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 a “megatsunami.”

Causes of the disaster

The giant wave was caused by a magnitude 8 earthquake off the Alaska Peninsula. The tremors triggered a huge landslide that dumped a massive glacier and piles of rock into Gilbert Bay. They became the main reason for the emergence of a giant wave.

Consequences of the disaster

Major casualties were avoided: ten fishermen were killed and vegetation along the coast was destroyed. Eyewitness accounts say that “the mountains were shaking terribly, the stones were rapidly rushing down, then suddenly they disappeared, and a giant wall of water appeared.”

Presumably, similar tsunamis have occurred here before, with an interval of several decades. The tsunamis that occurred were also quite high, but their effects were finally eliminated by a natural disaster in 1958.

Next megatsunami

The Lituya megatsunami was the first time in science that a giant wave was caused not only by an earthquake, but also by a landslide.

One of the strongest tsunamis was the aftermath of the Indian Ocean earthquake on December 26, 2004. This is the deadliest, natural disaster in modern history. The destructive wave dealt a huge blow to Thailand, Indonesia, Sri Lanka and Somalia. The capital of the Maldives, Male, was very badly damaged during the tsunami. Certain areas of the city had to be rebuilt.

The death toll as a result of the natural disaster is estimated at 235 thousand people.

It is sad that many of the victims are tourists who spent their holidays on the shores of Thailand, Indonesia and Malaysia.

Tsunamis have been a nightmare for island residents throughout the centuries. These multi-meter waves with enormous destructive force swept away everything in their path, leaving behind only bare earth and debris. Scientists have been keeping statistics on monstrous waves since the nineteenth century; during this period, more than a hundred tsunamis of varying power were recorded. Do you know what the biggest tsunamis in the world were?

Tsunami: what is it?

It is not surprising that the term “tsunami” was first introduced by the Japanese. They suffered from giant waves more often than anyone, because the Pacific Ocean generates the largest number of destructive waves than all other seas and oceans combined. This is due to the topography of the ocean floor and the high seismicity of the region. In Japanese, the word "tsunami" consists of two characters meaning flood and 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, people have always suffered from tsunamis. Ordinary island residents came up with their own names for rogue waves and believed that the gods of the seas were punishing people by sending destructive waves at them.

The first tsunami was officially recorded and explained at the end of the sixteenth century. This was done by the monk of the Jesuit church, Jose de Acosta, he was in Peru when a wave about twenty-five meters high hit the shore. It swept away all the settlements around in a few seconds and moved ten kilometers deep into the continent.

Tsunami: causes and consequences

Tsunamis are most often caused by earthquakes and underwater volcanic eruptions. The closer the earthquake epicenter is to the coast, the stronger the rogue wave will be. The largest tsunamis in the world that have been 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 leave no chance of survival for any living creature caught in their path.

If we consider the nature of this phenomenon, then it can be briefly 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 diverging from the epicenter in different directions. Initially, they do not represent something terrible and deadly, but as they approach the shore, 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 destruction left behind by the world's largest tsunami are terrible: thousands of casualties 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 a lack of drinking water and rotting 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 warning system for a possible approaching tsunami is still imperfect. In the best case, people become aware of the danger a few minutes before the wave hits, so it is necessary to know the signs of impending trouble and the rules of survival during a cataclysm.

If you are on the sea or ocean coast, then carefully monitor earthquake reports. A shaking of the earth's crust with a magnitude of about seven on the Richter scale that occurred somewhere nearby can serve as a warning of a possible tsunami strike. The approach of a rogue wave is signaled by a sudden low tide - 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 arriving wave will be. Animals often anticipate such natural disasters: a few hours before the cataclysm, they whine, hide, and try to go deeper into the island or mainland.

To survive 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 move as far away from the coast as possible or climb onto the roof of a multi-story building. All floors after the ninth are considered safe.

If the wave does overtake 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 carries away all the objects it comes across. Keep in mind that a tsunami almost never ends in one wave. Most often, the first one will be followed by a series of two or even three new ones.

So, when were the biggest tsunamis in the world? And how much destruction did they cause?

This disaster does not fit any of the previously described incidents on the sea coast. To date, the megatsunami in Lituya Bay has become the largest and most destructive in the world. Until now, eminent luminaries in the field of oceanology and seismology are arguing about the possibility of repeating such a nightmare.

Lituya Bay is located in Alaska and extends eleven kilometers inland, 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 that occurred on July 9th. The power of the shocks exceeded eight points, which caused a huge landslide into the waters of the bay. Scientists estimate that thirty million cubic meters of ice and rocks fell into the water in a few seconds. Parallel to the landslide, the subglacial lake sank thirty meters, from which released water masses rushed into the bay.

