Huge active underwater volcano discovered near Indonesia. Underwater eruptions and underwater volcanoes…

underwater volcanism

Rocks of igneous origin - erupted lavas, eruption products, magmatic bodies frozen at a depth - make up more than 2/3 of the volume of the earth's crust. According to seismic studies, the so-called "second layer" of the oceanic crust underlying the sediments is almost entirely composed of underwater basaltic lavas.

Thus, volcanoes serve as the main suppliers of matter from the bowels of the Earth to its surface.

Types of underwater volcanism

At present, it is customary to distinguish four main types of modern volcanism of the ocean floor and its framing:

- oceanic rift volcanism, characteristic of mid-ocean ridges,

- volcanism of island arcs and active continental margins,

- volcanism of inland ocean islands,

- volcanism of marginal seas.

Areas of terrestrial and underwater volcanism spatially coincide with seismically active areas and areas of increased heat flow from the Earth's interior. In other words, volcanoes are characteristic of the tectonically most mobile, mechanically weakened zones of the earth's crust.

Oceanic rift volcanism.

Rift volcanism of the oceans is characteristic of rift zones of mid-ocean ridges and is localized at the boundary between moving plates.

Rift zones are dominated by lava eruptions fissure type . It is they who form long chains of volcanic domes 200-300 m high and 2-4 km long with a width of about 0.5 km.

The products of modern underwater volcanic activity in rift zones are mainly represented by basalts homogeneous in chemical composition.

As a result of effusive (outpouring) oceanic rift volcanism, second layer of oceanic crust with an average thickness of about 1.5 km.

Layer 1: formed at a distance from the ROC axis due to slow sedimentation

Layer 2: is formed directly in the rift zone of the MOR due to the intrusion (2С) and outpouring (2А-В) of basalt melt during crustal spreading

Sublayer 3A: is formed under the axial zone of the ROC due to

crystallization of basalt melt along the walls

magma chamber

Sublayer 3B: formed at a small distance from the ROC axis for

account of hydrothermal circulation and serpentinization of part

upper mantle

Volcanism of intra-oceanic islands.

Virtually all islands and seamounts in the interior of the oceans are either active volcanoes or have been in the past. They usually form linear chains of islands and seamounts. Moreover, active volcanism manifests itself at one end of such a chain, and with distance from the active center, the age of volcanoes increases. For example, Hawaiian Islands together with the Imperial underwater ridge form a single chain. This chain stretches from the island of Hawaii to the zone where the Kurile-Kamchatka and Aleutian island arcs converge. Active volcanoes in this chain are found only on the island of Hawaii and in the east of the island of Maui. To the northwest of the island of Hawaii, the age of volcanic rocks gradually increases, reaching 40-43 million years in the place where the Hawaiian Islands and the Imperial underwater ridge converge. If you move north along the Imperial Range, their age will increase even more. The volcanic rocks recovered by a borehole in the northern part of the Imperial Range are older than 72 million years.

The increase in the age of the volcanic rocks of the Hawaiian Ridge was the starting point for the development of the "hot spots" hypothesis. This hypothesis was proposed by J. Wilson and substantiated by W. Morgan. According to Morgan, "hot spots" are fixed and are rounded areas. In these zones mantle jets rising from the mantle reach the Earth's surface. Active underwater volcanoes arise above such mantle jets.

The buildup of volcanoes leads to the formation of volcanic islands. These islands, like on a conveyor belt, move along with the plate lithosphere, moving away from the rift zone. As a result of such movement, the connection between the island and the fixed mantle jet is interrupted, and the volcano ceases its active existence. At the same time, a new volcano grows again above the mantle jet. Thus, the mantle jet, as it were, burns through the moving lithospheric plate, leaving a seam on it in the form of a volcanic ridge, or rather a chain of volcanoes. This creates the effect of migration of volcanism in the direction opposite to the movement of the plate. Bends in the chains of volcanoes have arisen as a result of a change in the direction in which the plate moves.

