How are quicksand formed? Coastal quicksand.

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Quicksand is a deadly attraction. The main danger is that they are almost impossible to distinguish from ordinary sandy areas. This means that if you are traveling, for example, through the desert, where there is often the same type of landscape without rocks and vegetation, then there is a possibility that at some point you will simply start to fall “underground.”

Quicksand: what is it?

Basically, quicksand is formed in places where underground springs appear or when groundwater approaches the soil. In addition, the condition for their appearance is the presence of sand without clay impurities with a grain diameter of up to 3 mm.

The smallest particles of moisture, mixing with such sand, do not allow air to pass through, and friction between grains of sand disappears. As a result, grains of sand turn into a semi-liquid mass, a swamp, which in appearance is almost impossible to distinguish from an ordinary desert or beach. This is a viscous mass with enormous counteracting force.

How to spot quicksand

It is difficult to visually detect classic quicksand - they can lie in wait for a traveler anywhere along the entire route. There is a journey that takes more than one day, and gradually attentiveness becomes dull, which leads to serious consequences.

Since quicksand is a viscous quagmire, it looks like a flat surface with small motionless ripples. That is, any flat area could potentially turn out to be an impassable swamp. It should be noted that the sand on the surface of the bog can dry out and sometimes even grass grows on it.

Most often, quicksand can be found along the banks of reservoirs and in the lowlands of hills - where underground sources are likely to reach the surface. To be on the safe side, you need to move slowly, be able to quickly get rid of your backpack and other cargo, and also test the road in front of you with a pole or stick.

In a normal, dry state, when poured from vessel to vessel (take an hourglass as an example), sand allows air to pass through. But if there is moisture between the grains of sand, air does not pass, and the sand does not spill out, blocking the passage. This property is the basis for the appearance of a bog.

This type of sand is characterized by enormous counterforce. If a person’s leg falls into quicksand, to free it it is necessary to expend the effort of a heavyweight weightlifter, and only on condition that his other leg has a reliable fulcrum and is on a hard surface.

In addition, the impact of a quagmire can be compared to a seat belt - the faster the trapped person moves, the more firmly the mire binds him. This occurs due to the instant “hardening” of quicksand due to the appearance of rarefied air under the released foot. The presence of a discharged space leads to the opposite effect - pulling the leg even deeper (“collapse”).

Quicksand against man

At its core, quicksand can be classified as a type of non-Newtonian fluid with a high content of small solids (sand grains). That is why a person, when he finds himself in such a place, begins to fall into it like into water. If at the same time he does not make sudden movements, then the dive will stop when the mass of displaced sand becomes equal to the mass of the person.

What to do if you find yourself in quicksand

There are certain rules of conduct when falling into quicksand. Following these rules will allow you to get out of the situation alive.

1. Don't panic! If you start twitching or making other sudden movements, you will go towards the core of the planet.
2. Fall backward, flat, preferably on your back - in general, take a horizontal position with your whole body.
3. Try to immediately discard everything unnecessary - backpack, tent, etc. Life is more important.

If you start making sudden movements, holes will appear that will continue suction. After the excitement calms down, move slowly, preferably back in the direction from which you came, since it is unknown how far ahead the dangerous sands extend.

Relax your body, imagine that you are lying on your back in the water and relaxing. When moving, the sand should flow gently under the body and on the sides. This process is labor-intensive, but effective. If your lower body does sink vertically into the sand, place your torso on the surface and slowly but forcefully release your legs.

Interesting and tragic facts about quicksand

Morecambe Bay, England. Known since the 15th century, when it was forbidden to go onto the sand during high tide. Every year it claimed the lives of up to 150 people. People caught in quicksand died during a 9-meter high tide that covered them headlong.

Goodwin Shoals, South Foreland, England. They consume ships, the remains of which rise above the sands. The place is known as the "Ship Graveyard". One day, the Goodwin shoals swallowed up the lighthouse tower.

Tarnagen Fjord, Alaska. The coast is about 80 km long and consists of quicksand.

Sable Island, Atlantic. Quicksand swallows entire ships after shipwrecks.

