What is the name of a high wave on the sea? rogue waves

Over thousands of years of navigation, people have learned to deal with the dangers of the water elements. Directions indicate safe way, weather forecasters warn of storms, satellites monitor icebergs and other dangerous objects. However, it is still unclear how to protect yourself from a thirty-meter wave that suddenly appears for no apparent reason. Just fifteen years ago, mysterious rogue waves were considered fiction.

Sometimes the appearance of giant waves on the surface of the ocean is quite understandable and expected, but sometimes they are a real mystery. Often such a wave is a death sentence for any vessel. The name of these mysteries is rogue waves.

You will hardly find a sailor who has not been baptized by a storm. Because, to paraphrase famous saying, to be afraid of storms - do not go to sea. From the very dawn of navigation there was a storm best exam both courage and professionalism. And if the favorite theme of war veterans’ memories is past battles, then the “sea wolves” will certainly tell you about the whistling wind that blew away radio antennas and radars, and the huge roaring waves that almost swallowed their ship. Which, perhaps, was “the very best.”

But already 200 years ago there was a need to clarify the strength of the storm. Therefore, in 1806, the Irish hydrographer and admiral of the British fleet Francis Beaufort (1774-1875) introduced a special scale according to which the weather at sea was classified depending on the degree of influence of the wind on the water surface. It was divided into thirteen levels: from zero (complete calm) to 12 points (hurricane). In the twentieth century, with some changes (in 1946 it was 17-point), it was adopted by the International Meteorological Committee - including for the classification of winds on land. Since then, hats have been involuntarily taken off to a sailor who has gone through a 12-point “swell” - because they have at least heard what it is: huge heaving shafts, the tops of which are blown into continuous clouds of spray and foam by a hurricane wind.

However for terrible phenomenon, which regularly hits the southeastern tip of the North American continent, a new scale had to be invented in 1920. This is the five-point Saffir-Simpson hurricane scale, which evaluates not so much the power of the element itself, but the destruction it causes.

According to this scale, a hurricane of the first category (wind speed 119-153 km/h) breaks tree branches and causes some damage to small ships at the pier. A category three hurricane (179-209 km/h) knocks down trees, tears off roofs and destroys light prefabricated houses, and floods the coastline. The most terrible hurricane of the fifth category (more than 255 km/h) destroys most buildings and causes serious flooding - driving large masses of water onto land. This is exactly what happened to the infamous Hurricane Katrina, which hit New Orleans in 2005.

The Caribbean Sea, where up to ten hurricanes forming in the Atlantic sweep through each year between June 1 and November 30, has long been considered one of the most dangerous areas for navigation. And living on the islands of this basin is by no means safe - especially in such a poor country as Haiti - where there is neither a normal warning service nor the ability to evacuate from a dangerous coast. In 2004, Hurricane Jenny killed 1,316 people there. The wind, roaring like a squadron of jet planes, blew away dilapidated huts along with their occupants and brought palm trees down on people's heads. And foaming waves rolled towards them from the sea.

One can only imagine what the crew of a ship experiencing when it finds itself in the “heavy heat” of such a hurricane. However, it happens that ships do not die during a storm at all.

In April 2005, the cruise ship Norwegian Dawn, leaving the fabulous Bahamas, was heading to New York Harbor. The sea was slightly stormy, but the huge 300-meter ship could simply afford to ignore such disturbances. Two and a half thousand passengers had fun in restaurants, walked along the decks and took photographs for memory.

Suddenly the liner tilted sharply, and in the next seconds a gigantic wave crashed onto its side, knocking out the cabin windows. It swept through the ship, sweeping away sun loungers in its path, overturning boats and the Jacuzzi installed on the 12th deck, knocking passengers and sailors off their feet.

“It was pure hell,” said James Fraley, one of the passengers who was celebrating his honeymoon on the liner with his wife. — Streams of water rolled over the decks. We started calling family and friends to say goodbye, deciding that the ship was sinking.”

So the Norwegian Dawn encountered one of the most mysterious and terrible ocean anomalies - a giant rogue wave. In the West they received various names: freak, rogue, rabid-dog, giant waves, cape rollers, steep wave events, etc.

The ship was very lucky - it escaped with only minor damage to the hull, property washed overboard and injured passengers. But the wave that suddenly hit him didn’t get its ominous nickname for nothing. The liner could well have suffered the fate of the Hollywood Poseidon, which turned upside down in the film of the same name. Or, even worse, simply break in half and drown, becoming the second Titanic.

Back in 1840, during his expedition, the French navigator Dumont d'Urville (Jules Sebastien Cesar Dumont d'Urville, 1792-1842) observed a giant wave about 35 m high. But his message at a meeting of the French Geographical Society only caused ironic laughter. None of the scientists could believe that such waves could exist.

They began to study this phenomenon seriously only after the English cargo ship Derbyshire sank off the coast of Japan in 1980. As the examination showed, the ship, almost 300 meters long, was destroyed by a gigantic wave, which pierced the main cargo hatch and flooded the hold. 44 people died. In the same year, the oil tanker Esso Languedoc collided with a rogue wave east of the coast of South Africa.