A huge wave rushed onto 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 soil. This wave is currently the highest in human history. An amazing fact is that only five people died as a result of the 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, along with the crew, immediately sank, and the other was lifted by a wave to its maximum height and carried out into the ocean.

Indian Ocean avalanche 2004

The 2004 Thailand tsunami shocked everyone 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 points on the Richter scale.

A thirty-meter wave swept with great speed throughout the Indian Ocean and went around it, stopping near Peru. Almost all island countries were affected by the tsunami, including India, Indonesia, Sri Lanka and Somalia.

Having killed several hundred thousand people, the 2004 tsunami in Thailand left behind destroyed homes, 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 largest tsunamis in the world” must include the wave that hit the Kuril Islands in the middle of the last century. An earthquake in the Pacific Ocean caused a twenty-meter wave. The epicenter of the earthquake with a magnitude of seven was located one hundred and thirty kilometers from the coast.

The first wave arrived in the city about an hour later, but most local residents were in shelter on higher 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 two thousand people died as a result of the cataclysm.

Rogue wave in Chile

In the second half of the last century, Chileans faced a terrifying tsunami that 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 wave twenty-five meters high covered Chile fifteen minutes after the first shocks. In one day, it traveled several thousand kilometers, destroying the coasts of Hawaii and Japan.

Despite the fact that humanity has been “familiar” with tsunamis for quite some time, this natural phenomenon is still poorly understood. Scientists have not learned to predict the appearance of rogue waves, so, most likely, in the future the list of their victims will be replenished with new deaths.

At the end of December 2004, one of the most powerful earthquakes in the last half century occurred near the island of Sumatra, located in the Indian Ocean. Its consequences turned out to be catastrophic: due to the displacement of lithospheric plates, a huge fault was formed, and a large amount of water rose from the ocean floor, which, at a speed reaching one kilometer per hour, began to rapidly move throughout the Indian Ocean.

As a result, thirteen countries were affected, about a million people were left without a roof over their heads, and more than two hundred thousand were killed or missing. This disaster turned out to be the worst in human history.

Tsunamis are long and high waves that appear as a result of a sharp displacement of lithospheric plates of the ocean floor during underwater or coastal earthquakes (the length of the shaft is from 150 to 300 km). Unlike ordinary waves that appear as a result of the impact of a strong wind on the water surface (for example, a storm), a tsunami wave affects water from the bottom to the surface of the ocean, which is why even low-level water can often lead to disasters.

It is interesting that for ships located in the ocean at this time, these waves are not dangerous: most of the disturbed water is located in its depths, the depth of which is several kilometers - and therefore the height of the waves above the surface of the water ranges from 0.1 to 5 meters. Approaching the coast, the back of the wave catches up with the front, which at this time slows down slightly, grows to a height of 10 to 50 meters (the deeper the ocean, the larger the swell) and a crest appears on it.

It should be taken into account that the approaching shaft develops the highest speed in the Pacific Ocean (it ranges from 650 to 800 km/h). As for the average speed of most waves, it ranges from 400 to 500 km/h, but there have been cases when they accelerated to speeds of a thousand kilometers (the speed usually increases after the wave passes over a deep-sea trench).

Before hitting the coast, the water suddenly and quickly moves away from the shoreline, exposing the bottom (the further it recedes, the higher the wave will be). If people do not know about the approaching disaster, instead of going as far from the shore as possible, they run to collect shells or pick up fish that did not have time to go to sea. And just a few minutes later, a wave that arrived here at enormous speed does not leave them the slightest chance of salvation.

It must be taken into account that if a wave rolls onto the coast from the opposite side of the ocean, the water does not always recede.

Ultimately, a huge mass of water floods the entire coastline and goes inland to a distance of 2 to 4 km, destroying buildings, roads, piers and leading to the death of people and animals. In front of the shaft, clearing the way for the water, there is always an air shock wave, which literally explodes buildings and structures that are in its path.

It is interesting that this deadly natural phenomenon consists of several waves, and the first wave is far from the largest: it only wets the coast, reducing the resistance for the following waves, which often do not arrive immediately, and at intervals of two to three hours. The fatal mistake of people is their return to the shore after the first attack of the elements has left.