"Hot spots" can also be located on the border between the sliding plates. In this case, they represent areas of increased volcanic activity within rift zones. Iceland and the Azores are examples of such hotspots. Volcanic ridges formed as a result of the activity of such volcanoes extend in both directions from the rift zone.

In the development of individual volcanoes of the "hot spots" type, one can single out the main period and the period of rejuvenation. The period of rejuvenation usually occurs after a break of several million years.

Island formation. At the first stage, the volcano rises from a depth of 4-5 km and reaches the surface of the ocean. Calm eruptions of lavas are characteristic of this stage. These lavas have a low viscosity and therefore spread over large area, forming gently sloping volcanic structures - shield volcanoes.

When the volcano reaches the surface of the ocean, calm lava outpourings are replaced by volcanic explosions. These volcanic explosions are called hydromagmatic. But as soon as the volcano rises above the ocean level and the erupting melt no longer comes into direct contact with water, the eruptions become calm again. There is an outpouring of lavas of low viscosity. This type of eruptions is called Hawaiian.

The period of rejuvenation is characterized by the outpouring of lava through small side cones on the slopes of shield volcanoes. In the future, the volcanic islands are destroyed and, sinking, turn into atolls.

In the southern part Pacific Ocean there is a whole belt of island and underwater volcanoes of the "hot spots" type. At least 10 volcanoes in this belt were active during the Pleistocene and Holocene. The belt consists of several closely spaced chains of volcanoes. This volcanic belt is located perpendicular to the rift zone of the East Pacific Rise and is confined to the area where the expansion rate in both directions from the rift zone is maximum. In such areas, convective currents can occur, which is probably the reason for the formation of this belt of “hot spots”.

Volcanism of island arcs and active continental margins.

These volcanoes are the most widely known, as they make up the vast majority of volcanoes that rise above sea level. In addition, their eruptions are often catastrophic. Most active volcanoes known on Earth (according to A. Ritman's calculations, about 62%) are located on the periphery of the Pacific Ocean. They form the so-called Pacific "fire" ring.

From the point of view of supporters of the theory of plate tectonics, island arc volcanoes are located on the edge of a plate advancing on the continent. The centers of melting of the magma that feeds the volcanoes are concentrated in the layer where the earthquake sources are located (the seismic focal layer) and, probably, in the upper mantle above the seismic focal layer.

Some island arc volcanoes went through an underwater stage in their early development. An example of modern underwater volcanoes is the Mariana arc.

Both underwater and terrestrial volcanoes of island arcs are characterized by volcanic igneous rocks.

Terrestrial volcanoes of island arcs are characterized by both calm eruptions of the Hawaiian type and catastrophic explosions, as a result of which a huge amount of volcanic material is ejected.

Moreover, the volume of volcanic material delivered to the surface by island arc volcanoes is much lower than that of mid-ocean ridge volcanoes.

Volcanism of marginal seas

It has been poorly studied, since information on the manifestation of volcanic activity is extremely scarce. Shallow-water volcanoes are located on the crust of the continental type.

Paleomagnetism

Lamont scale

Hydrothermal circulation in the oceanic crust, serpentinization of the upper mantle (sublayer 3B), "black smokers"

In the light of recent events in Iceland, the topic of volcanoes has become extremely popular and, of course, keeping up with the times, we decided to make a selection about underwater volcanoes. After all, terrestrial, after becoming famous volcano Eyyafyatlayokudl, you will not surprise anyone.

Coast of Tonga


Thirty kilometers from Falcon Island is an underwater volcano called Hunga Tonga-Hunga Haʻapai or Hunga-Tonga for short. The volcano is located 100 kilometers from an area with high seismological activity. It should be noted that relatively recently, in March 2009, the volcano began throwing pillars of smoke and ash thousands of feet above the ocean.