Jamaica, Port Royal. Completely drowned in quicksand in 1692. 2,000 townspeople died. After the earthquake, the soil hardened, so it was initially believed that the city was swallowed up by the “abyss of the sea.”

An example of American paratroopers falling into quicksand

Everyone has heard about quicksand, few have seen it, but only a few know what they are and what danger they pose. Quicksand can swallow an animal or a person in a few minutes, leaving no chance of salvation, and it turns out there have been cases when ships and even entire cities have disappeared in quicksand. Quicksand is a terrible and dangerous killer that humans are not yet able to fight, just like volcanic eruptions, tsunamis and earthquakes.

This natural phenomenon has a scientific explanation - it is the most ordinary sand, under a layer of which there is a source of water, making its way to the top. Imagine a picture: good weather, sandy shore, a person walking along the beach. It turns out that he is a few steps away from mortal danger: under a layer of sand at a depth of several hundred meters, an underground spring has formed, which makes its way up. Water begins to fill the space between the grains of sand, pushing them apart and reducing the cohesion between them. As a result, the sand becomes mobile and unstable.

The density of quicksand is greater than the density of water; their mixture turns into a very viscous substance, which gradually pulls the body down. It is impossible to swim in them, but moving slowly and smoothly is quite possible. This is the chance of salvation for a person who has fallen into quicksand - you can’t pull hard, wave your arms and legs, this leads to hardening of the sandy soil around. The correct behavior is to lie on your back, spread your arms wide and try to free your legs from the sand captivity. Then a person will have the opportunity to float on the surface of a quicksand swamp and wait for help from the outside.

The place where quicksand is hidden is quite difficult to distinguish from ordinary, solid soil. The sun usually dries the top layer of the furnace surface well, which leads to the formation of a thin, dry layer of soil on which grass begins to grow. This is how a natural trap is formed, into which any living creature can fall. Most often, quicksand can be found in the lowlands of hilly areas, on the banks of rivers and lakes.

There were quite a lot of such dangerous places in England, most of which are filled up these days. Morecambe Bay is notorious, where more than 150 people died over the years. During low tide, the sea in this area retreats far from the coastline, and the bottom quickly dries out, creating the illusion of safety. People walking on the dry surface are trapped by quicksand, and the fast tide, which rises to 9 meters, covers the unfortunate people completely.

To protect people from this danger, back in the 15th century, the English government introduced the position of a guide in this area, who was supposed to protect travelers from this treacherous place. Today, a special rescue service operates in the bay, whose task is to help the affected people. Every year they rescue about 30 people injured by quicksand.

A rescue service is also organized in Alaska to patrol the Tarnagen fjord, which is 80 kilometers long and consists entirely of quicksand. And Sable Island in the Atlantic Ocean is famous for the fact that entire ships that find themselves on land during a shipwreck perish in the quicksand there.

Another place where sands swallow ships is the South Foreland headland (England), where the Goodwin Shoals are located, world famous as the “ship graveyard”. There, on a vast sandbank, there are half-buried ships. In some places, among the gray-yellow sand, only the remains of masts and rusty pipes of former conquerors of the seas stick out. It's sad to see how ships live out their lives amid the sandy silence. The sands tenaciously hold onto their prey, and it is almost impossible to save the ship, and people do not always have time to leave the doomed ship.

One of the victims of the Goodwin Sands was the ship Gelena Modjeska, whose cargo was estimated at $3 million. On September 12, 1946, the ship ran aground off the southern tip of South Foreland Cape. For four days, eight rescue tugs tried to save the ship, but on the fifth day, the Helena Modjeska broke in half, and the cargo and ship fell victim to the sands. The captain could not survive the tragedy and on September 17 shot himself in a hotel room.

In 1954, quicksand in this place swallowed up a lighthouse that warned ships of danger. The tragedy happened so quickly that the arriving helicopter managed to save only one worker from the tower that had almost sunk into the sand. And there are many, many such stories about this disastrous place.

