Submarine volcano

Submarine volcanoes are underwater vents or fissures in the Earth's surface from which magma can erupt. Many submarine volcanoes are located near areas of tectonic plate formation, known as mid-ocean ridges. The volcanoes at mid-ocean ridges alone are estimated to account for 75% of the magma output on Earth.[1] Although most submarine volcanoes are located in the depths of seas and oceans, some also exist in shallow water, and these can discharge material into the atmosphere during an eruption. The Kolumbo submarine volcano in the Aegean Sea was discovered in 1650 when it erupted, killing 70 people on the nearby island of Santorini. The total number of submarine volcanoes is estimated to be over 1 million (most are now extinct), of which some 75,000 rise more than 1 km above the seabed.[1]

Hydrothermal vents, sites of abundant biological activity, are commonly found near submarine volcanoes.

Submarine Eruption-numbers
Scheme of a submarine eruption.
1. Water vapor cloud
2. Water
3. Stratum
4. Lava flow
5. Magma conduit
6. Magma chamber
7. Dike
8. Pillow lava
Nur05018-Pillow lavas off Hawaii
Pillow lava formed by a submarine volcano
NOAA exploration video showing remnants of underwater tar volcanoes.

Effect of water on volcanoes

The presence of water can greatly alter the characteristics of a volcanic eruption and the explosions of underwater volcanoes in comparison to those on land.

For instance, water causes magma to cool and solidify much more quickly than in a terrestrial eruption, often turning it into volcanic glass. The shapes and textures of lava formed by submarine volcanoes are different from lava erupted on land. Upon contact with water, a solid crust forms around the lava. Advancing lava flows into this crust, forming what is known as pillow lava.

Below ocean depths of about 2200 m, where the pressure exceeds the critical pressure of water (22.06 MPa or about 218 atmospheres for pure water), it can no longer boil; it becomes a supercritical fluid. Without boiling sounds, deep-sea volcanoes can be difficult to detect at great distances using hydrophones.

The critical temperature and pressure increase in solutions of salts, which are normally present in the seawater. The composition of aqueous solution in the vicinity of hot basalt, and circulating within the conduits of hot rocks, is expected to differ from that of bulk water (i.e., of sea water away from the hot surfaces). One estimation is that the critical point is 407 °C and 29.9 MPa, while the solution composition corresponds to that of approximately 3.2% of NaCl.[2]

Research

Scientists still have much to learn about the location and activity of underwater volcanoes. In the first two decades of this century, NOAA's Office of Ocean Exploration has funded exploration of submarine volcanoes, with the Ring of Fire missions to the Mariana Arc in the Pacific Ocean being particularly noteworthy. Using Remote Operated Vehicles (ROV), scientists studied underwater eruptions, ponds of molten sulfur, black smoker chimneys and even marine life adapted to this deep, hot environment.

Research from the ROV KAIKO off the coast of Hawaii has suggested that pahoehoe lava flows occur underwater, and the degree of the submarine terrain slope and rate of lava supply determine the shape of the resulting lobes.[3]

Seamounts

Many submarine volcanoes are seamounts, typically extinct volcanoes that rise abruptly from a seafloor of 1,000 - 4,000 meters depth. They are defined by oceanographers as independent features that rise to at least 1,000 meters above the seafloor. The peaks are often found hundreds to thousands of meters below the surface, and are therefore considered to be within the deep sea.[4] An estimated 30,000 seamounts occur across the globe, with only a few having been studied. However, some seamounts are also unusual. For example, while the summits of seamounts are normally hundreds of meters below sea level, the Bowie Seamount in Canada's Pacific waters rises from a depth of about 3,000 meters to within 24 meters of the sea surface.

Identifying types of eruptions by sounds

Bands of glowing magma from submarine volcano
Deepest ever filmed submarine volcano, West Mata, May 2009.[5]

There are two types of submarine eruptions: One is created by the slow release and bursting of large lava bubbles, and the other one is created by a quick explosion of gas bubbles. Lava can affect marine animals and ecosystems differently than gas can, so it is important to be able to distinguish the two.