“It was stormy, but not very strong,” the English magazine New Scientist quoted senior mate Philippe Lijour as saying. “Suddenly, from the stern, a huge wave, many times higher than all the others. It covered the entire ship, even the masts disappeared under the water.”

While the water was rolling along the deck, Philip managed to grab a photo of it. According to his estimates, the shaft shot up at least 30 meters. The tanker was lucky - it remained afloat. However, these two cases were the last straw, causing companies involved in the export and import of raw materials to panic. After all, it was believed that transporting it on giant ships was not only more economically profitable, but also safer - they say, such ships, which are “knee-deep in the sea,” are not afraid of any storm.

Alas! Between 1969 and 1994 alone, twenty-two supertankers sank or were seriously damaged in the Pacific and Atlantic oceans when encountering such waves, killing five hundred and twenty-five people. Twelve more similar tragedies occurred during this time in Indian Ocean. Offshore oil platforms also suffer from them. Thus, on February 15, 1982, a rogue wave overturned a Mobil Oil rig in the Newfoundland Bank area, killing eighty-four workers.

But also large quantity Small vessels (trawlers, pleasure yachts) when encountering rogue waves simply disappear without a trace, without even having time to send a distress signal. Giant water shafts as high as a fifteen-story building crushed or smashed small boats. The skill of the helmsmen did not help either: if someone managed to turn his nose towards the wave, then his fate was the same as that of the unfortunate fishermen in the film “The Perfect Storm”: the boat, trying to climb onto the crest, became vertical - and fell off down, falling into the abyss with the keel up.

Rogue waves usually occur during a storm. This is the same “ninth wave” that sailors are so afraid of - but, fortunately, not everyone happens to encounter it. If the height of ordinary storm crests is on average 4-6 meters (10-15 for a hurricane), then a wave that suddenly appears among them can reach a height of 25-30 meters.

However, rarer, and much more dangerous rogue waves appear in fairly calm weather - and this is not called anything other than an anomaly. At first they tried to justify them by the collision of sea currents: most often such waves appear at the Cape of Good Hope (the southern tip of Africa), where warm and cold currents connect. It is there that sometimes the so-called “three sisters” - three giant waves following one after another, upon which, rising, the supertankers break under their own weight.

But reports of deadly waves also came from other parts of the planet. They were also seen in the Black Sea - “only” ten meters high, but this was enough to capsize several small trawlers. In 2006, such a wave hit the British ferry Pont-Aven, which was traveling along the Pas-de-Calais Strait. She broke windows at the height of the sixth deck, injuring several passengers.

What causes the surface of the sea to suddenly rise up like a gigantic wave? Both serious scientists and amateur theorists develop a variety of hypotheses. The waves are recorded by satellites from space, their models are created in research basins, but they still cannot explain the reasons for all cases of rogue waves.

But the causes that cause the most terrible and destructive sea waves - tsunamis - have long been established and studied.

Seaside resorts are not always a paradise on the planet. Sometimes they become a real hell - when unexpectedly, in clear and sunny weather, gigantic shafts of water fall on them, washing away entire cities along the way.

...These images went around the whole world: unsuspecting tourists who, out of curiosity, went to the bottom of the suddenly receding sea to pick up a few shells and starfish. And suddenly they notice a rapidly approaching wave appearing on the horizon. The poor people are trying to escape, but a muddy, seething stream overtakes and captures them, and then rushes towards the whitewashed houses on the coast...

The disaster that occurred on December 26, 2004 in South-East Asia, shocked humanity. A giant wave swept away everything in its path, spreading across the Indian Ocean. Sumatra and Java, Sri Lanka, India and Bangladesh, Thailand were affected, and the wave even reached the east coast of Africa. The Andaman Islands went under water for several hours - and the local aborigines miraculously survived, saving themselves on the treetops. As a result of the disaster, more than 230 thousand people died; it took more than a month to find and bury them all. Millions of people were left homeless and without a means of livelihood. The tragedy turned out to be one of the largest and most tragic natural disasters in the history of mankind.

“A high wave entering the harbor” is how the word “tsunami” is translated from Japanese. In 99% of cases, tsunamis are caused by an earthquake of the ocean floor when it suddenly drops or rises. Just a few meters, but over a huge area - and this is enough to cause a wave spreading out from the epicenter in a circle. In the open sea, its speed reaches 800 km/h, but it is almost impossible to notice it, since its height is only about one, maximum two meters - but with a length of up to several kilometers. The ship under which it passes will only rock slightly - that is why, having received a warning, ships strive to leave the ports and go as far out to sea as possible.

The situation changes when the wave approaches the shore, in shallow water (enters the harbor). Its speed and length drop sharply, but its height increases - up to seven, ten or more meters (cases of 40-meter tsunamis are known). It bursts onto the land like a solid wall and has enormous energy - that’s why tsunamis are so destructive and can travel several hundred and sometimes thousands of meters along the ground. Moreover, each tsunami hits twice. At first, when it hits the shore, flooding it. And then - when the water begins to return to the sea, carrying away those who survived the first blow.

