]
5050 BC
± 1000
Confirmed ancient eruption[17]
7050 BC
± 1000
Confirmed ancient eruption, most likely on the east flank[16]
This table indexes only possible volcanic eruptions and major events. Lōʻihi has also been the site of multiple earthquake swarms occurring on a nearly semi-annual basis.

The largest amount of activity recorded for the Lōʻihi seamount was a swarm of 4,070 earthquakes between July 16 and August 9, 1996.[4] This series of earthquakes was the largest recorded for any Hawaiian volcano to date in both amount and intensity. Most of the earthquakes had moment magnitudes of less than 3.0. "Several hundred" had a magnitude greater than 3.0, including more than 40 greater than 4.0 and a 5.0 tremor.[16][18]

The final two weeks of the earthquake swarm were observed by a quick response cruise launched in August 1996. The National Science Foundation funded an expedition by University of Hawaiʻi scientists, led by Frederick Duennebier, that began investigating the swarm and its origin in August 1996. The scientists' assessment laid the groundwork for many of the expeditions that followed.[19] Follow-up expeditions to Lōʻihi took place, including a series of manned-submersible dives in August and September. These were supplemented by a great deal of shore-based research.[18] Fresh rock collected during the expedition revealed that an eruption occurred before the earthquake swarm.[20]

Submersible dives in August were followed by NOAA-funded research in September and October 1996. These more detailed studies showed the southern portion of Lōʻihi's summit had collapsed, a result of a swarm of earthquakes and the rapid withdrawal of magma from the volcano. A crater 1 km (0.6 mi) across and 300 m (1,000 ft) deep formed out of the rubble. The event involved the movement of 100 million cubic meters of volcanic material. A region of 10 to 13 km2 (4 to 5 sq mi) of the summit was altered and populated by bus-sized pillow lava blocks, precariously perched along the outer rim of the newly formed crater. "Pele's Vents," an area on the southern side, previously considered stable, collapsed completely into a giant pit, renamed "Pele's Pit". Strong currents make submersible diving hazardous in the region.[19]

The researchers were continually met by clouds of sulfide and sulfate. The sudden collapse of Pele's Vents caused a large discharge of hydrothermal material. The presence of certain indicator minerals in the mixture suggested temperatures exceeded 250 °C, a record for an underwater volcano. The composition of the materials was similar to that of black smokers, the hydrothermal vent plumes located along mid-ocean ridges. Samples from mounds built by discharges from the hydrothermal plumes resembled white smokers.[21]

The studies demonstrated that the most volcanically and hydrothermally active area was along the southern rift. Dives on the less active northern rim indicated that the terrain was more stable there, and high lava columns were still standing upright.[19] A new hydrothermal vent field (Naha Vents) was located in the upper-south rift zone, at a depth of 1,325 m (4,350 ft).[5][22]

Recent activity

ʻihi has remained largely quiet since the 1996 event; no activity was recorded from 2002 to 2004. The seamount showed signs of life again in 2005 by generating an earthquake bigger than any previously recorded there. USGS-ANSS (Advanced National Seismic System) reported two earthquakes, magnitudes 5.1 and 5.4, on May 13 and July 17. Both originated from a depth of 44 km (27 mi). On April 23, a magnitude 4.3 earthquake was recorded at a depth of approximately 33 km (21 mi). Between December 7, 2005, and January 18, 2006, a swarm of around 100 earthquakes occurred, the largest measuring 4 on the Moment magnitude scale and 12 km (7 mi) to 28 km (17 mi) deep. Another earthquake measuring 4.7 was later recorded approximately midway between Lōʻihi and Pāhala (on the south coast of the island of Hawaiʻi).[14]


Early work

ʻihi Seamount's first depiction on a map was on Survey Chart 4115, a bathymetric rendering of part of Hawaiʻi compiled by the US Coast and Geodetic Survey in 1940. At the time, the seamount was non-notable, being one of many in the region. A large earthquake swarm first brought attention to it in 1952. That same year, geologist Gordon A. MacDonald hypothesized that the seamount was actually an active submarine shield volcano, similar to the two active Hawaiian volcanoes, Mauna Loa and Kīlauea. Macdonald's hypothesis placed the seamount as the newest volcano in the Hawaiian-Emperor seamount chain, created by the Hawaiʻi hotspot. However, because the earthquakes were oriented east–west (the direction of the volcanic fault) and there was no volcanic tremor in seismometers distant from the seamount, Macdonald attributed the earthquake to faulting rather than a volcanic eruption.[5]

A submarine, hanging from the back of a ship via a crane, is lowered into the water.
R/V (research vessel) Kaʻimikai-o-Kanaloa (KoK) launching Pisces V, a battery-powered submersible. The R/V KoK is the support ship for the Hawaiʻi Undersea Research Laboratory (HURL).