Reasons for education

One of the main reasons for the displacement of lithospheric plates (in 85% of cases) is underwater earthquakes, during which one part of the bottom rises and the other sinks. As a result, the ocean surface begins to oscillate vertically, trying to return to the initial level, forming waves. It is worth noting that underwater earthquakes do not always lead to the formation of a tsunami: only those where the source is located a short distance from the ocean floor, and the shaking was at least seven points.

The reasons for the formation of a tsunami are quite different. The main ones include underwater landslides, which, depending on the steepness of the continental slope, are capable of covering enormous distances - from 4 to 11 km strictly vertically (depending on the depth of the ocean or gorge) and up to 2.5 km if the surface is slightly inclined.

Large waves can be caused by huge objects falling into the water - rocks or blocks of ice. Thus, the largest tsunami in the world, the height of which exceeded five hundred meters, was recorded in Alaska, in the state of Lituya, when, as a result of a strong earthquake, a landslide came down from the mountains - and 30 million cubic meters of stones and ice fell into the bay.

The main causes of tsunamis also include volcanic eruptions (about 5%). During strong volcanic explosions, waves are formed, and water instantly fills the vacated space inside the volcano, as a result of which a huge shaft is formed and begins its journey.

For example, during the eruption of the Indonesian volcano Krakatau at the end of the 19th century. The “rogue wave” destroyed about 5 thousand ships and caused the death of 36 thousand people.

In addition to the above, experts identify two more possible causes of the tsunami. First of all, this is human activity. For example, in the middle of the last century, the Americans carried out an underwater atomic explosion at a depth of sixty meters, causing a wave about 29 meters high, although it did not last long and fell, having covered a maximum of 300 meters.

Another reason for the formation of a tsunami is the fall of meteorites with a diameter of more than 1 km into the ocean (the impact of which is strong enough to cause a natural disaster). According to one version of scientists, several thousand years ago it was meteorites that caused the strongest waves that became the causes of the largest climate disasters in the history of our planet.

Classification

When classifying tsunamis, scientists take into account a sufficient number of factors of their occurrence, including meteorological disasters, explosions and even ebbs and flows, and low wave surges with a height of about 10 cm are included in the list.
By shaft strength

The strength of the shaft is measured by taking into account its maximum height, as well as how catastrophic the consequences it caused and, according to the international IIDA scale, there are 15 categories, from -5 to +10 (the more victims, the higher the category).

By intensity

According to intensity, “rogue waves” are divided into six points, which make it possible to characterize the consequences of the disaster:

1. Waves with a category of one point are so small that they are recorded only by instruments (most people do not even know about their presence).
2. Two-point waves are capable of slightly flooding the shore, so only specialists can distinguish them from the fluctuations of ordinary waves.
3. The waves, which are classified as force three, are strong enough to throw small boats onto the coast.
4. Force four waves can not only wash large sea vessels ashore, but also throw them onto the coast.
5. Point five waves are already acquiring catastrophe proportions. They are capable of destroying low buildings, wooden buildings, and causing casualties.
6. As for force six waves, the waves that wash up on the coast completely devastate it along with the adjacent lands.

By number of victims

Based on the number of deaths, five groups of this dangerous phenomenon are distinguished. The first includes situations where no deaths were recorded. The second - waves that resulted in the death of up to fifty people. Shafts belonging to the third category cause the death of fifty to one hundred people. The fourth category includes “rogue waves,” which killed from one hundred to a thousand people.

The consequences of a tsunami belonging to the fifth category are catastrophic, since they entail the death of more than a thousand people. Typically, such disasters are typical for the waters of the deepest ocean in the world, the Pacific, but they often occur in other parts of the planet. This applies to the disasters of 2004 near Indonesia and 2011 in Japan (25 thousand dead). “Rogue waves” have also been recorded in history in Europe, for example, in the middle of the 18th century, a thirty-meter wave hit the coast of Portugal (during this disaster, from 30 to 60 thousand people died).

Economic damage

As for the economic damage, it is measured in American dollars and calculated taking into account the costs that must be allocated for the restoration of the destroyed infrastructure (lost property and destroyed houses are not taken into account, because they relate to the country’s social expenses).

Economists distinguish five groups based on the size of losses. The first category includes waves that did not cause much harm, the second - with losses of up to 1 million dollars, the third - up to 5 million dollars, and the fourth - up to 25 million dollars.

Damage from waves, classified as group five, exceeds 25 million. For example, losses from two major natural disasters, which occurred in 2004 near Indonesia and in 2011 in Japan, amounted to about 250 billion dollars. It is also worth taking into account the environmental factor, since the waves, which led to the death of 25 thousand people, damaged a nuclear power plant in Japan, causing an accident.