Ordinary sands become quicksand for another reason - as a result of an earthquake. When solid landmass briefly turn into quicksand, not only people and ships perish, but entire cities.

This is how the city of Port Royal in Jamaica perished in 1692. As a result of a major earthquake, most of it went under water and was swallowed up by the depths of the sea. This is what the experts of the time thought. After 300 years, modern scientists became interested in this tragedy and found out that the city did not go under water, but drowned in quicksand. After the earthquake, the soil hardened again and buried more than 2,000 city residents alive.

There is another scientific opinion about the origin of quicksand. Some scientists believe that not only water and seismic activity affect its mobility, but also electrical effects that lead to the formation of a positive charge between sand particles, which in turn leads to a decrease in friction between them. And if a person steps on such sand, he will fail.

Quicksand is another mystery of nature that still continues to excite the minds of scientists and interest extreme travelers. This natural phenomenon cannot yet be classified as an explainable natural phenomenon; it is possible that not all the secrets of quicksand have yet been revealed by man. Well, we can only wish travelers strong and reliable soil under their feet.

Without a doubt, quicksand is one of the most dangerous places on Earth. Usually the sun dries out the top layer of sand, resulting in a thin, hard crust on which grass can even grow. But the illusion of reliability will instantly evaporate, as soon as you step on it, the ground will literally float from under your feet. The poor souls who step on this sand, which seems like solid ground, are instantly sucked in. The legs become squeezed by a hardened mass, and it is impossible to pull them out without outside help.

Quicksand itself cannot kill a person. Firstly, it will not be able to completely absorb a person, since it is a non-Newtonian liquid. However, if a person is not saved in time, he may die from a number of other reasons. For example, from dehydration, solar radiation, various living creatures, or dying under the tide.

Many theories have been proposed about the quicksand phenomenon. Most of them, of course, turned out to be wrong. However, over time the situation began to become clearer. It turned out that the properties of wet sand depend significantly on the amount of water it contains. Moistened grains of sand easily stick together, demonstrating a sharp increase in adhesion forces, which in dry sand are caused only by surface unevenness and are therefore very small. The forces of surface tension of the films of water surrounding each grain of sand cause them to stick together. In order for sand grains to stick together well, water must cover the particles and their groups with a thin film, while most of the space between them must remain filled with air. If the amount of water in the sand is increased, then as soon as the entire space between the sand grains is filled with water, the surface tension forces disappear and the result is a mixture of sand and water that has completely different properties. Thus, Quicksand is the most ordinary sand, under the thickness of which at a depth of several meters there is a fairly strong source of water.

Why does a person fall into quicksand? It's all about the special structure of the grains of sand. The flow of water coming from below whips up a loose cushion of grains of sand, which is in relative equilibrium for some time. The weight of a traveler who wanders into such a place collapses the structure. The grains of sand, being redistributed, move along with the body of the victim, additionally as if sucking the poor fellow into the soil layer. After this, the structure of the sand around the unfortunate person becomes completely different - tightly pressed wet grains of sand form a trap due to the force of the surface tension of the water layer. When you try to pull your leg out, a vacuum of air is formed, pulling the leg back with enormous force. To pull your leg out in such a situation at a speed of 0.1 m/s, you need to apply a force equal to the force of lifting a medium-sized passenger car. So, if you get into quicksand, it is better not to make sudden movements, but try to lie on your back and, with your arms outstretched, wait for help.

“Do you know what quicksand is? They can suck you in, and it’s impossible to get out of them!”- we scared each other as children. For many, stories about quicksand have remained a childhood horror story. For a long time I myself believed that this was an invention of writers who wrote adventure novels. But this natural phenomenon actually exists. And today we will reveal everything to you "terrible secrets" of quicksand.

The nature of quicksand

Yes, quicksand exists. How are they formed? For sand to turn into a quicksand, it must be wet and, at the same time, supersaturated with air or other gas. This happens if there is enough sand underneath the sand layer. powerful rising water source. The stream whips up the loose sand cushion, like a mixer, moistening the sand and saturating it with air. As a result, the grains of sand stick together very strongly. This occurs due to the surface tension of water and the large amount of air space between them. To make it easier to understand, let’s give an example: if you remove air from quicksand, then it will be simple. If you remove water - . It is the presence of water and air in the sand that simultaneously makes it shifting.

