The most common cause of waves in the oceans and seas is the wind: air gusts move the surface layers of water at a certain speed. Thus, the wind can disperse a wave at a speed of 95 km / h, the raised water column can reach 300 meters in length. Such waves are able to overcome gigantic distances, but, as a rule, wave energy is extinguished in the ocean, being consumed long before land. In the case when the wind subsides, the disturbances in the ocean become smaller and smooth out.
Patterns of wave formation
Wave length and height depend not only on wind speed. The influence and duration of the wind impact is great, and it also matters what area of the territory was covered by it. There is a regular correspondence: the maximum wave height is 1/7 of its length. For example, a breeze with a strength above the average forms waves whose height reaches 3 meters, a hurricane, which has a vast area, raises waves up to about 20 meters.
Big wave formation
In 1933, the sailors of the American ship Ramapo in the South African Agulhas noted the highest normal wave - it reached a height of 34 m. Waves of a similar height are popularly called "killer waves", since even a large ship can easily fall through and get lost in the distances between their crests. Theoretically, the height of such ordinary waves can reach 60 m, but in practice, such waves have never been recorded.
In addition to the normal, that is, the wind origin of waves, other causes of wave generation are also known:
- earthquake
- eruption
- large meteorites falling into the ocean
- landslides leading to a sharp change in the line of the coast
- nuclear weapons testing or other human activity
Tsunami
Tsunamis have the biggest waves. In fact, this is a serial wave caused by a certain impulse of enormous power. Tsunami waves are quite long, dips between peaks can reach more than 10 km. For this reason, a tsunami in the open ocean is not a big danger, since the wave height rarely reaches 20 cm, only in some (record) cases they can reach 1.5 m. But the speed of the tsunami develops grandiose - the waves propagate at a speed of 800 km / h. In the open sea, such waves are almost impossible to notice from a ship. Tsunami waves acquire their monstrous strength as they approach the coastline. Reflecting from the shore, the waves are compressed in length, and their destructive energy does not disappear anywhere. As a result, the wave amplitude—their height—increases. Of course, such waves are much more dangerous than wind waves, since they reach a much greater height.
The causes of the most terrifying tsunamis are significant disturbances in the topography of the ocean floor. These can be tectonic shifts or faults, in the event of which a billion tons of water moves at the speed of a jet aircraft over vast distances (as many as tens of thousands of kilometers). And it happens abruptly, immediately. A catastrophe is inevitable when a multibillion-dollar mass of water reaches the shore. Then the colossal energy of the waves is first directed to increase the amplitude, and then it falls on the coast with the entire powerful wall of water.
Tsunami in Sumatra in 2004 Bays with high shores are most often subject to dangerous tsunamis. Such places are real traps for serial waves. What is characteristic and at the same time scary is that a tsunami almost always strikes suddenly, visually the sea can be the same as during low tides, high tides or an ordinary storm, so people do not even think about timely evacuation. Unfortunately, special warning systems for the approach of giant waves have not been developed everywhere.
Tsunami risk zones are also seismically active areas. The word "tsunami" itself is of Japanese origin, since earthquakes are very frequent here and waves of various scales and sizes constantly attack the islands. There are also real giants among them, it is they who lead to human casualties. The earthquake of 2011, which occurred in the east of Honshu, gave rise to a powerful tsunami up to 40 m high. Japan has not yet known such earthquakes. The catastrophe had horrific consequences: the monstrous power of the waves dealt severe blows along the entire eastern coast of the island, taking away the lives of over 15 thousand people along with the earthquake, several thousand people are considered missing to this day.
A large-scale disaster on the islands of Java and Sumatra in 2004 turned into a tsunami, which was generated by a strong earthquake in the Indian Ocean. According to various sources, from 200 to 300 thousand people died - this is 1/3 million. To date, the tsunami in the Indian Ocean is recognized as the most destructive in the world.
The record holder for the amplitude of the waves was tsunami "Lituya" that happened in 1958. It swept across Lituya Bay in Alaska at a speed of 160 km/h. The cause of the world's highest tsunami was a gigantic landslide. The wave height reached 524 m.
What causes the appearance of most waves in the oceans and seas, about the destructive energy of the waves and about the most gigantic waves, and the largest tsunamis that man has ever seen.