Geologists suspected the seamount could be an active undersea volcano, but without evidence the idea remained speculative. The volcano was largely ignored after the 1952 event, and was often mislabeled as an "older volcanic feature" in subsequent charts.[5] Geologist Kenneth O. Emery is credited with naming the seamount in 1955,[7] describing the long and narrow shape of the volcano as ʻihi, the Hawaiian word for "long".[10][26] In 1978, an expedition studied intense, repeated seismic activity known as earthquake swarms in and around the Lōʻihi area. Rather than finding an old, extinct seamount, data collected revealed Lōʻihi to be a young, possibly active volcano. Observations showed volcano to be encrusted with young and old lava flows as well as actively venting hydrothermal fluids.[2]

In 1978, a US Geological Survey research ship collected dredge samples and photographed Lōʻihi's summit with the goal of studying whether Lōʻihi is active. Analysis of the photos and testing of pillow lava rock samples appeared to show that the material was "fresh", yielding more evidence that Lōʻihi is still active. An expedition from October 1980 to January 1981 collected further dredge samples and photographs, providing additional confirmation.[27] Studies indicated that the eruptions came from the southern part of the rift crater. This area is closest to the Hawaiʻi hotspot, which supplies Lōʻihi with magma.[5] Following a 1986 seismic event, a network of five ocean bottom observatories (OBOs) were deployed on Lōʻihi for a month. Lōʻihi's frequent seismicity makes it an ideal candidate for seismic study through OBOs.[5] In 1987, the submersible DSV Alvin was used to surveyʻihi.[28] Another autonomous observatory was positioned on Lōʻihi in 1991 to track earthquake swarms.[5]

1996 to present

The bulk of information about Lōʻihi comes from dives made in response to the 1996 eruption. In a dive conducted almost immediately after seismic activity was reported, visibility was greatly reduced by high concentrations of displaced minerals and large floating mats of bacteria in the water. The bacteria that feed on the dissolved nutrients had already begun colonizing the new hydrothermal vents at Pele's Pit (formed from the collapse of the old ones), and may be indicators of the kinds of material ejected from the newly formed vents. They were carefully sampled for further analysis in a laboratory.[19] An OBO briefly sat on the summit before a more permanent probe could be installed.[29]

Repeated multibeam

  • Hawaii Center for Volcanology, University of Hawaiʻi.
  • ihi SeamountʻLo—USGS website.
  • Loihi Submarine Volcano: A unique, natural extremophile laboratory—NOAA research site.
  • HURL Current Research – Loihi after the July–August event, on the 1996 Lōʻihi Seamount Exploration
  • Recent volcanic activity at Loihi – University of Hawaiʻi
  • Fe-Oxidizing Microbial Observatory Project (FeMO) Webpage –

External links

  • Auerbach-Caplan, J.; F. Duennebier (2001-05-25). i Undersea Geo-Observatory"ʻihi Seamount by the Hawaiʻ"Seismic and acoustic signals detected at Lo (PDF). Geochemistry Geophysics Geosystems ( 
  • Chave, E. H.; Alexander Malahoff (1998). In Deeper Waters: Photographic Studies of Hawaiian Deep-sea Habitats and Life-forms. University of Hawaiʻi Press.  
  • F. K. Duennebier, N. C. Becker, J. Caplan-Auerbach, D. A. Clague, J. Cowen, M. Cremer, M. Garcia, F. Goff, A. Malahoff, G. M. McMurtry, B. P. Midson, C. L. Moyer, M. Norman, P. Okubo, J. A. Resing, J. M. Rhodes, K. Rubin, F. J. Sansone, J. R. Smith, K. Spencer, X. Wen, and C. G. Wheat (1997-06-03). i"ʻihi volcano, Hawaiʻ"Researchers rapidly respond to submarine activity at Lō (PDF).  
  • Emery, K.O. (1955). "Submarine topography south of Hawaiʻi".  
  • "Loihi – Data Sources".  
  • Klein, F. (1982). "Earthquakes at Lōʻihi submarine volcano and the Hawaiian hot spot". Journal of Geophysical Research 87: B9.  
  • Macdonald, G.A. (1952). "The South Hawaiʻi Earthquakes of March and April, 1952." The Volcano Letter. U.S. Geological Survey Professional Paper 515.
  • Malahoff, Alexander; Gary M. McMurtry; John C. Wiltshire; Hsueh-Wen Yeh (1982-07-15). i"ʻihi, Hawaiʻ"Geology and chemistry of hydrothermal deposits from active submarine volcano Lō.  
  • Malahoff, A.; Gregory, T.; Bossuyt, A.; Donachie, S.; Alarn, M. (Oct 2002). "A seamless system for the collection and cultivation of extremophiles from deep-ocean hydrothermal vents". IEEE Journal of Oceanic Engineering (IEEE Oceanic Engineering Society) 27 (4): 862–69.  
  • J.G. Moore, D.A. Clague, W.R. Normark (Feb 1982). "Diverse basalt types from Lōʻihi Seamount, Hawaiʻi". Geology (Geological Society of America) 10 (2): 88–92.  
  • Scripps Institution of Oceanography. (2002). Benthic Invertebrate Collection Database.