Hawaii


Loihi is an underwater active volcano located 35 kilometers southeast of the island of Hawaii on the slope of Mauna Loa, the largest shield volcano in the world. Loihi is one of the youngest volcanoes Hawaiian ridge. It was first discovered in 1970, but began to act later - the first activity was noted in 1996.

Iceland


They did not expect? Another young volcano formed in 1973 as a result of an eruption on the outskirts of the city of Heimaey. The Eldfell eruption was both for scientists and for local residents complete surprise. Emissions from the volcano continued until July 1974, after which Eldfell lost activity. New eruptions, according to experts, are unlikely. The height of Eldfell is about 200 meters.

Vanuatu

It's about the volcano Yasur (Yasur). This is very old volcano, which scientists believe formed about a million years ago, but was discovered only in 1774, when the first documented eruption occurred. Yasur is also considered one of the most active volcanoes. Last eruption was not so long ago, in 2008, and in 2010 signs were found that the volcano was becoming active again. The volcano is located southeast of high volcano Tukosmera, but last time erupted in the Pleistocene.

Sumatra


In Sumatra, which is located west of Indonesia, there are enough a large number of volcanoes - 90, fifteen of which are active. The undersea earthquake in Sumatra is the main cause of the 2004 Asian tsunami.

And by the way, one more interesting fact, regarding Sumatra: about 73 thousand years ago, a giant explosion of the Toba volcano occurred on this island. As a result, a funnel with a diameter of about 100 km was formed at the site of the explosion, and 800 cubic kilometers of dust and ash fell into the atmosphere. This event had, according to scientists, dramatic consequences, since it provoked an 1800-year ice age.

Based on Wikipedia, the free encyclopedia

Life in surface waters ocean, on which the volume of greenhouse gases absorbed by the ocean depends, is supported by the activity of underwater volcanoes.

This happens because underwater volcanoes supply phytoplankton with iron compounds necessary for photosynthesis. This is stated in an article by American scientists in the journal Nature Geoscience. Iron particles, a necessary element for most food chains, are very rare in surface ocean waters.

Previously, it was believed that they get there mainly with the waters of rivers and streams. Scientists from the University of Minnesota have shown that most of iron, necessary for phytoplankton, can come to the surface from the bottom. “Deep volcanoes at the bottom of the ocean supply its waters with a large amount of iron, but whether this iron gets into the upper layers of the ocean and whether it is absorbed by living organisms depends on the chemical form of iron. At the bottom, we managed to find iron in a completely unexpected form,” said the head of the study, Professor Brandi Tonera.

Previously, scientists believed that most of the iron ejected by underwater volcanoes settles to the bottom in inorganic form.

With the help of remote control deep-sea vehicles the researchers collected particle samples from various volcanically active regions of the Pacific Ocean. Volcanoes create so-called hydrothermal jets - the water in them reaches a temperature of several hundred degrees, but due to the enormous pressure it does not turn into steam. These hydrothermal jets contain a large amount of dissolved substances, including iron ions.

These ions, as the researchers were able to show, further react with organic compounds dissolved in water, form small particles of submicron size, and are carried away by underwater currents.

Unlike iron, which enters the ocean from rivers and streams in a more oxidized form of Fe, hydrothermal plumes create large quantity more suitable for the assimilation by living organisms of ferrous iron Fe.

The authors of the article hope that their discovery will lead to a revision of existing opinions about the cycle of iron and carbon in the ocean. It is likely that such a revision will affect experimental work on the "fertilization" of the ocean with iron compounds in order to combat global warming.

underwater volcanoes

Underwater volcanoes are located at the bottom of the ocean and are much larger and more energetic than terrestrial ones. They are the main source of tsunamis on Earth.

On our planet, volcanoes located under water produce ¾ of all magma ejected from the bowels of the planet per year. Majority active volcanoes located at the junction of tectonic plates in the so-called oceanic ridges. These ridges pass in their mass deep under water, so most of the eruptions are not visible to humans. Yes, and it is often not possible to notice the eruption that has occurred with the help of acoustic equipment. This is related to the fact that great depths, when magma is ejected into cold water, it immediately cools down, turning into volcanic glass, so it does not boil, so it is impossible to hear it.