The highest wave
Most often, waves are generated by wind: air moves the surface layers of the water column at a certain speed. Some waves can accelerate up to 95 km / h, while the wave can be up to 300 meters long, such waves travel huge distances across the ocean, but most often their kinetic energy is extinguished, consumed even before they reach land. If the wind subsides, then the waves become smaller and smoother.The formation of waves in the ocean is subject to certain patterns.
The height and length of the wave depends on the speed of the wind, on the duration of its impact, on the area covered by the wind. There is a correspondence: the highest wave height is one seventh of its length. For example, a strong breeze generates waves up to 3 meters high, an extensive hurricane - up to 20 meters on average. And these are already truly monstrous waves, with roaring foam caps and other special effects.
The highest ordinary wave of 34 meters was noted on the territory of the Agulhas Current (South Africa) in 1933 by sailors from the American ship Ramapo. Waves of this height are called "killer waves": in the gaps between them, even a large ship can easily get lost and die.
In theory, the height of normal waves can reach 60 meters, but these have not yet been recorded in practice.
In addition to the usual wind origin, there are other mechanisms of wave formation. The cause and epicenter of the birth of a wave can be an earthquake, a volcanic eruption, a sharp change in the coastline (landslides), human activity (for example, testing a nuclear weapon) and even a fall into the ocean of large celestial bodies - meteorites.
The biggest wave
This is a tsunami - a serial wave that is caused by some kind of powerful impulse. A feature of tsunami waves is that they are quite long, the distance between crests can reach tens of kilometers. Therefore, in the open ocean, a tsunami does not pose a particular danger, since the height of the waves is on average no more than a few centimeters, in record cases - a meter and a half, but the speed of their propagation is simply unthinkable, up to 800 km / h. From a ship on the high seas, they are not noticeable at all. The tsunami acquires destructive power when approaching the coast: reflection from the coast leads to compression of the wavelength, but the energy does not go anywhere. Accordingly, its (wave) amplitude, that is, the height, increases. It is easy to conclude that such waves can reach much higher heights than wind waves. 
The most terrible tsunamis occur due to significant disturbances in the relief of the seabed, for example, tectonic faults or shifts, due to which billions of tons of water begin to abruptly move tens of thousands of kilometers at the speed of a jet plane. Catastrophes occur when all this mass slows down on the shore, and its colossal energy first goes to increase the height, and eventually falls on land with all its might, a water wall.
The most "tsunami-prone" places are bays with high banks. These are real tsunami traps. And the worst thing is that a tsunami almost always comes suddenly: in appearance, the situation at sea can be indistinguishable from an ebb or flow, an ordinary storm, people do not have time or do not even think to evacuate, and suddenly they are overtaken by a giant wave. The warning system is little developed.
Territories with increased seismic activity are areas of special risk in our time. No wonder the name of this natural phenomenon is of Japanese origin.
The worst tsunami in Japan
The islands are regularly attacked by waves of various calibers, and among them there are truly gigantic, entailing human casualties. An earthquake off the east coast of Honshu in 2011 triggered a tsunami with a wave height of up to 40 meters. The earthquake is rated as the strongest in the recorded history of Japan. The waves hit the entire coast, together with the earthquake, they claimed the lives of more than 15 thousand people, many thousands went missing. 
Another highest wave in the history of Japan hit the west of Hokkaido in 1741 as a result of a volcanic eruption, its height is approximately 90 meters.
The biggest tsunami in the world
In 2004, on the islands of Sumatra and Java, the tsunami caused by a strong earthquake in the Indian Ocean turned into a massive disaster. Died, according to various sources, from 200 to 300 thousand people - a third of a million victims! To date, it is this tsunami that is considered the most destructive in history. 
And the record holder for the wave height is named "Lutoya". This tsunami, which swept through Lituya Bay in Alaska in 1958 at a speed of 160 km / h, was triggered by a giant landslide. The wave height was estimated at 524 meters.
Meanwhile, the sea is not always dangerous. There are "friendly" seas. For example, no river flows into the Red Sea, but it is the cleanest in the world. .