Scientists have been able to connect sounds to sights in both types of eruptions. In 2009, a video camera and a hydrophone were floating 1,200 meters below sea level in the Pacific Ocean near Samoa, watching and listening as the West Mata Volcano erupted in several ways. Putting video and audio together let researchers learn the sounds made by slow lava bursting and the different noises made by hundreds of gas bubbles.[6][7]

See also

References

  1. ^ a b Martin R. Speight, Peter A. Henderson, "Marine Ecology: Concepts and Applications", John Wiley & Sons, 2013. ISBN 978-1-4051-2699-1.
  2. ^ Michael E. Q. Pilson, "An Introduction to the Chemistry of the Sea", 2nd edition. Cambridge University Press, 2013.
  3. ^ Umino, Susumu; Lipman, Peter W.; Obata, Sumie (2000-06-01). "Subaqueous lava flow lobes, observed on ROV KAIKO dives off Hawaii". Geology. 28 (6): 503–506. doi:10.1130/0091-7613(2000)282.0.CO;2. ISSN 0091-7613.
  4. ^ Nybakken, James W. and Bertness, Mark D., 2005. Marine Biology: An Ecological Approach. Sixth Edition. Benjamin Cummings, San Francisco
  5. ^ "Scientists Discover and Image Explosive Deep-Ocean Volcano". NOAA. 2009-12-17. Retrieved 2009-12-19.
  6. ^ Scientificamerican.com 2015-04-22 Undersea Volcano Explodes as Scientists Watch
  7. ^ Dziak, R. P.; Bohnenstiehl, D. R.; Baker, E. T; Matsumoto, H.; Caplan-Auerbach, J.; Embley, R. W.; Merle, S. G.; Walker, S. L.; Lau, T.-K.; Chadwick, W. W. (2015). "Long-term explosive degassing and debris flow activity at West Mata submarine volcano" (PDF). Geophysical Research Letters. 42 (5): 1480–1487. doi:10.1002/2014GL062603.

External links

1955 Hawaiian submarine eruption

The 1955 Hawaiian submarine eruption was a submarine eruption that occurred 90 km (56 mi) northeast of Necker Island on August 20, 1955. Steaming water, water discoloration and an eruption column took place during the eruption. A possible pumice raft was also witnessed. The eruption originated about 4 km (2.5 mi) below sea level from an unnamed submarine volcano. The eruption produced a column of smoke several meters high. It is probably the westernmost historical eruption within the Hawaiian Islands. Another but less certain submarine eruption may have occurred 60 km (37 mi) northwest of Oahu on May 22, 1956.

Axial

Axial may refer to:

one of the anatomical directions describing relationships in an animal body

Axial Seamount and submarine volcano off Oregon, USA

Axial, Colorado, a ghost town

In geometry:a geometric term of location

an axis of rotationthe Axial age in China, India, etc.

a type of modal frame, in music

axial-flow, a type of fan

Bowie Seamount

Bowie Seamount is a large submarine volcano in the northeastern Pacific Ocean, located 180 km (110 mi) west of Haida Gwaii, British Columbia, Canada.

The seamount is also known as Bowie Bank. In the Russian language, Bowie is called Гора Бауи (Gora Baui), which literally means Mount Bowie. In Haida language it is called SG̱aan Ḵinghlas, meaning Supernatural One Looking Outward. It is named after William Bowie of the U.S. Coast and Geodetic Survey.The volcano has a flat-topped summit rising about 3,000 m (10,000 ft) above the seabed, to 24 m (79 ft) below sea level. The seamount lies at the southern end of a long underwater volcanic mountain range called the Pratt-Welker or Kodiak-Bowie Seamount chain, stretching from the Aleutian Trench in the north almost to Haida Gwaii in the south.Bowie Seamount lies on the Pacific Plate, a large segment of the Earth's surface which moves in a northwestern direction under the Pacific Ocean. It is adjacent to two other submarine volcanoes; Hodgkins Seamount on its northern flank and Graham Seamount on its eastern flank.

Curacoa volcano

Curacoa is a submarine volcano located south of the Curacoa Reef in northern Tonga. Eruptions were observed in 1973 and 1979 from two separate vents. The 1973 eruption produced a large raft of dacitic pumice, and had a volcanic explosivity index (VEI) of 3.

Dom João de Castro Bank

Dom João de Castro Bank (Portuguese: Banco de D. João de Castro) is a large submarine volcano located in the central north Atlantic Ocean, between the islands of São Miguel and Terceira in the archipelago of the Azores.

Emperor of China (volcano)

Emperor of China is a submarine volcano in the western part of the Banda Sea, Indonesia. This volcano is part of a chain with Nieuwerkerk volcano, known scientifically as the Emperor of China–Nieuwkerk (NEC) ridge, the depth of which is ranging from 3,100–2,700 metres (10,170–8,858 ft).The NEC ridge is lying on Damar Basin, a sea basin of which has 1–2 km Pliocene–Quaternary sediment thickness and is topologically flat. Damar Basin is located in Banda Sea, which is bounded by East Sunda and Banda volcanic arcs within the area of three major plates, namely Eurasian, Pacific and Indo-Australian plates; all of the three plates have been actively converging since Mesozoic times.