In 1755, a tsunami caused by a devastating earthquake killed 40 thousand Portuguese. A formidable ocean wave hit Japan on June 15, 1896: the height of the wave reached 35 meters, then 27 thousand people died, and all coastal towns and villages in an 800 km strip ceased to exist. In 1992, a tsunami killed 2,000 Indonesian islanders.

Experienced residents seaside towns and villages in seismically dangerous areas know: as soon as an earthquake begins, and after it a sudden and rapid ebb of tide, you need to drop everything and run without looking back to higher ground or inland. In a number of regions regularly affected by tsunamis (Japan, Sakhalin, Hawaii), special services warnings. They record an earthquake in the ocean and immediately give an alarm to all the media and through street loudspeakers.

But tsunamis can be caused not only by earthquakes. The explosion of the Krakatoa volcano in 1883 caused a wave that struck the islands of Java and Sumatra, washing away more than 5,000 fishing boats, about 300 villages and killing more than 36,000 people. And in Lituya Bay (Alaska), a tsunami caused a landslide that collapsed a mountainside into the sea. The wave spread over a limited area, but its height was enormous - over three hundred meters, while hitting the opposite shore, it licked the bushes at an altitude of 580 meters!

However, this is not the limit. The largest and most destructive waves are generated when large meteorites or asteroids fall into the ocean. True, fortunately, this happens extremely rarely - once every few million years. But this cataclysm is taking on the scale of a truly planetary flood. For example, German scientists found that about 200 million years ago a large cosmic body. It raised a tsunami over one kilometer high, which burst onto the continental plains, destroying all life in its path.

Rogue waves should not be confused with tsunamis: tsunamis arise as a result of seismic phenomena and gain great height only close to the coast, while rogue waves can appear without known reasons, in almost any part of the sea, with light winds and relatively low waves. Tsunamis are dangerous for coastal structures and ships close to the shore, while a rogue wave can destroy any ship or offshore structure that comes its way.

Where do these monsters come from? Until recently, oceanographers believed that they were formed as a result of well-known linear processes. According to the current theory big waves They are simply a product of interference, in which small waves combine into one large one.

In some cases, this is exactly what happens. A good example of this is the waters off Cape Agulhas, the southernmost point of the African continent. The Atlantic and Indian oceans meet there. Ships rounding the cape are regularly attacked by huge waves, which are formed as a result of the collision of the fast Agulyas Current and winds blowing from the south. The movement of the water slows down, and the waves begin to pile on top of each other, forming giant waves. In addition, super waves can often be found in the Gulf Stream, the Kuroshio Current south of the coast of Japan and in the notorious waters off Cape Horn, where the same thing happens - fast currents collide with opposing winds.

However, the interference mechanism does not apply to all giant waves. Firstly, it is in no way suitable for justifying the appearance of giant waves in places like the North Sea. There are no traces of fast currents there.

Secondly, even if interference occurs, giant waves should not occur so often. Their absolute majority should gravitate towards average height- some are a little higher, others a little lower. Double-sized giants should appear no more than once during human life. However, in reality everything is completely different. Observations by oceanographers suggest that most waves are smaller than average, and true giants are much more common than we think. Orthodox oceanography gets a hole below the waterline.

A rogue wave is usually described as a rapidly approaching wall of water of enormous height. In front of it moves a depression several meters deep - a “hole in the sea.” Wave height is usually specified as the distance from the highest point of the crest to the lowest point of the trough. By appearance"Rogue waves" are divided into three main types: "white wall", "three sisters" (a group of three waves), a single wave ("single tower").

To appreciate what they can do, just look at the photo of the Willstar above. The surface on which such a wave hits can experience pressure of up to one hundred tons per square meter (about 980 kilopascals). A typical twelve-meter wave threatens only six tons per square meter. Most modern vessels can support up to 15 tons per square meter.

According to the observations of the US National Oceanic and Atmospheric Administration (NOAA), rogue waves can be dissipated and non-dispersed. Those who do not disperse can travel quite a long distance by sea: from six to ten miles. If the ship notices a wave from afar, you can take some action. Those that dissipate appear literally out of nowhere (apparently, such a wave attacked the “Taganrog Bay”), collapse and disappear.

According to some experts, rogue waves are dangerous even for helicopters flying low over the sea: first of all, rescue ones. Despite the seeming improbability of such an event, the authors of the hypothesis believe that it cannot be ruled out and that at least two cases of death of rescue helicopters are similar to the result of a giant wave.

Scientists are trying to figure out how energy in the ocean is redistributed in such a way that the formation of rogue waves becomes possible. Behavior nonlinear systems, similar sea surface, is extremely difficult to describe. Some theories are used to describe the occurrence of waves nonlinear equation Schrödinger. Some are trying to apply existing descriptions of solitons - single waves unusual nature. In a recent study on this topic, scientists were able to reproduce a very similar phenomenon in electromagnetic waves, however, this has not yet led to practical results.

Some empirical data on the conditions under which rogue waves are more likely to occur are still known. So, if the wind drives waves against a strong current, this can lead to the appearance of high, steep waves. For example, the Cape Agulhas current (in which the Wilstar suffered) is notorious for this. Other high-risk areas include the Kuroshio Current, Gulf Stream, North Sea and surrounding areas.

