Volcanoes underwater eruptions. underwater volcano

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. IN 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.

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. According to the results of studying the geological past of our planet, underwater volcanoes in terms of scale and volume of ejecta products coming from the bowels of the Earth, they 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.

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. In total, there are about 32 thousand underwater volcanoes.

At the very big volcano The solar system - the Martian Olympus - has a competitor. They found it not on other planets, but on Earth under the water column - at the bottom of the Pacific Ocean. The results of the study by American geophysicists were published in an article in the journal Nature Geoscience.

A volcano the size of Britain has been discovered in the northwestern Pacific Ocean, on a massif Tamo, where several tectonic plates. The results of drilling of the bottom in this area showed that it consists entirely of lava deposits, but so far it has not been clear whether Tamo is a single volcano or there were several eruption points. It turned out that the lava flows came from one point, which means that there is a single central vent.

"Before that, we were not sure that we were dealing with a single volcano capable of growing to such a size. Now we are sure," said William Sager, lead author of the study. "Thus, the Tamo massif is the largest shield volcano ever discovered on Earth," he added.

Tamo, which belongs to the class of shield volcanoes, very large in area and with gentle slopes, reaches 4 km in height, and its diameter is approximately 625 kilometers. For comparison: the diameter of the largest Mauna loa volcano does not even reach ten kilometers. Tamo formed about 145 million years ago and has not erupted for 140 million years.

The discovery will allow scientists to learn more about how much magma can accumulate underground and slosh to the surface. Experts also noted that Tamo's shape is different from other underwater volcanoes, and expressed the hope that its study will give them a clue to understanding how such massive volcanic formations are formed.

Scientists have discovered 12 previously unknown underwater volcanoes in Antarctica. The authors spoke about their discovery at the 11th International Symposium on Antarctic Studies. Briefly, the essence of the report is given in a press release on the website of the British Antarctic Survey.

The researchers studied the bottom topography in the area of ​​the South Sandwich Islands from 2007 to 2010. With the help of sonars, they were able to detect new volcanoes - the height of some of them reaches three kilometers. Seven of the found volcanoes are active and visible above the surface of the water - they look like a chain of islands. In addition, scientists discovered a funnel with a diameter of about five kilometers, which remained after the destruction of one of the volcanoes.

The authors note that at the moment, specialists know very little about the features of underwater volcanoes at high latitudes and their impact on the biology of these territories. active volcanoes heat the water around them and can thus create favorable conditions for the habitat of many living organisms.

volcanic island- an island formed as a result of volcanic activity at the bottom of the sea.

In practice, a series of volcanic islands usually arise, which are the upper part of the volcanic ridge, located with a certain pattern ( Hawaiian Islands, Canary Islands, Kurile Islands etc.)

The island is the top of an underwater volcano, raised above the surface of the ocean. The formation of the island occurs in several phases.

Darwin suggested that growth coral islands(atolls) occurs in the process of gradual subsidence of volcanic islands. He noted that atolls are usually formed by fouling of a volcanic island. coral reef forming an annular belt.

Iceland is the largest volcanic island. The second largest island of Hawaii ( Big Island). In third place is the island of Bali. In Russia, the largest volcanic island is Iturup. The largest island crater - 4.5 km in diameter - has Kilauea in the Hawaiian archipelago.

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Volcanism on earth and its geographical consequences

Volcanoes are a geological formation above channels and cracks in the earth's crust through which lava erupts hot gases of ash and water to the surface.

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Concerning volcanic activity under the thickness ocean waters, then it refers to fairly frequent natural phenomena. As you know, some volcanoes are located on seabed -these are underwater volcanoes. Some now "land" volcanoes also began their activity under water, for example, the Sicilian volcano Etna, the famous Vesuvius and many others.

The consequences of the eruption in the ocean of the Mejin-sho volcano in 1952 turned out to be tragic. Its first eruption was recorded on September 17. The volcano was about 270 miles away south of Tokyo. Several expeditions went out to study the volcanic activity of Mejin-sho and establish its exact location in the sea. The ship of the Department of Maritime Security of Japan was the first to arrive in the area of ​​the eruption. Found in the ocean new island.