The two submarine volcanoes (the Emperor of China and Nieuwerkerk) are located at both ends of the NEC ridge, and they were active. Based on the geological and geochemical study, Emperor of China, Nieuwekerk, another ridge in the Banda Sea called Lucipara, and the Wetar segment were a single volcanic arc around 8–7 Ma ago. The volcanic activity was related to the subduction of the Indian oceanic lithosphere beneath the Australia continental block. From a survey conducted in 1979, both Emperor of China and Nieuwerkerk have been defined as extinct based on their structural settings and their age, which is stated that the volcanic activity was estimated stopped after 7 Ma ago. The end of magmatic activity in the NEC ridge at 3 Ma is thought of as the result from the collision of Timor and the Wetar segment of the Sunda Arc.

Kick 'em Jenny

Kick 'em Jenny (also: Kick-'em-Jenny or Mt. Kick-'Em-Jenny) is an active submarine volcano or seamount on the Caribbean Sea floor, located 8 km (5 mi) north of the island of Grenada and about 8 km (5 mi) west of Ronde Island in the Grenadines. Kick-'em-Jenny rises 1,300 m (4,265 ft) above the sea floor on the steep inner western slope of the Lesser Antilles ridge. The South American tectonic plate is subducting the Caribbean tectonic plate to the east of this ridge and under the Lesser Antilles island arc.

Kolumbo

Kolumbo is an active submarine volcano in the Aegean Sea, about 8 km northeast of Cape Kolumbo, Santorini island. The largest of a line of about twenty submarine volcanic cones extending to the northeast from Santorini, it is about 3 km in diameter with a crater 1.5 km across. It was "discovered" when it breached the sea surface in 1649-50, but its explosion was not to be compared to the well-known Thera explosion and caldera collapse, currently dated ca. 1630 BCE, with its devastating consequences for Minoan civilization. The Smithsonian Institution's Global Volcanism Program treats it as part of the Santorini volcano.The 1650 explosion, which occurred when the accumulating cone reached the surface, sent pyroclastic flows across the sea surface to the shores and slopes of Santorini, where about seventy people and many animals died. A small ring of white pumice that formed was rapidly eroded away by wave action. The volcano collapsed into its caldera, triggering a tsunami that caused damage on nearby islands up to 150 km distant. The highest parts of the crater rim are now about 10 m below sea level.

In 2006, sea floor pyroclastic deposits from the two Aegean explosions were explored, sampled and mapped by an expedition by NOAA Ocean Explorer, equipped with ROV robotics.

The crater floor, averaging about 505 m below the sea surface, is marked in its northeast area by a field of hydrothermal vents and covered by a thick bacterial community, the 2006 NOAA expedition discovered. Superheated (measured as hot as 224 °C) metal-enriched water issuing from the vents has built chimneys of polymetallic sulfide/sulfates to a maximum height of 4 m, apparently accumulated since the 1650 event.

The 2006 expedition initiated new seismic air-gun techniques in order to determine the volume and distribution of the submarine volcanic deposit of pumice and ash on the sea floor around Santorini, which has been studied extensively since 1975. Revised, more accurate estimates of the total dense rock equivalent volume of the Minoan event(s), consisting of pyroclastic sea floor deposits, distal ash fallout and ignimbrites on the island of Santorini, is likely about 60 km³, a greatly increased estimate, comparable to the largest historic explosion, Mount Tambora 1815; the increased estimate affects the size of the ensuing tsunami as it has been widely modeled.

Lōʻihi Seamount

Lōihi Seamount (also known as Lōʻihi) is an active submarine volcano about 35 km (22 mi) off the southeast coast of the island of Hawaii. The top of the seamount is about 975 m (3,000 ft) below sea level. This seamount is on the flank of Mauna Loa, the largest shield volcano on Earth. Lōihi, 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 Hawaii hotspot, and as the youngest volcano in the chain, Lōihi is the only Hawaiian volcano in the deep submarine preshield stage of development.

Lōihi 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. A diverse microbial community resides around Lōihi's many hydrothermal vents.