Underwater volcanoes grow in height. As they erupt, they are overgrown with volcanic mass, which does not scatter far, as on the surface of the earth. Over time, the volcano goes out, having used up the reserves of its magma. If during its life the volcano reaches the surface of the water, then it gives birth to a volcanic island. and disappears over time. Scientists estimate that most of the 30,000 known seamounts are extinct volcanoes.

Despite the destructive power of volcanoes, it is reliably known that the eruption releases organic compounds into the water, which are necessary for the development of phytoplankton. This, in turn, supports the diversity of the entire animal world.

Due to the fact that volcanoes give life to ocean flora, it has been suggested that the greater activity of volcanoes could give impetus to a large increase in the population of marine animals and plants. With the death and decomposition of such an amount of live mass, all the oxygen dissolved in water was absorbed, which led to the extinction of 70% of animal species from suffocation.

This theory has many controversial points: Firstly, a uniform increase in animal weight will not lead to an excess of decomposing animals, because. they will be devoured by scavengers, who live in abundance at the bottom. Secondly, the found evidence of volcanic activity only confirms that it was, but does not prove that there was so much of it. how much is needed for such a mass extinction.

Another young volcano formed in 1973 as a result of an eruption on the outskirts of the city of Heimaey. The eruption of Eldfetl was a complete surprise for both scientists and local residents. Emissions from the volcano continued until July 1974, after which Eldfell lost activity. New eruptions, according to experts, are unlikely. The height of Eldfell is about 200 meters.

It's about the Yasur volcano. This is a very old volcano, which scientists believe formed about a million years ago, but was discovered only in 1774, when the first documented eruption occurred. Yasur is also considered one of the most active volcanoes. The last eruption was not so long ago, in 2008, and in 2010 there were signs that the volcano was becoming active again. The volcano is located southeast of the higher volcano Tukosmera, which last erupted in the Pleistocene.

In Sumatra, which is located west of Indonesia, there is a fairly large number of volcanoes - 90, fifteen of which are active. The undersea earthquake in Sumatra is the main cause of the 2004 Asian tsunami.

And, by the way, one more interesting fact about Sumatra: about 73 thousand years ago, a giant explosion of the Toba volcano occurred on this island. As a result, a funnel with a diameter of about 100 km was formed at the site of the explosion, and 800 cubic kilometers of dust and ash fell into the atmosphere. This event had, according to scientists, dramatic consequences, since it provoked an 1800-year ice age.

underwater volcano - A type of volcano. These volcanoes are located at the bottom of the ocean.

Most modern volcanoes are located within three main volcanic belts: the Pacific. Mediterranean-Indonesian and Atlantic. As evidenced by the results of studying the geological past of our planet, submarine volcanoes in terms of their scale and volume of ejecta products coming from the bowels of the Earth significantly exceed volcanoes on land. If on land annually from 20-30 volcanic eruptions an average of up to one and a half cubic kilometers of molten magma per year comes out, then during the same time 12-15 times more material erupts from underwater volcanoes.

This happens because underwater volcanoes supply phytoplankton with iron compounds. necessary for photosynthesis. Iron particles, a necessary element for most food chains, are very rare in surface ocean waters. Previously, it was believed that they get there mainly with the waters of rivers and streams. Scientists from the University of Minnesota have proven that most of the iron needed for phytoplankton. can come to the surface from the bottom.

Previously, scientists believed that most of the iron ejected by underwater volcanoes settles to the bottom in inorganic form. Using remotely controlled deep-sea vehicles, the researchers collected particle samples from various volcanically active regions of the Pacific Ocean. Volcanoes create so-called hydrothermal jets - the water in them reaches a temperature of several hundred degrees, but due to the enormous pressure it does not turn into steam. These hydrothermal jets contain a large amount of dissolved substances, including iron ions.