Experts call the following prerequisites for the occurrence of a rogue wave:

1. area of low pressure;
2. wind blowing in one direction for more than 12 hours in a row;
3. waves moving at the same speed as the area of low pressure;
4. waves moving against a strong current;
5. fast waves catching up with slower waves and merging with them.

The absurd nature of rogue waves, however, is manifested in the fact that they can also arise when the listed conditions are not met. This unpredictability is the main mystery for scientists and danger for sailors.

They managed to escape

1943, North Atlantic. The cruise ship Queen Elizabeth falls into a deep trough and is subjected to two powerful wave shocks in a row, which cause serious damage to the bridge - twenty meters above the waterline.

1944 Indian Ocean. The British Navy cruiser Birmingham falls into a deep hole, after which a gigantic wave crashes onto its bow. According to the notes of the ship's commander, the deck, located at an altitude of eighteen meters from sea level, is flooded with knee-deep water.

1966, North Atlantic. On the way to New York, the Italian steamship Michelangelo is hit by a wave eighteen meters high. Water rushes onto the bridge and into the first class cabins, killing two passengers and one crew member.

1995, North Sea. The floating drilling rig Veslefrikk B, owned by Statoil, was seriously damaged by a giant wave. According to one of the crew members, a few minutes before the impact he saw a “wall of water.”

1995 North Atlantic. While sailing to New York, the cruise ship Queen Elizabeth 2 encounters a hurricane and takes on a twenty-nine meter high wave on its bow. “It felt like we were crashing into the White Cliffs of Dover,” says Captain Ronald Warrick.

1998, North Atlantic. BP Amoco's floating production platform "Schihallion" is hit by a giant wave, which destroys its tank superstructure at a height of eighteen meters from the water level.

2000, North Atlantic. After receiving a distress call from a yacht 600 miles from the Irish port of Cork, the British cruise liner Oriana is hit by a twenty-one meter high wave.

6. Sea waves.

The surface of the sea is always moving, even with complete calm. But then the wind blew, and ripples immediately appeared on the water, which turned into waves the faster the stronger the wind blew. But no matter how strong the wind is, it cannot cause waves larger than certain maximum sizes.

Waves generated by wind are considered short. Depending on the strength and duration of the wind, their length and height range from several millimeters to tens of meters (in a storm, the length of wind waves reaches 150-250 meters).

Observations of the sea surface show that waves become strong even at wind speeds of more than 10 m/s, while the waves rise to a height of 2.5-3.5 meters, crashing onto the shore with a roar.

But then the wind turns storm, and the waves reach enormous sizes. There are many places on the globe where very strong winds blow. For example, in the northeastern part of the Pacific Ocean east of the Kuril and Commander Islands, as well as east of the main Japanese island of Honshu, in December-January maximum wind speeds are 47-48 m/s.

In the South Pacific, maximum wind speeds are observed in May in the area northeast of New Zealand (49 m/s) and near the Antarctic Circle in the area of Balleny and Scott Islands (46 m/s).

We perceive speeds expressed in kilometers per hour better. So the speed of 49 m/s is almost 180 km/h. Already at a wind speed of more than 25 m/s, waves 12-15 meters high rise. This degree of excitement is rated 9–10 points as a severe storm.

Measurements have established that the height of the storm wave in the Pacific Ocean reaches 25 meters. There are reports that waves up to 30 meters high have been observed. True, this assessment was made not on the basis of instrumental measurements, but approximately, by eye.

In the Atlantic Ocean maximum height wind waves reach 25 meters.

The length of storm waves does not exceed 250 meters.

But the storm stopped, the wind died down, but the sea still did not calm down. Like the echo of a storm on the sea arises swell. Swell waves (their length reaches 800 meters or more) move over enormous distances of 4-5 thousand km and approach the shore at a speed of 100 km/h, and sometimes higher. In the open sea, low and long swell waves are invisible. When approaching the shore, the speed of the wave decreases due to friction with the bottom, but the height increases, the front slope of the wave becomes steeper, foam appears at the top, and the crest of the wave crashes onto the shore with a roar - this is how the surf appears - a phenomenon equally colorful and majestic, as dangerous as it is. The force of the surf can be colossal.

When faced with an obstacle, the water rises to a great height and damages lighthouses, port cranes, breakwaters and other structures. Throwing stones from the bottom, the surf can damage even the highest and most distant parts of lighthouses and buildings. There was a case when the surf tore a bell from one of the English lighthouses from a height of 30.5 meters above sea level. The surf on our Lake Baikal sometimes in stormy weather throws stones weighing up to a ton at a distance of 20-25 meters from the shore.

During storms in the Gagra region, the Black Sea eroded and swallowed up a 20-meter-wide coastal strip over 10 years. When approaching the shore, the waves begin to destructive work from a depth equal to half their length in the open sea. Thus, with a storm wave length of 50 meters, characteristic of seas such as the Black or Baltic, the impact of waves on the underwater coastal slope begins at a depth of 25 m, and with a wave length of 150 m, characteristic of the open ocean, such impact begins already at a depth of 75 m.