In the summer of 1996, a swarm of 4,070 earthquakes was recorded at Lōʻihi. At the time this was the most energetic earthquake swarm in Hawaii 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 United States Geological Survey (USGS). The Hawaii Undersea Geological Observatory (HUGO) provided real-time data on Lōʻihi between 1997 and 1998. Lōʻihi's last known eruption was in 1996, before the earthquake swarm of that summer.

Moai (seamount)

The Moai Seamount is a submarine volcano, the second most westerly in the Easter Seamount Chain or Sala y Gómez ridge. It is east of Pukao seamount and west of Easter Island. It rises over 2,500 metres from the ocean floor to within a few hundred metres of the sea surface. The Moai seamount is fairly young, having developed in the last few hundred thousand years as the Nazca Plate floats over the Easter hotspot.

The Moai seamount was named after the moai statues of neighbouring Easter Island.

Nieuwerkerk (volcano)

Nieuwerkerk is a submarine volcano in the Banda Sea, Indonesia. Along with the Emperor of China submarine volcano, the two twin forms a ridge (NEC ridge) on the seabed. The NEC ridge were dredged at depths ranging from 3,100–2,700 metres (10,170–8,858 ft).

Protector Shoal

Protector Shoal is a submarine volcano, also called seamount, which rises gently from an ocean depth of 3,900 feet (1,200 m) to about 55 metres (180 ft) below sea level approximately 31 miles (50 km) NW of Zavodovski Island in the South Sandwich Islands chain. The last eruption occurred during March 1962. Protector Shoal is the only volcano in the arc that has erupted rhyolite pumice.

Pukao (seamount)

The Pukao Seamount is a submarine volcano, the most westerly in the Easter Seamount Chain or Sala y Gómez ridge. To the east are Moai (seamount) and then Easter Island. It rises over 2,500 metres from the ocean floor to within a few hundred metres of the sea surface. The Pukao Seamount is fairly young, and believed to have developed in the last few hundred thousand years as the Nazca Plate floats over the Easter hotspot.

Suiyo Seamount

Suiyo Seamount is a seamount (submarine volcano) off the eastern coast of Japan, directly south of Torishima and Sofugan volcano at the southern tip of the Izu Islands. The volcano is one of the Shichiyo Seamounts, a small group of submarine volcanoes named after different days of the week ("Suiyo" means "Wednesday" in Japanese).Suiyo consists of a basaltic to dacitic submarine caldera and lava dome, and rises about 1,400 m (4,590 ft) from its base on the sea floor to within 1,418 m (4,652 ft) of the surface. Suiyo has a prominent summit caldera, 1.5 km (0.9 mi) wide and 500 m (1,640 ft) deep.The volcano's excised (weathered) structure suggests that it is of older age then some of the other volcanoes in the group. Suiyo is covered by a thick sediment cap, a feature that collects over a long span of inactivity, and fault patterns and valleys have been observed on its flanks.Suiyo Seamount is associated with a magnetic anomaly: ocean-floor surveys of it and the surrounding area found that a large negative rock body existed to the east of the seamount, while positive bodies existed to the northwest and south. The reasons for this complex anomaly, which also exists in several other nearby seamounts, is unknown, but is suggested to be the result of interactions between different magnetic fields of different ages.A burst of hydrothermal activity was observed in July 1991, raising water temperatures at the vent to 290 °C (550 °F); following the event, the volcano, until then thought extinct, was reclassified as active by the Japan Meteorological Agency. A bathymetric survey of the volcano found sulfur-oxidizing microbes to be predominant, and concluded that Suiyo Seamount was a natural "incubator" for this bacterial type.

Tjörnes

Tjörnes is a peninsula situated at the northeast of Iceland, between the fjords of Öxarfjörður and Skjálfandi. Tjörnes is known for its particularly dense population of Rock Ptarmigan and the rich fossil record of Miocene - Pliocene age.

Underwater volcano

Underwater volcano may refer to:

Subaqueous volcano, a volcano that forms under a lake

Submarine volcano, a volcano that forms under an ocean

Unnamed volcano (Ibugos)

Unnamed volcano (Ibugos), is a submarine volcano near the island Ibugos in the Philippines.

West Mata

West Mata is a submarine volcano at 1,100 meters depth 200 kilometres (120 mi) southwest of the Samoas. Its eruptions are currently the deepest observed.

Yersey

Yersey is a submarine volcano in Indonesia. It was listed as an active volcano in the old sea charts at the location in the southern of Banda Basin. During the 1929 survey, the volcano was spotted at the depth of 3,800 m along the ridge that stretches from Batu Tara until Gunungapi Wetar.

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