These ions, as the researchers were able to show, further react with organic compounds. dissolved in water, form small particles of submicron size, and are carried away by underwater currents.

Unlike iron, which is more suitable for assimilation by living organisms, ferrous iron Fe. The authors of the article hope that their discovery will lead to a revision of existing opinions about the cycle of iron and carbon in the ocean. It is likely that such a revision will affect experimental work on the "fertilization" of the ocean with iron compounds in order to combat global warming.

Underwater volcanic eruptions

If a reservoir is located above the volcanic chamber, during the eruption, the pyroclastic material is saturated with water and spreads around the chamber. Deposits of this type, first described in the Philippines, were formed as a result of the eruption in 1968 of the Taal volcano. located at the bottom of the lake; they are often represented by thin, wavy layers of pumice. As a result of the activity of underwater volcanoes, islands can form, for example, Reunion - volcanic island in the Indian Ocean.

It is generally accepted that all major geographical discoveries on Earth have already been made. But in fact, more than half of the surface of our planet remains completely unexplored, primarily the bottom of the ocean. This confirms the discovery made by the last expedition.

A team of Americans and Indonesians on a research vessel studied the anomaly in the sea between Indonesia and the Philippines. The anomaly was identified several years after the analysis satellite imagery Earth.

Only a satellite could notice this, because the depth of the sea in this area is 5-6 kilometers, but from the pictures it immediately became clear that a mountain of a regular conical shape rises above a relatively flat bottom, no less than 1855 meters high.

Alone standing mountain- This underwater volcano. To test this assumption, the Argus deep-sea platform was lowered from the ship, and a small Hercules self-propelled vehicle with a searchlight and a video camera was launched from it.

The frames obtained from a depth of 1855 meters show a pronounced volcanic activity: powerful hot jets carry out a transparent liquid in some places, and white or black "smoke" in others. Yellow and black deposits of molten sulfur are visible near them. And around, in the complete absence sunlight, life is in full swing: a forest of worms sways, shrimp and crustaceans scurry about. All of them receive nutrients and energy from the bowels of the earth.

On land, volcanologists have identified almost all volcanoes that have ever erupted, but in underwater world- at best, every fifth. So the era geographical discoveries continues.

Sources: www.sunhome.ru, www.inokean.ru, relaxic.net, dic.academic.ru, zemlyanin.info

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underwater volcano- A type of volcano. These volcanoes are located at the bottom of the ocean.

Most modern volcanoes are located within the three main volcanic belts: Pacific, Mediterranean-Indonesian and Atlantic. As evidenced by the results of studying the geological past of our planet, submarine volcanoes in terms of their scale and volume of ejecta products coming from the bowels of the Earth significantly exceed volcanoes on land. If on land annually from 20-30 volcanic eruptions an average of up to one and a half cubic kilometers of molten magma per year enters, then during the same time 12-15 times more material erupts from underwater volcanoes.

Life in the near-surface waters of the ocean, on which the volume of greenhouse gases absorbed by the ocean depends, is supported by the activity of underwater volcanoes.

When we hear about volcanoes, we immediately imagine fire-breathing mountains spewing clouds of ash, thousands of volcanic bombs and hot lava flows. Such pictures are typical for volcanoes located on land, but not everyone knows that at the bottom of the World Ocean there are much more active and extinct volcanoes than on all the earth's continents.

Underwater volcano West Mata in the Pacific Ocean

Newborn Islands

It would seem that in our time geographical maps no longer need any changes, all continents and even the most tiny islands, using aerial photography and satellite images their contours and coordinates have been specified.

However, the Earth is not a dead cosmic body, it continues to live actively, and new islands that appear on the surface of the ocean from time to time are proof of this. Their birth is associated with underwater volcanic activity, which is especially intense in the Pacific Ocean.

On this moment about two hundred cases of underwater volcano eruptions were recorded, which ended with the appearance of new islands on the surface of the ocean. True, not all "newborns" managed to resist the onslaught of waves, storms and undercurrents, only a quarter of the emerging islands "survived" and eventually ended up on geographical maps. Here are just a few examples of islands that have risen from the depths of the sea.