Current directions affect size and strength sea waves. With countercurrents, the waves are shorter but higher, and with countercurrents, on the contrary, the height of the waves decreases.

Near the boundaries of sea currents, waves of unusual shapes, resembling a pyramid, and dangerous whirlpools often appear, which suddenly appear and just as suddenly disappear. In such places, navigation becomes especially dangerous.

Modern ships have high seaworthiness. But it happens that, having traveled many miles across a stormy ocean, ships find themselves in even greater danger than at sea when they arrive in their home bay. The powerful surf, breaking the multi-ton reinforced concrete breakwaters of the dam, is capable of turning even a large ship into a pile of metal. In a storm, it is better to wait until entering the port.

To combat the surf, specialists in some ports tried to use air. A steel pipe with numerous small holes was laid on the seabed at the entrance to the bay. Air under high pressure was supplied into the pipe. Escaping from the holes, streams of air bubbles rose to the surface and destroyed the wave. This method has not yet found widespread use due to insufficient efficiency. Rain, hail, ice and thickets of marine plants are known to calm waves and surf.

Sailors have long noticed that fat poured overboard smoothes the waves and reduces their height. Animal fat, such as whale blubber, works best. The effect of vegetable and mineral oils is much weaker. Experience has shown that 50 cm 3 of oil is enough to reduce disturbances over an area of 15 thousand square meters, that is, 1.5 hectares. Even a thin layer of oil film noticeably absorbs energy oscillatory movements water particles.

Yes, that's all true. But, God forbid, we under no circumstances recommend that captains of sea vessels stock up on fish or whale oil before a voyage in order to then pour these fats into the waves to calm the ocean. After all, things can reach such an absurdity that someone will start pouring oil, fuel oil, and diesel fuel into the sea in order to appease the waves.

It seems to us that The best way combating waves consists of a well-organized weather service that notifies ships in advance about the expected place and time of the storm and its expected strength, good navigational and pilot training of sailors and coastal personnel, as well as constant improvement of the design of ships in order to improve their seaworthiness and technical capabilities. reliability.

For scientific and practical purposes, you need to know the full characteristics of the waves: their height and length, the speed and range of their movement, the power of an individual water shaft and the wave energy in a particular area.

The first measurements of waves were made in 1725 by the Italian scientist Luigi Marsigli. At the end of the 18th – beginning of the 19th centuries, regular observations of waves and their measurements were carried out by Russian navigators I. Kruzenshtern, O. Kotzebue and V. Golovin during their voyages across the World Ocean. The technical basis for measurements in those days was very weak; of course, there were no special instruments for measuring waves on the sailing ships of that time.

Currently, for these purposes, there are very complex and precise instruments that are equipped with research vessels that carry out not only measurements of wave parameters in the ocean, but also much more complex scientific work. The ocean still holds many secrets, the disclosure of which could bring significant benefits to all of humanity.

When they talk about the speed of movement of waves, that waves run up and roll onto the shore, you need to understand that it is not the water mass itself that moves. The water particles that make up the wave practically do not move forward. Only the wave form moves in space, and water particles in the agitated sea perform oscillatory movements in the vertical and, to a lesser extent, in horizontal plane. The combination of both oscillatory movements leads to the fact that the water particles in the waves actually move in circular orbits, the diameter of which is equal to the height of the wave. The oscillatory movements of water particles quickly decrease with depth. Precise instruments show, for example, that with a wave height of 5 meters (storm wave) and a length of 100 meters, at a depth of 12 meters the diameter of the wave orbit of water particles is already 2.5 meters, and at a depth of 100 meters - only 2 centimeters.

Long waves, unlike short and steep ones, transmit their motion to great depths. In some photographs of the ocean floor down to a depth of 180 meters, researchers noted the presence of sand ripples formed under the influence of oscillatory movements of the bottom layer of water. This means that even at such a depth, the surface waves of the ocean make themselves felt.

Is it necessary to prove what danger a storm wave poses to ships?

In the history of navigation, there are countless tragic incidents at sea. Small longboats and high-speed sailing ships, along with their crews, perished. Modern ocean liners are not immune to the insidious elements.

On modern ocean-going ships, among other devices and instruments that ensure safe navigation, pitch stabilizers are used, which prevent the ship from getting an unacceptably large roll on board. In some cases, powerful gyroscopes are used for this, in others, retractable hydrofoils are used to level the position of the ship’s hull. Computer systems on ships are in constant communication with meteorological satellites and other spacecraft, telling navigators not only the location and strength of storms, but also the most favorable course in the ocean.

In addition to surface waves, there are also internal waves in the ocean. They form at the interface between two layers of water of different densities. These waves travel slower than surface waves, but can have greater amplitude. Internal waves are detected by rhythmic changes in temperature at different depths of the ocean. The phenomenon of internal waves has not yet been sufficiently studied. It has only been established that waves arise at the boundary between layers with lower and higher densities. The situation may look like this: there is complete calm on the surface of the ocean, but at some depth a storm is raging; along the length, internal waves are divided, like ordinary surface ones, into short and long. For short waves, the length is much less than the depth, while for long waves, on the contrary, the length exceeds the depth.