Further reading

  1. ^ a b c "Loihi".  
  2. ^ a b Rubin, Ken (2006-01-19). "General Information About Loihi". Hawaii Center for Volcanology.  
  3. ^ Pukui, M.K. & Elbert, S.H. Hawaiian Dictionary (1986) University of Hawaii Press ISBN 0-8248-0703-0
  4. ^ a b c d e i's Youngest Submarine Volcano"ʻihi Seamount Hawaiʻ"Lō. Hawaiian Volcano Observatory.  
  5. ^ a b c d e f g h i j k l m n o p q r s t Michael O. Garcia, Jackie Caplan-Auerbach, Eric H. De Carlo, M.D. Kurz, N. Becker (2005). i's youngest volcano"ʻihi Seamount, Hawaiʻ"Geochemistry, and Earthquake History of Lō ( 
  6. ^ a b c d e f g Malahoff, Alexander (2000-12-18). ihi Submarine Volcano: A unique, natural extremophile laboratory"ʻ"Lō.  
  7. ^ a b Malahoff, Alexander (1987). "Geology of the summit of Lōʻihi submarine volcano". In Decker, Robert W. Wright, Thomas L. Stauffer, Peter H. Volcanism in Hawaiʻi: U.S. Geological Survey Professional Paper 1350. United States Geological Survey Professional Paper 1350 1. Washington: United States Government Printing Office. pp. 133–44. Retrieved 2009-06-15. 
  8. ^ a b c Malahoff, Alexander; Kolotyrkina, Irina Ya.; Midson, Brian P.; Massoth, Gary J. (2006-01-06). "A decade of exploring a submarine intraplate volcano: Hydrothermal manganese and iron at Lō’ihi volcano, Hawai’i" (PDF). G3: Geochemistry, Geophysics, Geosystems ( 
  9. ^ a b Fornari, D.J., Garcia, M.O., Tyce, R.C., Gallo, D.G. (1988). "Morphology and structure of Loihi seamount based on seabeam sonar mapping". Journal of Geophysics Research 93 (15): 227–38.  
  10. ^ a b ʻihi, meaning "length, height, distance; long". See:  
  11. ^ Best, Myron G. (1991). Igneous and Metamorphic Petrology. Wiley, John & Sons, Incorporated. p. 359.  
  12. ^ "Evolution of Hawaiian Volcanoes". Hawaiian Volcano Observatory. USGS. September 8, 1995. Retrieved 2009-03-07. 
  13. ^ Garcia, M.O., Grooms, D., Naughton, J. (1987). "Petrology and geochronology of volcanic rocks". Lithosphere (The Geological Society of America) (20): 323–36. 
  14. ^ a b c Rubin, Ken (2006-01-20). "Recent Activity at Loihi Volcano – Updates on Geologic Activity at Loihi". Hawaii Center For Volcanology.  
  15. ^ a b Caplan-Auerbach, Jackie (1998-07-22). "Recent Seismicity at Loihi Volcano". Hawaii Center for Volcanology.  
  16. ^ a b c d e "Loihi – Monthly Reports".  
  17. ^ a b c d e f g "Loihi – Eruptive History".   Dates for older eruptions retrieved through Isotope dating.
  18. ^ a b Rubin, Ken (1998-07-22). "The 1996 Eruption and July–August Seismic Event". Hawaii Center for Volcanology.  
  19. ^ a b c d e f "HURL Current Research: Loihi after the July–August event". 1999 Research.  
  20. ^ Garcia, M.O., Graham, D.W., Muenow, D.W., Spencer, K., Rubin, K.H., Norman, M.D. (1998). "Petrology and geochronology of basalt breccia from the 1996 earthquake swarm of Loihi seamount, Hawaii: magmatic history of its 1996 eruption". Bulletin of Volcanology 59 (8): 577–92.  