In 1796, in the Aleutian archipelago, an underwater volcano during the eruption increased its height so much that it rose above the surface of the ocean. Within a few years, the area of ​​the volcanic island reached 30 square meters. kilometers and it was named John the Theologian Island (Bogoslovsky Island). The island is reported to have periodically appeared and disappeared. The last time its "revival" was recorded in 1910.

In 1883, next to this island, another volcanic island rose from the water and connected with it with an isthmus. The process of the birth of islands in this place did not end there, a few years later three more volcanic islands rose from the water to a height of up to three hundred meters.

Island of John the Evangelist. Navarino district Bering Sea. November 1976

In 1974, underwater volcanism helped Japan expand its territory a little. That year, at a distance of 1000 km from Tokyo, a volcanic island with an area of ​​205,000 square meters rose from the water. meters, called Nishinoshima. The island belongs to the Ogawasara island chain. Since then, it has been constantly increasing its size.

Nishinoshima in 1978

After some time, after the assurances of volcanologists and oceanologists in its stability, it was included in the territory of Japan. As of November 20, 2015, the length of the island from west to east is 1850 meters, and from south to north - 1900 meters. highest point The island is located at an altitude of about 100 meters above sea level.

In 2015 in the South Pacific appeared new island- it happened due to the eruption of an underwater volcano Hunga Haapai. The island is located at a distance of 45 kilometers from Nuku'alofa, the capital of the Kingdom of Tonga.

The length of the island is 1.8 kilometers, the width is 1.2 kilometers, but scientists warn of its instability: the island can crumble into pieces and sink to the bottom of the sea. It consists mainly of volcanic slag: dark rock, where crystals are sometimes found.

The eruption of an underwater volcano near the state of Tonga, clouds of steam, ash and smoke reach a height of 100 meters (March 18, 2009).

Before the eruption of the Hunga Ha'apai volcano in 2015 and after

asphalt volcanoes

Back in the 20th century, scientists found that there are much more underwater volcanoes on our planet than those located on land. Under water, they counted about 32 thousand volcanoes, and on land only 1.5 thousand. The Pacific Ocean became a real record holder in the number of underwater volcanoes, this became clear when summing up the results of the International Geophysical Year.

According to a number of scientists, this was one of the most amazing discoveries of the last century. It also turned out that the activity of underwater volcanoes is much higher than that of surface volcanoes. Almost all the mountains at the bottom of the oceans turned out to be volcanoes, active or already extinct. Scientists managed to discover a system that combines land volcanoes with their underwater counterparts, it was called the Pacific Ring of Fire.

Pacific volcanic ring of fire

In addition to the very common and quite ordinary underwater volcanoes, scientists, 10 miles off the coast of California, managed to discover a number of unique asphalt volcanoes that had no analogues to date. These volcanoes are about 40 thousand years old, the largest of them is at a depth of 220 meters; no wonder it was only recently discovered.

The height of the volcanoes is slightly higher than a six-story building, and their base can exceed the area of ​​a football field. They consist entirely of asphalt and, according to scientists, were formed as a result of a series of large portions of hydrocarbons entering the bottom of the Pacific Ocean.

The oil spilled to the bottom of the ocean solidified, forming cones of bitumen. To study the unique natural formations, scientists first used the research submarine Alvin, plunging on it directly to the volcanoes.

Asphalt volcano at the bottom of the Gulf of Mexico

Then, using a remote-controlled underwater vehicle with a manipulator, samples of the volcanic rock were taken. It turned out to be very fragile and easily crushed to the state of "thick oil", which can be used to generate energy.

Scientists believe that at the same time as oil on the ocean floor, there was also an abundant release of methane, a greenhouse gas. According to researchers from the University of Santa Barbara, it was the intense release of methane in these volcanoes that could be one of the reasons for the start of the Ice Age.