There are many reasons for the appearance of internal waves in the ocean. The interface between layers with different densities can be thrown out of balance by a moving large vessel, surface waves, or sea currents.

Long internal waves manifest themselves, for example, in this way: a layer of water, which is a watershed between more dense (“heavy”) and less dense (“light”) water, first rises slowly, for hours, and then suddenly falls by almost 100 meters. Such a wave is very dangerous for submarines. After all, if a submarine sank to a certain depth, it means it was balanced by a layer of water of a certain density. And suddenly, unexpectedly, a layer of less dense water appears under the hull of the boat! The boat immediately falls into this layer and sinks to the depth where the less dense water can balance it. But the depth may be such that the water pressure exceeds the strength of the hull of the submarine, and it will be crushed in a matter of minutes.

According to the conclusion of American experts who investigated the causes of the death of the nuclear submarine Thresher in 1963 in the Atlantic Ocean, this submarine found itself in exactly this situation and was crushed by enormous hydrostatic pressure. Naturally, there were no witnesses to the tragedy, but the version of the cause of the disaster is confirmed by the results of observations carried out by research ships in the area where the submarine sank. And these observations showed that internal waves with a height of more than 100 meters often arise here.

A special type are the waves that arise on the sea when there is a change atmospheric pressure. They're called seiches And microseiches. Oceanology studies them.

So, we talked about both short and long waves at sea, both surface and internal. Now let us remember that long waves arise in the ocean not only from winds and cyclones, but also from processes occurring in the earth’s crust and even in the deeper regions of the “interior” of our planet. The length of such waves is many times greater than the longest ocean swell waves. These waves are called tsunami. The height of tsunami waves is not much higher than large storm waves, but their length reaches hundreds of kilometers. The Japanese word "tsunami" roughly translates to "harbour wave" or "coastal wave" . To some extent, this name conveys the essence of the phenomenon. The point is that in open ocean a tsunami poses no danger. At a sufficient distance from the coast, the tsunami does not rage, does not cause destruction, and cannot even be noticed or felt. All tsunami disasters occur on the shore, in ports and harbors.

A tsunami occurs most often from earthquakes caused by displacement tectonic plates earth's crust, as well as from strong volcanic eruptions.

The mechanism for the formation of a tsunami is most often as follows: as a result of the displacement or rupture of a section of the earth's crust, a sudden rise or fall of a significant section of the seabed occurs. As a result, a rapid change in volume occurs body of water, and elastic waves appear in the water, propagating at a speed of about one and a half kilometers per second. These powerful elastic waves generate tsunamis on the ocean surface.

Having arisen on the surface, tsunami waves scatter in circles from the epicenter. At the point of origin, the height of the tsunami wave is small: from 1 centimeter to two meters (sometimes up to 4-5 meters), but more often in the range from 0.3 to 0.5 meters, and the wave length is huge: 100-200 kilometers. Invisible in the ocean, these waves, approaching the shore, like wind waves, become steeper and higher, sometimes reaching a height of 10-30 and even 40 meters. Having hit the shore, tsunamis destroy and destroy everything in their path and, worst of all, bring death to thousands, and sometimes tens and even hundreds of thousands of people.

The speed of tsunami propagation can be from 50 to 1000 kilometers per hour. Measurements show that the speed of a tsunami wave varies proportionally square root from the depths of the sea. On average, a tsunami rushes across the open ocean at a speed of 700-800 kilometers per hour.

Tsunamis are not regular events, but they are no longer rare.

In Japan, tsunami waves have been recorded for more than 1,300 years. On average for the Land of the Rising Sun destructive tsunami struck every 15 years (small tsunamis that did not have serious consequences are not taken into account).

Most tsunamis occur in the Pacific Ocean. Tsunamis raged in the Kuril, Aleutian, Hawaiian, and Philippine islands. They also attacked the coasts of India, Indonesia, North and South America, as well as European countries located on the Atlantic coast and in the Mediterranean.

The last most destructive tsunami attack was the terrible flood of 2004 with enormous destruction and loss of life, which had seismic causes and originated in the center of the Indian Ocean.

In order to have an idea of the specific manifestations of a tsunami, you can refer to numerous materials that describe this phenomenon.

We will give just a few examples. This is how the results of the earthquake that occurred in the Atlantic Ocean not far from the Iberian Peninsula on November 1, 1755 were described in the press. It caused terrible destruction in the capital of Portugal, Lisbon. The ruins of the once majestic building still tower in the city center convent Karmo that was never restored. These ruins remind the people of Lisbon of the tragedy that struck the city on November 1, 1755. Shortly after the earthquake, the sea receded, and then a wave 26 meters high hit the city. Many residents, fleeing the falling debris of buildings, left the narrow streets of the city and gathered on the wide embankment. The surging wave washed away 60 thousand people into the sea. Lisbon was not completely flooded because it is located on several high hills, but in low-lying areas the sea flooded the land up to 15 kilometers from the coast.