  21. ^ a b Davis, Alicé S.; David A. Clague; Robert A. Zierenberg; C. Geoffrey Wheat; Brian L. Cousens (Apr 2003). "Sulfide formation related to changes in the hydrothermal system on Lōʻihi Seamount, Hawaiʻi, following the seismic event in 1996". The Canadian Mineralogist (Mineralogical Association of Canada) 41 (2): 57–472.  
  22. ^ a b c d e Rubin, Ken (1998-07-22). "Recent Activity at Loihi Volcano: Hydrothermal Vent and Buoyant Plume Studies". Hawaii Center for Volcanology.  
  23. ^ a b c d e f Rubin, Ken. ihi Since the 1996 Eruption and Seismic Swarm"ʻ"Cruises to Lō. Hawaiʻi Center for Volcanology.  
  24. ^ Duennebier, Fred (2002-10-01). "HUGO: Update and Current Status".  
  25. ^ a b c ihi Seamount"ʻ"Introduction to the Biology and Geology of Lō. ʻihi Seamount. Fe-Oxidizing Microbial Observatory (FeMO). 2009-02-01. Retrieved 2009-03-02. 
  26. ^ Cooke, Sarah (Apr 2002). ihi and the Hawaiian Hot Spot"ʻ"Lō. Caltech Undergraduate Research Journal ( 
  27. ^ Macdonald, Gordon A.; Agatin T. Abbott; Frank L. Peterson (1983) [1970]. Volcanoes in the Sea: The Geology of Hawaiʻi (2nd ed.). Honolulu: University of Hawaiʻi Press.  
  28. ^ Garcia, M.O., Irving, A.J., Jorgenson, B.A., Mahoney, J.J., Ito, E. (1993). "An evaluation of temporal geochemical evolution of Loihi summit lavas: results from Alvin submersible dives". Journal of Geophysical Research 98 (B1): 537–550.  
  29. ^ Bryan, Carol; Cooper, P. (December 1995). "Ocean-bottom seismometer observations of seismic activity at Loihi". Marine Geophysical Researches (Springer Netherlands) 17: 485–501.  
  30. ^ i Undersea Geo-Observatory"ʻ"HUGO: The Hawai.  
  31. ^ Emerson, David; Craig L. Moyer (June 2002). ihi Seamount Hydrothermal Vents and Play a Major Role in Fe Oxide Deposition"ʻ"Neutrophilic Fe-Oxidizing Bacteria Are Abundant at the Lō. Applied and Environmental Microbiology (American Society for Microbiology) 68 (6): 3085–93.  
  32. ^ Emerson, David; Rentz, Jeremy A.; Lilburn, Timothy G.; Davis, Richard E.; Aldrich, Henry; Chan, Clara; Moyer, Craig L. (2007). Reysenbach, Anna-Louise, ed. "A novel lineage of proteobacteria involved in formation of marine Fe-oxidizing microbial mat communities". PLoS ONE 2 (8): e667.  
  33. ^ "FeMO4 Dive Cruise 2009". FeMO. 2009-10-17. Retrieved 2010-02-08. 
  34. ^ Rubin, Ken (1998-09-07). "A Tour of Loihi". Hawaii Center for Volcanology.  
  35. ^ Rubin, Ken (1998-07-22). "Recent Activity at Loihi Volcano – 1996 Seismic/Volcanic Event Summary". Hawaii Center For Volcanology.  
  36. ^ a b Chave, E.H.; B.C. Mundy (1994). "Deep-Sea Benthic Fish of the Hawaiian Archipelago, Cross Seamount, and Johnston Atoll".  
  37. ^ Data from Chave, E.H. and B.C. Mundy (1994) and Scripps Institution of Oceanography (2002). "Observation Data".  