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Tsunamis have been a nightmare for the inhabitants of the islands for all ages. These multi-meter waves swept away everything in their path with tremendous destructive force, leaving behind only bare earth and debris. The statistics of monstrous waves has been conducted by scientists since the nineteenth century, during this period more than a hundred tsunamis of various power were recorded. Do you know what were the biggest tsunamis in the world?
Tsunami: what is it?
It is not surprising that the term "tsunami" was first introduced by the Japanese. They suffered from giant waves most often, because the Pacific Ocean gives rise to the largest number of destructive waves than all other seas and oceans combined. This is due to the peculiarities of the relief of the ocean floor and the high seismicity of the region. In Japanese, the word "tsunami" consists of two hieroglyphs meaning a bay and a wave. Thus, the very meaning of the phenomenon is revealed - a wave in the bay, sweeping away all life on the coast.
When was the first tsunami recorded?
Of course, tsunamis have always suffered. Ordinary island residents came up with their own names for the killer waves and believed that the gods of the seas punish people by sending destructive waves at them.
For the first time, a tsunami was officially recorded and explained at the end of the sixteenth century. This was done by a monk of the Jesuit church, Jose de Acosta, he was in Peru, when a wave about twenty-five meters high hit the shore. She swept away all the settlements around in a few seconds and advanced ten kilometers deep into the continent.
Tsunami: causes and consequences
Tsunamis are most often caused by earthquakes and underwater volcanic eruptions. The closer the epicenter of the earthquake is to the coast, the stronger the killer wave will be. The largest tsunamis in the world that were recorded by mankind could reach speeds of up to one hundred and sixty kilometers per hour and exceed three hundred meters in height. Such waves do not leave a chance to survive for any of the living beings that are on their way.
If we consider the nature of this phenomenon, then briefly it can be explained as the simultaneous displacement of a large amount of water masses. Eruptions or earthquakes raise the ocean floor sometimes by several meters, which causes water vibrations and forms several waves that diverge from the epicenter in different directions. Initially, they do not represent something terrible and deadly, but as they approach the coast, the speed and height of the wave increases, and it turns into a tsunami.
In some cases, tsunamis are formed as a result of giant landslides. During the twentieth century, about seven percent of all gigantic waves arose for this reason.
The consequences of the devastation left behind by the largest tsunamis in the world are terrible: thousands of human victims and hundreds of kilometers of land filled with debris and mud. In addition, in the disaster area, there is a high probability of the spread of infectious diseases due to the lack of drinking water and the decay of the bodies of the dead, the search for which is not always possible to organize in the shortest possible time.
Tsunami: is it possible to escape?
Unfortunately, the global tsunami warning system is still imperfect. At best, people learn about the danger a few minutes before the wave hits, so you need to know the signs of impending disaster and the rules for survival during a cataclysm.
If you are on the sea or ocean coast, then carefully follow the reports of earthquakes. A shaking of the earth's crust with a magnitude of about seven on the Richter scale that occurred somewhere nearby could serve as a warning of a possible tsunami strike. The approach of a killer wave gives out a sudden ebb - the ocean floor is quickly exposed for several kilometers. This is a clear sign of a tsunami. Moreover, the further the water goes, the stronger and more destructive the incoming wave will be. Animals often anticipate such natural disasters: a few hours before the cataclysm, they whine, hide, and try to go deep into the island or mainland.
To survive during a tsunami, you need to leave the dangerous area as soon as possible. Do not take a lot of things with you, drinking water, food and documents will be enough. Try to get as far away from the coast as possible or climb to the roof of a multi-storey building. All floors after the ninth are considered safe.
If the wave still overtakes you, then find an object that you can hold on to. According to statistics, most people die when the wave begins to return back to the ocean and takes away all the objects that have come across. Keep in mind that tsunamis almost never end in one wave. Most often, the first will be followed by a series of two or even three new ones.
So, when was the biggest tsunami in the world? And how much destruction did they bring?
This catastrophe does not fit any of the previously described incidents on the sea coast. To date, the Lituya Bay megatsunami has become the most gigantic and destructive in the world. Eminent luminaries in the field of oceanology and seismology are still arguing about the possibility of a repetition of such a nightmare.