On August 27, 1883, there was a powerful eruption of the Kratau volcano, located in the Sunda Strait of the Indonesian archipelago. Clouds of ash rose into the sky, a strong earthquake arose, generating a wave 30-40 meters high. In a few minutes, this wave washed away all the villages located on the low shores of western Java and southern Sumatra into the sea, killing 35 thousand people. At a speed of 560 kilometers per hour, tsunami waves swept through the Indian and Pacific oceans, reaching the shores of Africa, Australia and America. Even in the Atlantic Ocean, despite its isolation and remoteness, in some places (France, Panama) a certain rise in water was noted.

On June 15, 1896, the incoming tsunami waves destroyed 10 thousand houses on the eastern coast of the Japanese island of Honshu. As a result, 27 thousand inhabitants died.

It is impossible to fight a tsunami. But it is possible and necessary to minimize the damage they cause to people. Therefore, now in all seismically active areas where there is a threat of tsunami waves, special warning services have been created, equipped with the necessary equipment that receives signals about changes in the seismic situation from sensitive seismographs located in different places on the coast. The population of such areas is regularly instructed on the rules of behavior in the event of a threat of tsunami waves. Tsunami warning services in Japan and the Hawaiian Islands have repeatedly given timely warning signals about the approach of a tsunami, thereby saving more than one thousand human lives.

All types of currents and waves are characterized by the fact that they carry colossal energy - thermal and mechanical. But humanity is not able to use this energy, unless, of course, we count attempts to use the energy of ebbs and flows. One of the scientists, probably a lover of statistics, calculated that the power of sea tides exceeds 1000000000 kilowatts, and that of all the rivers of the globe - 850000000 kilowatts. Energy of one square kilometer stormy sea is estimated at billions of kilowatts. What does this mean for us? Only that a person cannot use even a millionth part of the energy of tides and storms. To some extent, people use wind energy to generate electricity and other purposes. But that, as they say, is another story.

Killer waves or wandering waves, monster waves are giant single waves 20-30 meters high, sometimes appearing larger in the ocean and exhibiting behavior uncharacteristic of sea waves.
Killer waves have a different origin from tsunamis and have long been considered fiction.

However, within the framework of the MaxWave project (“ Maximum Wave", which involved monitoring the surface of the world's oceans using the European Space Agency's (ESA) ERS-1 and ERS-2 radar satellites, was recorded over three weeks throughout to the globe more than 10 single giant waves, the height of which exceeded 25 meters.

This forced the scientific community to reconsider their views, and despite the impossibility of mathematical modeling of the process of the occurrence of such waves, to recognize the fact of their existence.

1 Robber waves are waves whose height is more than twice the significant wave height.

Significant wave heights are calculated for a given period in a given region. For this purpose, a third of all recorded waves with greatest height, and their average height is found.

2 The first reliable instrumental evidence of the appearance of a rogue wave is considered to be the readings of instruments on the Dropner oil platform located in the North Sea.

On January 1, 1995, with a significant wave height of 12 meters (which is a lot, but quite common), a 26-meter wave suddenly appeared and hit the platform. The nature of the equipment damage corresponded to the specified wave height.

3 Robber waves can appear for no known reason in light winds and relatively small waves, reaching a height of 30 meters.

This is a mortal threat to even the most modern ships: the surface on which a giant wave crashes can experience pressure of up to 100 tons per square meter.

4 The most probable zones of wave formation in this case are called zones of sea currents, since in them the disturbances caused by the inhomogeneity of the current and the unevenness of the bottom are the most constant and intense. Interestingly, such waves can be both crests and troughs, which is confirmed by eyewitnesses. Further research attracts nonlinearity effects in wind waves that can lead to the formation of small groups of waves (packets) or individual waves (solitons) that can travel long distances without significant change its structure. Similar packages have also been observed many times in practice. Characteristic Features such groups of waves, confirming this theory, is that they move independently of other waves and have a small width (less than 1 km), and the heights drop sharply at the edges.

5 In 1974, off the coast South Africa A rogue wave severely damaged the Norwegian tanker Wilstar.

Some scientists suggest that between 1968 and 1994, rogue waves destroyed 22 supertankers (and it is very difficult to destroy a supertanker). Experts, however, disagree on the causes of many shipwrecks: it is unknown whether rogue waves were involved.

6 In 1980, the Russian tanker Taganrog Bay collided with a rogue wave". Description from the book by I. Lavrenov. " Math modeling wind waves in a spatially inhomogeneous ocean”, op. based on the article by E. Pelinovsky and A. Slyunyaev. The sea state after 12 o'clock also decreased slightly and did not exceed 6 points. The ship's speed was slowed down to the very minimum, it obeyed the rudder and "played out" well on the wave. The tank and deck were not filled with water. Suddenly, at 13:01, the bow of the ship dropped slightly, and suddenly, at the very stem at an angle of 10-15 degrees to the ship's heading, the crest of a single wave was noticed, which rose 4-5 m above the forecastle (the bulwark of the forecastle was 11 m). The ridge instantly collapsed on the tank and covered the sailors working there (one of them died). The sailors said that the ship seemed to smoothly go down, gliding along the wave, and “buried” in the vertical section of its front part. No one felt the impact; the wave smoothly rolled over the tank of the ship, covering it with a layer of water more than 2 m thick. There was no continuation of the wave either to the right or to the left.