See also

From 1982 to 1992, researchers in Hawaiʻi Undersea Research Laboratory submersibles photographed the fish of Lōʻihi Seamount, Johnston Atoll, and Cross Seamount at depths between 40 m (130 ft) and 2,000 m (6,600 ft).[36][37] A small number of species identified at Lōʻihi were newly recorded sightings in Hawaiʻi, including the Tassled coffinfish (Chaunax fimbriatus), and the Celebes monkfish.[36]

Marine life inhabiting the waters around Lōʻihi is not as diverse as life at other, less active seamounts. Fish found living near Lōʻihi include the Celebes monkfish (Sladenia remiger), and members of the Cutthroat eel family, Synaphobranchidae.[34] Invertebrates identified in the area include two species endemic to the hydrothermal vents, a bresiliid shrimp (Opaepele loihi) of the family Alvinocarididae (described in 1995), and a tube or pogonophoran worm. Dives conducted after the 1996 earthquake swarms were unable to find either the shrimp or the worm, and it is not known if there are lasting effects on these species.[35]


NOAA's National Undersea Research Center and NSF's Marine Bioproducts Engineering Center are cooperating to sample and research the local bacteria and archaea extremophiles.[6] The fourth FeMO (Fe-Oxidizing Microbial Observatory) cruise occurred during October 2009.[33]

[19] A diverse community of

The vents lie 1,100 m (3,600 ft) to 1,325 m (4,347 ft) below the surface, and range in temperature from 10 to over 200 °C.[22][31] The vent fluids are characterized by a high concentration of CO
(up to 17 mM) and Fe (Iron), but low in sulfide. Low oxygen and pH levels are important factors in supporting the high amounts of Fe (iron), one of the hallmark features of Lōʻihi. These characteristics make a perfect environment for iron-oxidizing bacteria, called FeOB, to thrive in.[25] An example of these species is Mariprofundus ferrooxydans, sole member of the class Zetaproteobacteria.[32] The composition of the materials was similar to that of black smokers, that are a habitat of archaea extremophiles. Dissolution and oxidation of the mineral observed over the next two years suggests the sulfate is not easily preserved.[21]


ʻihi's mid-Pacific location and its well-sustained hydrothermal system contribute to a rich oasis for a microbial ecosystem. Areas of extensive hydrothermal venting are found on Lōʻihi's crater floor and north slope,[6] and along the summit of Lōʻihi itself. Active hydrothermal vents were first discovered at Lōʻihi in the late 1980s. These vents are remarkably similar to those found at the mid-ocean ridges, with similar composition and thermal differences. The two most prominent vent fields are at the summit: Pele's Pit (formally Pele's Vents) and Kapo's Vents. They are named after the Hawaiian deity Pele and her sister Kapo. These vents were considered "low temperature vents" because their waters were only about 30 °C. The volcanic eruption of 1996 and the creation of Pele's Pit changed this, and initiated high temperature venting; exit temperatures were measured at 77 °C in 1996.[22]

Vent[22] Depth Location Notes
Pele's 1,000 m (3,281 ft) Summit Destroyed 1996
Kapo's 1,280 m (4,199 ft) Upper South rift No longer venting
Forbidden 1,160 m (3,806 ft) Pele's Pit over 200 °C
Lohiau ("slow") 1,173 m (3,850 ft)[8] Pele's Pit 77 °C
Pahaku ("rocky") 1,196 m (3,924 ft) South rift zone 17 °C
Ula ("red") 1,099 m (3,606 ft) South summit Diffuse venting
Maximilian 1,249 m (4,098 ft) West summit flank Diffuse venting
Naha 1,325 m (4,347 ft) South rift 23 °C

Hydrothermal vent geochemistry


Since 2006, the Fe-Oxidizing Microbial Observatory (FeMO), funded by the National Science Foundation and Microbial Observatory Program, has led cruises to Lōʻihi investigate its microbiology every October. The first cruise, on the ship R/V Melville and exploiting the submersible JASON2, lasted from September 22 to October 9. These cruises study the large number of Fe-oxidizing bacteria that have colonized Lōʻihi. Lōʻihi's extensive vent system is characterized by a high concentration of CO2 and Iron, while being low in sulfide. These characteristics make a perfect environment for iron-oxidizing bacteria, called FeOB, to thrive in.[25]

In 1997, scientists from the University of Hawaiʻi installed an ocean bottom observatory (OBO) on the summit of Lōʻihi Seamount.[14] The submarine observatory was nicknamed HUGO, (Hawaiʻi Undersea Geological Observatory). HUGO was connected to the shore, 34 km (21 mi) away, by a fiber optic cable. It gave scientists real-time seismic, chemical and visual data about the state of Lōʻihi, which had by then become an international laboratory for the study of undersea volcanism.[19] The cable that provided HUGO with power and communications broke in October 1998, effectively shutting it down. On January 19 of the following year, HUGO was visited by Pisces V. The observatory functioned for four years before it went dead again in 2002.[30]

A small box-like robot positioned on orange rocks
Ocean bottom observatory (OBO) at Pele's Vents


This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Hawaii eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.