The biggest wave in the world. Tsunami is a catastrophic natural phenomenon

In December 2004, a photo of the biggest wave in the world spread around all the publications of the world. On December 26, an earthquake occurred in Asia, which resulted in a tsunami wave that killed more than 235,000 people.

The media published photos of the destruction, assuring readers and viewers that there has never been a big wave in the world. But the journalists were cunning... Indeed, in terms of its destructive power, the tsunami of 2004 is one of the deadliest. But the magnitude (height) of this wave is quite modest: it did not much exceed 15 meters. History knows higher waves, about which one can say: “Yes, this is the biggest wave in the world!”

Waves-record holders

Where are the biggest waves

Scientists are sure that the highest waves are not caused by earthquakes (because of them, tsunamis are more often formed), but by ground collapses. That's why high waves are most often:

… And other killer waves

Not only giant waves are dangerous. There is a more terrible variety: single killer waves. They come from nowhere, their height rarely exceeds 15 meters. But the pressure that they exert on all the objects they meet exceeds 100 tons per centimeter (ordinary waves "press" with a force of only 12 tons). These waves are practically not studied. It is only known that she crumples oil rigs and ships like a sheet of ordinary paper.

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

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

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 aircraft. 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

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

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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Waves, their beauty, continuous movement and variability never cease to amaze a person.

It is important to understand that changes in the ocean occur every second, the waves in it are infinitely different and unique.

Successful surfing is impossible without understanding how waves appear and propagate, which changes their speed, strength, shape, height.

Let's first understand the terminology.

wave anatomy

The periodic oscillation of the waters about the equilibrium position is called a wave.

She has the following elements:

• sole- lower plane;
• crest(linden, from English lip - lip);
• front- crest line;
• pipe(tube/barrel) - the area where the ridge meets the sole;
• wall(wall) - the sloping part on which the surfer slides;
• shoulder- the area where the wall becomes flat;
• peak is the point of incidence of the wave;
• impact zone- a place where linden falls.

Due to the variability of the waves, it is extremely difficult to measure them. Fluctuations are evaluated by several parameters.

Height- the distance from the sole to the ridge. They measure it differently. In reports for surfers indicate the difference in the oscillation of weather buoys. Sometimes the height of the wave is indicated in " growth».

Since the athlete glides along the wave, bending over, 1 "height" is approximately 1.5 meters.

Length is the distance between adjacent ridges.

steepness is the ratio of height to wavelength.

Period– time between two waves in a group (set).

Causes and features of wave formation

Contrary to naive ideas, a sea or ocean wave is not formed from coastal winds. The most common waves form far out in the ocean.

The wind, blowing in one direction for a long time, shakes huge masses of water, sometimes the size of a multi-storey building. Large winds are formed in the zone of extremely low pressure, characteristic of an anticyclone.

In moderate winds, the surface of the ocean appears steep short waves- "sheep".

At the inception stage 2D waves, whose height does not exceed the length, run in parallel elongated rows of ridges. As the wind increases, the crests disappear, and the wavelength grows faster.

When the wave and wind speeds equalize, the growth of the crests stops. From that moment on, the speed, length and period of the waves increase, and their height and steepness decrease. Such long waves more suitable for.

With a growing storm, younger waves overlap older ones, the sea seems to be erratic. When it reaches a peak, the waves become as long as possible, with extended fronts. Wherein the length of the ridges can increase to hundreds of meters(record - up to 1 km).

Waves whose crest is several times the wavelength are called three-dimensional. Most often, three-dimensional waves consist of alternating "hills", "bumps" and "troughs". Waves come in sets (groups) of 2–10. Most often, 3. Usually medium wave- the highest and correct in the set.

What moves the wind

Any new wave raises, then lowers the water masses.

Interesting fact: water particles do not move horizontally, but in an irregularly shaped circle or ellipse perpendicular to the wave front.

In fact, the trajectory of the movement of water particles resembles loops: the intensive rotation of the "water wheel" is superimposed by a weak forward movement towards the wind.

This is how the profile of the wave is formed: its windward slope is gentle, and the leeward slope is steep.

Because of this, the ridges collapse, forming foam.