7 Radar data analysis oil platform Goma in the North Sea showed, that over 12 years, 466 rogue waves were recorded in the available field of view.

While theoretical calculations showed that in this region the appearance of a rogue wave could occur approximately once every ten thousand years.

8 A rogue wave is usually described as a rapidly approaching wall of water of enormous height.

In front of it moves a depression several meters deep - a “hole in the sea.” Wave height is usually specified as the distance from the highest point of the crest to the lowest point of the trough. Based on their appearance, rogue waves are divided into three main types: “white wall”, “three sisters” (a group of three waves), and a single wave (“single tower”).

9 According to some experts, rogue waves are dangerous even for helicopters flying low over the sea: first of all, rescue ones.

Despite the seeming improbability of such an event, the authors of the hypothesis believe that it cannot be ruled out and that at least two cases of death of rescue helicopters are similar to the result of a giant wave.

10 In the 2006 film Poseidon, the passenger liner Poseidon fell victim to a rogue wave. sailing in the Atlantic Ocean on New Year's Eve.

The wave turned the ship upside down, and a few hours later it sank.

Based on materials:

Video on the topic “Killer Waves”:

It is known that waves are a product of winds. They arise due to the fact that air currents interact with the upper layers of the water column, moving them. Depending on the wind speed, the wave can travel over vast distances. As a rule, due to a decrease in the level kinetic energy the waves do not have time to reach land. The weaker the wind currents, the correspondingly smaller the wave.

The emergence of waves occurs naturally. Here everything depends on the wind: its speed, the area covered. Typically, the ratio of the maximum value of a wave's height to its width is 7:1. Yes, hurricane medium strength can generate waves up to twenty meters high. Such waves look stunning: they foam and make a monstrous sound as they move. Watching this giant wave is like watching a horror movie with special effects.

In the 33rd year of the last century, the sailors of the Ramapo ship recorded the largest ocean wave. Its height was thirty-four meters! Waves of this height are called “killers”, as they can easily swallow huge ships. Scientists believe that given value wave heights are not the limit. Theoretically, the maximum possible wave height is sixty meters.

In addition to winds, the cause of waves can be landslides, volcanic eruptions, earthquakes, meteorite falls, explosions nuclear bombs. The high power pulse generates a wave called a tsunami. These waves are characterized long length. The distance between tsunami crests can be tens of kilometers. In view of this, the height of such waves in the ocean is, at most, a meter. At the same time, the speed indicators are shocking: tsunamis can travel eight hundred kilometers in one hour. Due to length compression as a tsunami approaches land, the wave height increases. Therefore, near coastline The height of a tsunami is several times greater than the size of large wind waves.

Tsunamis can also occur due to tectonic displacements and faults in the ocean floor. At the same time, millions of tons of water begin to move sharply, moving at the speed of a jet plane. Such tsunamis are discouraging: while moving towards the coastline, the wave gains gigantic heights, and then covers the ground with a wall of water, absorbing everything with its power. The scale of such a disaster is difficult to underestimate: a tsunami could easily destroy an entire city.

The greatest likelihood of experiencing the harmful effects of a tsunami occurs in bays that have a fairly high shore. Such places are real traps for giant waves. They are capable of attracting tsunamis without any warning. From the shore it can be seen as if what is happening is the rising tide of the sea (or low tide). In extreme cases, you might think that a storm is coming. But within a few minutes a wave of indescribable proportions can engulf a vast area. Naturally, such a suddenness of the tsunami does not allow people to evacuate. Today there are very few places in the world where you can find a tsunami warning service. Therefore, as a rule, huge waves entail thousands of deaths and colossal destruction of land. You can remember the tsunami that occurred in 2004 in Thailand: it was a real disaster.\

In addition to bays with high shores, risk zones include areas where there is increased seismic activity. The Japanese islands are places that are constantly attacked by waves of different sizes. In 2011, a wave of forty meters high was found on the coast of one of the islands (Japan, Honshu). Then the tsunami caused an earthquake, which was the strongest in Japan ever. The earthquake and tsunami that year claimed the lives of fifteen thousand people. Many are considered missing: they were carried away by the wave.

This tsunami disaster is not the only one in Japanese history. In the eighteenth century (1741), a volcanic eruption occurred, resulting in a huge wave. The height of this tsunami was ninety meters. Then, in 2004, due to an earthquake in the Indian Ocean, the Japanese island of Java, as well as Sumatra, were attacked by a giant wave. That year, the tsunami took the lives of three hundred thousand inhabitants. It was the largest tsunami in the world (in terms of the number of lives lost).

In 1958, a tsunami struck Lituya Bay, which is located in Alaska. A wave whose height was five hundred twenty-four meters was recorded here. A huge landslide became an impulse, a push for the emergence of this monstrous wave, which moved at a speed of more than one hundred and fifty kilometers per hour.