Disaster recognition systems

Unfortunately, rogue waves often appear so unexpectedly and move at such high speeds that it is extremely difficult to determine their appearance, and therefore seismologists often fail to cope with the task assigned to them.

Basically, disaster warning systems are built on the processing of seismic data: if there is a suspicion that an earthquake will have a magnitude of more than seven points, and its source will be located on the ocean (sea) floor, then all countries that are at risk receive warnings of approaching huge waves.

Unfortunately, the 2004 disaster occurred because almost all surrounding countries did not have an identification system. Despite the fact that about seven hours passed between the earthquake and the surging shaft, the population was not warned of the approaching disaster.

To determine the presence of dangerous waves in the open ocean, scientists use special hydrostatic pressure sensors that transmit data to a satellite, which allows them to quite accurately determine the time of their arrival at a particular point.

How to survive during a disaster

If it so happens that you find yourself in an area where there is a high probability of deadly waves occurring, you must remember to follow the forecasts of seismologists and remember all the warning signals of an approaching disaster. It is also necessary to find out the boundaries of the most dangerous zones and the shortest roads along which you can leave the dangerous territory.

When you hear a signal warning of approaching water, you should immediately leave the danger area. Experts will not be able to say exactly how much time there is to evacuate: it could be a couple of minutes or several hours. If you do not have time to leave the area and live in a multi-story building, then you need to go up to the top floors, closing all the windows and doors.

But if you are in a one- or two-story house, you need to immediately leave it and run to a tall building or climb some hill (as a last resort, you can climb a tree and cling tightly to it). If it so happens that you did not have time to leave a dangerous place and found yourself in the water, you need to try to free yourself from shoes and wet clothes and try to cling to floating objects.

When the first wave subsides, it is necessary to leave the dangerous area, since the next one will most likely come after it. You can return only when there are no waves for about three to four hours. Once at home, check the walls and ceilings for cracks, gas leaks and electrical conditions.

Ocean, sand, beach, cocktail, sun lounger and waves 30 meters high. Yes, it's all in one place, but, fortunately, at different times. How can this be? We head to the town of Nazare on the west coast of Portugal. It is here, on the shores of the Atlantic Ocean, that you can see both a relaxed beach holiday and the biggest waves in the world.

This landmark of Portugal is located between the capital Lisbon and the city of Porto.

In summer, the small resort town of Nazaré, with a population of about 15,000 people, is the country's classic tourist destination. Its long sandy beaches are occupied by tourists from all over the planet. They bask in the gentle sun and swim in the Atlantic Ocean. In general, an ordinary relaxing holiday.

In winter, everything changes dramatically. Beach tourists are replaced by extreme sports enthusiasts and lovers of unusual natural phenomena. During this period, one can observe the formation of giant waves that hit the coast almost at arm's length. This phenomenon, incredible in its power and amazing in its beauty, attracts both travelers and the most desperate surfers.

Who produces the biggest waves on the planet

Let us remind you once again that almost everything amazing, beautiful, sometimes frightening, but fascinating on our planet is produced by nature. In this case, the creator of the giant waves was the atypical topography of the ocean floor near the city of Nazaré, in particular the underwater Northern Canyon of Nazaré. This depression in the bottom surface reaches almost to the very shore, forming a kind of springboard for ocean waves.

It should be noted that the Nazaré Canyon is recognized as the deepest in Europe and one of the deepest in the world. It is located not parallel to the coast, but perpendicular. Its length is 227 km, and its depth reaches 5 kilometers (this is almost half the depth of the Mariana Trench). As you approach the coast, the depth decreases sharply, creating a barrier in the path of the wave and increasing its height many times over. Conditions arise under which colossal masses of water must jump over this obstacle. Don't forget, all this happens in close proximity to tourists.

In the pictures below you can see the geological reasons for the appearance of huge waves.

Typical diagram of the formation of a giant wave

But that's not all. The bottom topography alone is not enough to produce the highest waves. This requires a combination of many factors.

Hell of a cocktail for the biggest waves

The presence of the canyon creates special conditions for the creation of large waves. It splits the wave into two parts. One part increases its speed while passing through the canyon, and the second reunites with the first at the exit of the canyon into one large wave.

Opposing ocean current coming from the beach can add a few more meters.

For the birth of a giant wave, the wave period is important, which should be about 14 seconds. The wind, oddly enough, should be weak. The direction of the wave is very important; ideally it should come from the west or northwest. Added to these factors are storms in the northern part of the Atlantic that occur during the fall and winter. The combination of these factors can increase the average ocean wave several times.