It is not the mass of water that moves during the wind, but the profile of the wave. So, lost by the surfer will swing back and forth, up and down, slowly moving towards the shore.

What sets the wave parameters

They depend on the speed, duration of the wind, changes in its direction; from the depth of the reservoir, the length of the wave acceleration.

Last determined by the size of the water area.

The action of the wind should be enough to cover the entire space.

That's why stable waves for are usually found on the ocean coast.

Changes in wind speed and direction more than 45 degrees, the old oscillations slow down, then a new wave system is formed.

Swells

Having reached the maximum size, the waves set off on a journey to the shores. They align: smaller ones are absorbed by large ones, slow ones are absorbed by fast ones.

An array of waves of the same size and power generated by a storm is called swell. The path of a swell to the shore can last thousands of kilometers.

Distinguish wind And bottom swells.

• First not suitable for surfing: in it the waves will not travel a long distance and will break already at great depths.
• Second- what you need, its long fast waves will go a long way and will be steeper when breaking.

Swells differ in amplitude and period. More period - better and smoother waves.

In Bali, waves with a period of less than 11 seconds are called wind swells. From 16 seconds - excellent waves, a period of 18 seconds - good luck, which surfers flock to catch.

For every spot the optimal direction of the swell is known, at which high-quality waves are formed.

Waves crashing

Moving towards the shore, while bumping into shallows, reefs, islands, the waves gradually waste their former power.

The longer the distance away from the center of the storm, the weaker they are.

When meeting with shallow water, rolling water masses have nowhere to go, they move up.

The period of the waves decreases, they seem to shrink, slow down, become shorter and steeper. This is how the surf wave grows.

Finally, the crests capsize, breaking or breaking the waves. The greater the depth difference, the steeper and higher the wave will be!

It occurs near reefs, rocks, shipwrecks, on a steep sandbar.

Ridge growth begins at a depth equal to half the height of the wave.

Wind directions

rise at dawn to
ride in calm water on smooth water - it's the perfect setting.

The quality of the waves depends on the coastal wind, some of the highest quality -.

1. Onshore- Wind blowing from the ocean.

He "blows off" the crests, crushes the waves, as a result they become tuberculate; doesn't let them get up.

Onshore forces the waves to close ahead of time. This worst for surf wind, it can ruin the whole skating.

It is dangerous when the directions of the wind and the swell coincide.

2. Offshore– wind from the shore towards the ocean.

If he does not fly in gusts, then he gives the waves the correct shape, “raises” them and pushes back the moment of collapse.

It's the wind perfect for surfing.

3. Crossshore- wind along the shore.

It does not improve sometimes spoils a lot wave front.

Wave types

closeout- a closed wave that breaks immediately along its entire length, therefore unsuitable for skiing.

gentle waves do not differ in speed and steepness. With a slight slope of the bottom, they break slowly without forming a high wall and pipe, therefore recommended for beginners.

Plunging waves- powerful, fast, high waves that occur with a sharp drop in depth. Create opportunities for tricks. They form inside the cavity - pipes that allow you to make passages inside.

Preferred for professionals, are dangerous for beginners - they fall more often.

Types of surf spots

The place where the wave rises is called surf spot. The nature of the wave is determined by the features of the seabed.

• Beach break- a place where the waves break on the sandy bottom. In a section with different depths, the wave bends and collapses towards the shallows. This creates an opportunity for the surfer to glide across the water wall.

Video

Watch a video about the conquest of a giant wave by a surfer:

Why does Nazar have the biggest waves in the world? July 15th, 2017

There is a place in the world from which photo and video reports about giant waves are often taken. For the past few years, records in Big Wave surfing for the largest wave taken (both by hand and with the help of a jet) have been set on the same Nazaré wave. The first such record was set by Hawaiian surfer Garrett McNamara in 2011 - the wave height was 24 meters. Then, in 2013, he broke his record by riding a wave 30 meters high.

Why exactly in this place are the biggest waves in the world?