The process of formation of quicksand in the coastal zone

Under the influence of gravity (i.e. when someone or something steps on quicksand) grains of sand begin to move faster, thereby “suck” the victim down. Simply put, you don’t just fail, but the sand also helps you through it. At the same time, wet grains of sand tightly grip your feet due to the same force of surface tension of water. When you try to free yourself, a rarefaction of air occurs, which forcefully pulls the trapped person back.

To get out of a quicksand trap, you need to exert an effort comparable to lifting a car. In this case, you will have to pull yourself by the hair, like Baron Munchausen. The prospect is depressing... However It is still possible to get out of the sand on your own. But how?

Death trap or test of endurance?

In fact It is impossible to drown in quicksand: its density is too high. Most often, people die in the sand from dehydration and sun exposure. (in deserts) or drown in sea waters during high tide because they do not have time to get out (tidal zone).

To get out of a quicksand trap you need to stop resisting it. (Note: This reminded me of a well-known psychological technique. Don’t like the situation? Stop resisting, and it will go away on its own.) Quicksand is, at its core, a Newtonian fluid. Any attempt at resistance is met with strong opposition. But if you completely relax, you can win over the sand. Very slowly and smoothly you need to try to lie on your back or stomach. Then just as slowly move to the edge of the quicksand swamp and gradually crawl out of it to freedom.

Where are quicksand found?

Most often this natural phenomenon occurs in the intertidal zone and in hilly deserts. In the first case, the sea waves “church”. During low tide, the top crust can dry out within a day and create the illusion of a wonderful sandy beach, which in fact turns out to be deadly. Such beaches are found in England (Goodwin Shoals), in Alaska (Tarnagen fjord), in Jamaica. Not only people, but also cars and ships become victims of such places.

Even technology can fall victim to quicksand...

In deserts, water flows can pass under layers of sand, inside limestone deposits. Some of them rush upward like underground fountains. And in the same way they “beat” sand, turning it into quicksand. Such areas are even more difficult to recognize: outwardly they may remain dry under the scorching desert sun and even become overgrown with grass. But as soon as you step on it, you are trapped. The Sahara Desert is most famous for such “surprises”, because... a large underground river flows underneath it.

Quicksand of the Sahara Desert

Quicksand can even occur along the banks of rivers and lakes. But most often their depth and scale are not so great, and they do not pose a danger.

Quicksand in the intertidal zone

Be careful! Quicksand!

Quicksand is a terrible and dangerous killer, with which man is not yet able to fight, just like with volcanic eruptions, tsunamis and earthquakes.

The named natural phenomenon has a scientific explanation - this is just regular sand, under the layer of which there was a source of water, making its way up. Imagine a picture: good weather, sandy shore, a person walking along the beach. It turns out that he is a few steps away from death: under a layer of sand at a depth of several hundred meters, an underground spring has formed, which makes its way up. Water begins to fill the space between the grains of sand, pushing them apart and reducing the cohesion between them. As a result, it becomes mobile and unsteady.

Ordinary sands become quicksand for another reason - as a result of an earthquake. When solid landmass briefly turn into quicksand, not only people and ships perish, but entire cities.

So he died in 1692 city of Port Royal in Jamaica. As a result of a major earthquake, most of it went under water and was swallowed up by the depths of the sea. This is what the experts of the time thought. After 300 years, modern scientists became interested in this tragedy and found out that the city did not go under water, but drowned in quicksand. After the earthquake, the soil hardened again and buried more than 2,000 city residents alive.

Photo: ru.wikipedia.org

Quicksand is another mystery of nature that still continues to excite the minds of scientists and interest extreme travelers. This natural phenomenon cannot yet be attributed to explainability; it is possible that not all the secrets of quicksand have yet been revealed by man. Well, we can only wish travelers strong and reliable soil under their feet.