How often do big waves appear?

Looking at the photos on the Internet, as well as on our website, you might think that giant waves in Nazaré are formed almost every minute. But that's not true. A little higher, you learned how many combined phenomena are required to produce a huge wave. This doesn't happen that often.

The Big Waves season in Nazaré occurs from October to February. During these months there are usually between 1 and 6 giant waves and tens or hundreds of much smaller waves. If you want to see a truly huge wave, then plan to spend at least 2 weeks here, or keep an eye on the forecasts on surfing websites. For a large wave, the forecast should indicate a wave size of more than 3 meters, a wave period of more than 13 seconds and a slight northerly wind.

If you are already there, check the sea conditions in real time through the online forecast and webcams. But, even if all forecasts indicate ideal conditions for the occurrence of large waves, then everything can change in just an hour and ruin a day with a favorable forecast.

But in Peru you can see the longest sea waves in the world. They are much safer than the waves in Nazaré, and you can ride them for up to several minutes at a time, traveling hundreds of meters on the crest of one wave

The story of conquering the giant waves of Nazaré

There are people in the world who “don’t feed them honey,” just let them conquer the biggest waves. They are usually called surfers. They, probably, with the advent of boards, began to collect the best places on the planet for their hobby. They did not ignore the waves near the city of Nazaré. Surfers were first noticed here back in the 60s of the last century. Since then they have been frequent guests here. But there is no data on conquering huge waves. Only in November 2011 did the world learn about the taking of the largest wave. Then Gareth McNamara, a surfer from Hawaii, conquered a wave 24 meters high. The brave comrade did not calm down and in January 2013 he broke his own record, taking on a 30-meter wave.

Gareth was the first to describe the sensations of such adventures. This proved incredibly difficult due to the unpredictability of wave behavior.

In this event, McNamara involved three assistants and one wife (his own). At the moment of wave formation, the first assistant on a jet ski tries to pull the surfer as high as possible onto the crest, and stays close to him for safety. Look at the photo of these waves, and you will understand that it is impossible to swim to them under your own power.

The second assistant runs a little further away and insures both of them. The third one keeps an eye on everyone else. And from the shore, a gray-haired wife watches everything and gives instructions to her husband on how best to catch the wave.

The first time everything went fine and no help was needed, but the second time proved the effectiveness of triple insurance. Then the first assistant was washed away from the jet ski by a wave, and the second assistant pulled out the surfer, and the third assistant pulled out the first one.

The danger of such adventures is extremely high, so surfers try not to climb waves 30 meters high unless absolutely necessary. They do it just for the records.

In October 2013, Brazilian surfer Carlos Berl rode a wave that was even bigger. But there is no absolutely accurate data on the height of the waves conquered, since it is quite problematic to take measurements.

Annual surf meeting in Nazaré

Despite the danger of such large waves, since 2016 a meeting or competition of surfers, the Nazare Challenge - WSL Big Wave Tour, managed by the World Surf League, has been taking place in Nazar. This competition brings together the best surfers from all over the world and lasts only one day. Moreover, it does not have a fixed date. It all depends on forecast sea conditions. The period of holding, or better to say waiting, is from October 15 to February 28. The day of the competition is confirmed 3 days before it takes place. This is the best that can be achieved with modern sea and wind forecasting technology.

This is a significant event for surfers. This is how one of the participants describes it:
“What followed after the starting signal was a dizzying, wild and unprecedented display of courage, stupidity and skill.”

Where is the best place to watch the biggest waves?

The best way to watch a giant wave is to stand on its crest on a surfboard. Any surfer will say that. Well, for ordinary tourists it is best to do this from Cape Nazaré, on which the lighthouse is located. Since the place is very interesting, you are unlikely to get lost. Fort San Miguel Arcanjo is also located here. You can also walk down to the sand on the beach via a dirt road, but be very careful. During the Big Wave season this is very dangerous.

Nowadays, in addition to the big waves, the attraction of Nazaré is the surfers who “ride” them. This, by the way, gives a good idea of ​​the size of the waves. When you see a little man running away from a huge multi-ton wave, you can imagine how large and powerful not only the Russian language is, but also the Atlantic Ocean.

1. As a rule, many famous surf spots have bottom topography similar to that near Nazaré, but on a smaller scale. The most famous are Teahupoo in Tahiti, Banzai Pipeline in Hawaii and Maverick’s Beach off the coast of California.
2. Local fishermen have long been afraid of this place. Several shipwrecks have occurred here. At the bottom of the canyon there is a sunken German submarine from World War II.