Let's first recall the mechanism of wave formation:

So, it all starts far, far away in the ocean, where strong winds blow and storms rage. As we know from the school geography course, the wind blows from an area with high pressure to an area of ​​low pressure. In the ocean, these areas are separated by many kilometers, so the wind blows over a very large area of ​​the ocean, transferring some of its energy to the water through friction. Where it happens, the ocean is more like a bubbling soup - have you ever seen a storm at sea? It's about the same there, only the scale is larger. There are small and large waves, all mixed up, superimposed on each other. However, the energy of water also does not stand still, but moves in a certain direction.

Due to the fact that the ocean is very, very large, and waves of different sizes move at different speeds, during the time that all this seething porridge reaches the shore, it is “sifted”, some small waves add up to others into large ones, others, on the contrary, mutually are destroyed. As a result, what is called Groung Swell comes to the shore - smooth ridges of waves, divided into sets from three to nine with large intervals of calm between them.

However, not every swell is destined to become surfing waves. Although, it is more correct to say - not everywhere. In order for a wave to be caught, it must break in a certain way. Wave formation for surfing depends on the structure of the bottom in the coastal zone. The ocean is very deep, so the mass of water moves evenly, but as it approaches the coast, the depth begins to decrease, and the water that moves closer to the bottom, for lack of another way out, begins to rise to the surface, thereby raising waves. In the place where the depth, or rather shallowness, reaches a critical value, the rising wave can no longer become larger and collapses. The place where this happens is called the lineup, and that's where the surfers sit, waiting for the right wave.

The shape of the wave directly depends on the shape of the bottom: the sharper it becomes shallow, the sharper the wave. Usually the sharpest and even trumpeting waves are born where the height difference is almost instantaneous, for example, at the bottom of a huge stone or the beginning of a reef plateau.

Photo 2.

Where the drop is gradual and the bottom is sandy, the waves are gentler and slower. It is these waves that are best suited for learning to surf, so all surf schools conduct the first lessons for beginners on sandy beaches.

Photo 3.

Of course, there are other factors that affect the waves, for example, the same wind: it can improve or worsen the quality of the waves depending on the direction. In addition, there are so-called wind swells, these are waves that do not have time to “sift” with distance, since the storm rages not so far from the coast.

So, now about the highest waves. Thanks to the winds, huge energy is accumulated, which then moves towards the coast. As it approaches the coast, the oceanic swell transforms into waves, but unlike other places on our planet, a surprise awaits it off the coast of Portugal.

Photo 4.

The thing is that it is in the area of ​​​​the city of Nazare that the seabed is a huge canyon with a depth of 5000 meters and a length of 230 kilometers. This means that the oceanic swell does not undergo changes, but reaches, as it is, to the very continent, collapsing on the coastal rocks with all its might. Wave height is usually measured as the distance from the crest to the base (where, by the way, something like a trough is often sucked in, which increases the height compared to if measured by mean sea level at a given tide height).

Photo 5.

However, unlike such waves as Mavericks or Teahupu, on Nazar the ridge, even if it collapses, never hangs over the base, moreover, about 40 meters separate it from the bottom point along the horizontal axis. Due to spatial perspective distortion, when viewed from the front, we see a water block of 30 meters, technically, it is even larger, but this is not a wave height. That is, strictly speaking, Nazaré is not a wave, but a water mountain, a pure oceanic swell, powerful and unpredictable.

Photo 6.

However, the fact that Nazaré is not exactly a wave does not make this spot any less scary and dangerous. Garrett McNamara says that Nazar is incredibly difficult to pass. Usually three people help him in the water: one pulls him out on a jet to the lineup, accelerates him into a wave and does not swim far to make sure that everything is in order with the surfer. He is backed up by a second jet, as well as a third one a little further away, whose driver is watching all three. Also, Garrett's wife is standing on a rock near the lighthouse and tells him on the radio which waves are coming and which one can be taken. On the day he set his second record, not everything went smoothly. The first driver was knocked off the jet by a wave, so the second had to pull Garrett out of the foam, and the third hurried to help the first. Everything was done clearly and quickly, so no one was hurt.

Photo 7.

Garrett himself says the following: “Of course, all these safety nets and technical devices in surfing on big waves are a kind of cheating. And in principle, you can do without them, but in this case, the chances of dying are much higher. As for me personally, since I had a wife and children, I feel more responsibility for them and fear for my life, so I go to all technical tricks in order to most likely return home alive. ”

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