Lituya Bay is located in Alaska and extends inland for eleven kilometers, its maximum width does not exceed three kilometers. Two glaciers descend into the bay, which became the unwitting creators of a huge wave. The 1958 tsunami in Alaska was caused by an earthquake on July 9th. The power of the shocks exceeded eight points, which caused a huge landslide to descend into the waters of the bay. Scientists calculated that thirty million cubic meters of ice and stones fell into the water in a few seconds. Parallel to the landslide, an under-ice lake sank thirty meters, from which the released water masses rushed into the bay.
A huge wave rushed to the coast and circled the bay several times. The height of the tsunami wave reached five hundred meters, the raging elements completely demolished the trees on the rocks along with the ground. At the moment, this wave is the highest in the history of mankind. The surprising fact is that only five people died as a result of a powerful tsunami. The fact is that there are no residential settlements in the bay; at the time the wave arrived in Lituya, there were only three fishing boats. One of them, together with the crew, immediately sank, and the other was raised by a wave to its maximum height and carried out into the ocean.
2004 Indian Ocean avalanche
The tsunami in Thailand in 2004 shocked all people on the planet. As a result of the destructive wave, more than two hundred thousand people died. The cause of the disaster was an earthquake in the Sumatra region on December 26, 2004. The tremors lasted no more than ten minutes and exceeded nine on the Richter scale.
A thirty-meter wave swept at great speed throughout the Indian Ocean and circled it, stopping near Peru. Almost all island states, including India, Indonesia, Sri Lanka and Somalia, suffered from the tsunami.
After killing several hundred thousand people, the 2004 Thailand tsunami left behind destroyed houses, hotels and several thousand local residents who died as a result of infections and poor-quality drinking water. At the moment, this tsunami is considered the largest in the twenty-first century.
Severo-Kurilsk: tsunami in the USSR
The list of "The biggest tsunamis in the world" should include the wave that hit the Kuriles in the middle of the last century. An earthquake in the Pacific Ocean caused a twenty-meter wave. The epicenter of the tremors of magnitude seven was located one hundred and thirty kilometers from the coast.
The first wave arrived in the city about an hour later, but most of the locals were in hiding on the high ground away from the city. No one warned them that a tsunami was a series of waves, so all the townspeople returned to their homes after the first one. A few hours later, the second and third waves hit Severo-Kurilsk. Their height reached eighteen meters, they almost completely destroyed the city. More than 2,000 people died as a result of the cataclysm.
Killer wave in Chile
In the second half of the last century, the inhabitants of Chile faced a terrifying tsunami, which killed more than three thousand people. The cause of the giant waves was the most powerful earthquake in the history of mankind, its magnitude exceeded nine and a half points.
A twenty-five-meter high wave covered Chile fifteen minutes after the first shocks. During the day, she covered several thousand kilometers, destroying the coast of Hawaii and Japan.
Despite the fact that humanity has been "familiar" with the tsunami for quite a long time, this natural phenomenon is still among the little-studied. Scientists have not learned how to predict the appearance of killer waves, therefore, most likely, in the future the list of their victims will be replenished with new deaths.
Megatsunami in Lituya Bay, Alaska, USA - the most destructive wave in the world (its length is more than 500 meters). The disaster occurred in 1958 on July 9. It was the largest natural disaster known to science. A little later, scientists called the phenomenon “megatsunami”.
Causes of the disaster
A giant wave is caused by an earthquake of 8 magnitudes off the Alaska Peninsula. The tremors caused a huge landslide that threw a massive glacier and piles of rocks into the water into Gilbert Bay. They became the main cause of the giant wave.
Consequences of the disaster
Large casualties were avoided: ten fishermen were killed and vegetation along the coast was destroyed. The recollections of eyewitnesses say that "the mountains trembled terribly, the stones rushed down rapidly, then suddenly they disappeared, and a giant wall of water appeared."
Presumably, similar tsunamis occurred here before with an interval of several decades. The tsunamis that occurred were also quite high, but the traces of their impact were finally eliminated by a natural disaster in 1958.
Next megatsunami
Megatsunami in Lituye was the first case for science when a giant wave was caused not only by an earthquake, but also by a landslide.
One of the strongest tsunamis was the aftermath of an earthquake in the Indian Ocean on December 26, 2004. This is the deadliest, natural disaster in modern history. The devastating wave dealt a huge blow to Thailand, Indonesia, Sri Lanka and Somalia. The capital of the Maldives, Male, was badly damaged during the tsunami. Parts of the city had to be rebuilt.