It had an almost round shape and did not exceed 150 m in diameter. This piece of land rose almost 30 m above the ocean level. The volcano acted in full force, throwing red-hot lava, huge stones and ash to the surface. Eruptions followed one after another at intervals of a few seconds. Over time, the intervals between eruptions increased, but at the same time their intensity increased.

Several days passed, when suddenly on the night of September 22 volcanic island disappeared. But in all the following days of September, the Mejin-sho continued to manifest itself rapidly. Twice or even three times a day there were lava eruptions.

The volcano was still active when two Japanese ships arrived in the area. From the training vessel Shinio Maru of the Tokyo Fisheries Institute, they managed to take photographs, measure the strength of the eruptions that occurred on September 22 and 23, and also make a number of other observations. All this time, the ship kept at a considerable distance from the Mejin-sho. Other precautions were taken as well.

The second ship Kayo Maru 5 of the Japanese Hydrographic Office arrived in the area of ​​the eruption on September 24th. By this time, all traces of the volcanic island had already disappeared from the surface of the ocean. Apparently, the ship came too close to the volcano and became the victim of another eruption. Kayo Maru 5 and its crew of twenty-two sailors and seven scientists disappeared without a trace. That the ship was lost in a volcanic eruption, say many facts. In particular, it has been established for certain that on the day of the disaster, at 12:30 pm, one of the most powerful lava eruptions occurred.

Intensive searches, ships undertaken by the authorities, at first did not yield results. However, the fragments of Kayo Maru 5 were later found, covered with pieces of pumice, similar in composition to that which was thrown out by the Mejin-sho volcano.

A special place in history sea ​​adventures occupies the story that took place in 1962 in the waters of Antarctica with two South African ships. For one of them, the RSA supply ship, a fiery flash under Antarctic ice was saving, for the second - disastrous. For 10 days, RSA was in ice mites. The danger of being crushed by the ice grew. The crew was about to leave the ship and land on the ice. Suddenly there was an explosion. From the bottom of the ocean fire lava rises. The ice field is broken. An underwater volcano destroyed the ice, and the SAR was on clean water. Pieces of pumice thrown out by the volcano on the sea surface clogged the underwater holes in the hull. The ship did not experience any other troubles. None of his crew members were injured.

The second South African ship, which at that time was making its way to the aid of the SAR, also found itself in a zone of volcanic activity, almost at the source of the eruption and suffered a disaster. His crew had to escape on boats.

Another danger arises from volcanic eruptions. We are talking about volcanic ash, which, like thick fog, makes navigation difficult.

Two such cases occurred in 1963.

The Soviet ship Georgia was returning from Indonesia to its native shores. On May 17, the ship was sailing the Java Sea when a volcano erupted on the island of Java. Brown pumice dust began to fall intensively on the sea. Visibility has deteriorated sharply. Nothing could be made out at a distance of less than 100 m. As soon as the sailors went on deck, the dust clogged the nasopharynx and blinded their eyes. To prevent dust from penetrating into the premises, it was necessary to batten down the doors and portholes, turn off the ventilation. By noon there was complete darkness. The captain was forced to slow down and move forward with the help of radar. Volcanic precipitation fell throughout the day. The layer of dust in some places on the deck reached 20 mm.

In another case, the volcanic ash of the Krymsky volcano in Kamchatka was carried by the wind for 300 km and fell over Pacific Ocean. An ash cloud swept over Petropavlovsk-Kamchatsky. About 200 g of ash fell on one square meter. Later, the motor ship Norilsk met the ash cloud. This happened in the area of ​​Cape Piratkov. The sun had gone down and visibility had dropped sharply. Sweetish gray dust began to settle on the ship. In a short time, she covered the superstructures and the deck of the ship. Norilsk walked in an ash cloud for about an hour.

There are still many unbridled forces in the arsenal of nature. They still amaze the imagination with their power and are still capable of bringing a lot of trouble to sailors. But man is not powerless, as in the old days, in front of them. He is more and more armed with knowledge, the ability to withstand the blows of the elements and with honor emerges victorious from the battle with them.

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