The death toll from the disaster is estimated at 235,000.
It is sad that many of the victims are tourists who spent their holidays on the shores of Thailand, Indonesia and Malaysia.
The largest wave in the world was recorded on July 9, 1958 in Alaska. Wave 524 meters high hit Lituya Bay.
A giant wave was formed as a result of an earthquake and the subsequent landslide. The power of the earthquake was 7.9 points, according to some sources 8.3 points (it was the strongest earthquake in the previous 50 years in this region). From a height of 1100 meters, 300 million cubic meters of rock, ice and stones fell on the bay. The speed of the resulting wave was 160 km / h, it practically destroyed the La Gaussi spit, which was in the path of the "giant", and the largest wave in the world uprooted trees.
At that time, there were three fishing ships in the bay, which were also destroyed. Luckily, the crews of the two ships managed to escape. 2 hours after the incident, not far from Lituya Bay, they were picked up by a rescue ship. However, the crew of the third vessel, consisting of two people, failed to escape, their bodies were never found.
In second place among the largest waves on Earth is 250 meter wave, formed on May 18, 1980 on the Spirit Lake (Spirit Lake) in the state of Washington (USA). The event began with an earthquake that collapsed part of the rock from the mountainside, as a result of which the heated liquid inside the volcano turned into steam and an explosion occurred, equal in power to 20 million tons of TNT.
In third place in the list of the most gigantic waves in the world, you can put 100 meters high wave, which was recorded in 1792 in Japan. It was formed as a result of the collapse of part of Mount Unzen (Unzen), the collapse occurred due to a powerful earthquake (6.4 points). A giant wave covered the nearby settlement. About 15 thousand people died.
Another tragedy associated with huge waves occurred on October 9, 1963 at the Vaiont dam in Italy (Belluno province). Big 90 meters high wave was formed as a result of the collapse of a huge stone massif with an area of 2 square meters in the reservoir. km. A giant wave went through the lower lying areas at a speed of about 10 m / s, washing away everything in its path. According to various sources, from 2 to 3 thousand people died, several settlements were completely destroyed.
According to many scientists, the largest waves in the world will not be formed as a result of earthquakes, but as a result of collapses of large mountain ranges on the coast or near water bodies. Scientists have already compiled a list of possible rock collapse areas and identify 4 main places:
1) Hawaiian Islands. Experts believe that landslides from local volcanoes could cause waves up to 1 kilometer high.
2) British Columbia (Canada). Some geologists believe that part of Mount Breckenridge could collapse into Harrison Lake, after which a large wave would form that could wash away the tourist town of Harrison Hot Springs (95 kilometers from Vancouver)
3) Canary Islands. The special attention of scientists (in particular, the English volcanologist William McGuire, the American seismologist Stephen Ward and others) is attracted by the island of La Palma with its chain of Cumbre Vieja volcanoes. Scientists say that as a result of the earthquake, a mountain mass with an area of 500 cubic kilometers could collapse, which could form the largest wave in the world with a height of more than 1 kilometer, which will spread in a westerly direction. Predominantly hit the east coast of South and North America. Upon reaching cities such as Boston, Miami, New York, etc. wave height can be from 20 to 50 meters.
4) Cape Verde Islands (Cape Verde). The local steep cliffs can also pose a great danger.
There is also an interesting and still little-studied phenomenon in the world called "Killer Waves". These are huge single waves, the height of which is from 20 to 34 meters. The first officially recorded case of the appearance of a killer wave occurred on the oil platform "Dropner" on January 1, 1995, off the Norwegian coast. Its height was 25.6 meters.
Interestingly, killer waves appear out of nowhere, unlike the same tsunamis, which are caused by landslides and earthquakes. It is believed that killer waves arise due to their transformation while moving across the ocean, as well as the features of their own dynamics.
A feature of the killer wave is also that it exerts much more pressure on the object (ship, oil platform, etc.). One sq. a meter of surface experiences a pressure of 100 tons, while an ordinary wave 12 meters high exerts a pressure of 12 tons. One can imagine what a killer wave could do to a ship, given that most ships can only carry 15 tons.
