Quicksand. Description. Deadly dangerous. Cases. Quicksand: what a natural phenomenon

home Nature is terrible in her anger. Its arsenal includes rivers of boiling lava, giant tsunami waves, destructive earthquakes , bottomless swamps of swamps, floods. There's one more thing terrible weapon

. These are quicksands, which have long been called “dry swamps”.

Legends of Quicksand

They frighten children and travelers; they are told by old people instead of bedtime stories. Only unlike fictional stories, quicksand is a terrible reality that people living on the coasts most often encounter. Imagine: a storm, a ship in distress, desperate people. And suddenly in the distance there is a shore - hope for salvation. With great difficulty, the ship docks, but the cries of “Hurray” are replaced by cries of horror. The ship begins to slowly sink into the coastal sand. People are trying to escape, but, alas, few succeed.

Such cases, although they were not rare, were still almost all counted. But the number of people who disappeared during walks cannot be counted at all. The sand underfoot suddenly turns into a trap, the person panics, begins to flounder and drowns.

This is the town of Arnside, located on the coast of Morecambe Bay. The length of the strip of quicksand is 80 (!) meters - a giant trap.

This is the Goodwin Shoals on the South Foreland Cape. The second name is “Ship Graveyard”. It looks terrifying: the skeletons and sides, randomly scattered along the coast, are covered with sand. In other places you can only see the tip of the mast. A grim sight.
Alaska

This is the Tarnagen fjord.
Jamaica

This is the place where the city of Port Royal once stood, which disappeared in the 17th century. The original version is that there was an earthquake in 1692. The impact of the elements was powerful, a tidal wave destroyed the city, and the sea swallowed it. In 1992, scientists were able to prove that the city really drowned, but not in the water. He is another victim of the quicksand.

Caribbean Islands
Coast of Canada In principle, quicksand can be found anywhere there is water, sand and rocks. That is, the shores of lakes and seas, as well as big rivers

. On the outskirts of deserts, you can also fall into a trap created by quicksand.

If you remember your school physics lessons, you can easily find the answer to the formation of quicksand. The phenomenon of this phenomenon lies in the ratio of the amount of sand and water, as well as their interaction. What does dry (and therefore safe) sand consist of? From countless grains of sand and air. What happens if you add water here? The water will begin to envelop each grain of sand, and a film will form around it. Since the grains of sand have tiny particles dust, then the cementing process begins, in which they take an active part. This is how a completely new substance is formed - viscous and very viscous.

This means that for ordinary sand to turn into quicksand, it needs to be wet.. A bucket of water will not help, you need a constant source of water, and the larger it is, the greater the danger. In coastal places it is a tidal wave. The rest have underground springs. The depth of the source varies. If the mass of sand is large, then the estimated depth can reach forty meters. Moreover, only water sources that are in an almost vertical position or slightly inclined are suitable for creating fluidity. On the surface everything looks quite harmless: sand, pebbles here and there, a couple of bushes. Without special instruments, it is impossible to determine whether there is water in this place, whether the sand is wet, and what the extent of the danger is.

And the water works at this time, constantly wetting the layers of sand, causing it to crumble. This process is invisible from above; even specialists cannot determine it. But as soon as any heavy object gets here, the trap is triggered. The process of suction begins, being pulled deeper.

How to check if there is quicksand in this place?

It's better not to do this. Don't know the area? Avoid the sand that is pleasant to your bare feet. This measure is desirable everywhere and mandatory for those places where the trap has been triggered at least once. There is usually a rescue service and warning signs in these areas.

Is there a chance to get out of quicksand?

The answer is clear - yes. And now a big BUT. Only those who know what and how to do and do not get confused have a chance, that is, they will be able not to panic.

The actions are simple: lie on your back, try to spread your arms and legs, that is, occupy as much position as possible more space. If you squeeze into a ball, the weight will put pressure on one place, and the body will begin to sink faster. Usually both legs fall into the trap first, sometimes one gets stuck - this can be considered real luck. Lying on your back, with your arms outstretched, you need to slowly, without sudden movements, pull out your legs. The process may take an hour, but be patient and persistent - your life is worth it. After you free your legs, you need to determine where you came from. There, on that side, is a safe, hard surface. That's where you row, and in the literal sense of the word. Swim on the sand, preferably on your back. You can not? Carefully roll over onto your stomach and, pushing off with your arms and legs, “swim.” And remember: any sudden movement and you will be pulled into the sand.

Quicksand- a unique phenomenon, like all other inventions of Nature.

It should be said right away that the widespread belief that quicksand can swallow a person upside down is an exaggeration. However, they are really dangerous because it is very difficult to free yourself without outside help. People trapped in sand died from dehydration, sunburn, drowned during high tides because they were not rescued in time.

How quicksand is formed

It is absolutely impossible to simply determine by eye that the place in front of you is mortally dangerous. The sun dries out the top layer of sand, sometimes even some vegetation appears on it. It seems that this is the most ordinary sand. Strictly speaking, this is what it is - ordinary, only very small, similar to dust.

The main thing in the occurrence of the phenomenon is that the properties of dry and wet sand are different and strongly depend on how much water it contains. Dry sand is free-flowing, since the adhesion forces between individual grains of sand are provided only by the unevenness of their surfaces. If the sand is moistened, the adhesion forces will increase many times over. Water covers the grains of sand with a thin film, the surface tension forces of which cause them to stick together. In this case, a significant part of the space between individual grains of sand remains filled with air.

If water fills the space between the sand grains completely, surface tension forces cease to act. A fluid and viscous water-sand mixture is formed. As a matter of fact, the unique properties of quicksand - the ability to quickly “suck in” its victims and then hold them literally in stone captivity - are explained precisely by its high humidity.

Why does quicksand suck?

Sand becomes quicksand if there is a fairly powerful underground source underneath it. The flow of water moving from bottom to top “whips up” the sandy surface above it. Mutual arrangement grains of sand become unstable, but still remain. If a person steps on such a surface, the entire structure will collapse under his weight.

Grains of sand move along with the body of a failed person. The structure of the sand mass changes. Now the grains of sand are tightly pressed against each other, and the surface tension forces of the water film form a reinforced concrete frame around his feet. Since there is no air between the grains of sand, any movement creates a rarefied space. Raw sand, which has a high viscosity, does not have time to fill the cavities formed during movement, and the force atmospheric pressure strives to return the moving body back. It feels like the sand is sucking you in.

Scientists believe that another reason for the formation of quicksand is static charges resulting from the friction of sand grains. Since they are all of the same name, the cohesion between the grains of sand is weakened.

Quicksand is sand that is oversaturated with water from rising sources; as a result, they are capable of sucking in objects, animals and humans that fall on them. Quicksand is diverse in nature. Due to the thin film of water that envelops the grains of sand, the adhesion between them sharply decreases, and these sands behave almost the same as a liquid: the foreign body continues to sink until the weight of the sand it displaces is equal to the weight of the body itself.

The rate of suction depends on the structure of the sand, the mass and volume of the foreign object and can range from several minutes to several months.

terrible danger

There are many legends and dark stories associated with these sands. The terrible danger lurking beneath the surface of the sand seems so harmless at first glance.

Tarnagen Fjord in Alaska is pretty a nice place, in 1988, two tourists, the Dixon couple, decided to take a ride along the coast at low tide. The car got stuck in the sand. Adrianna Dixon got out of the car and immediately sank into knee-deep sand. The husband tried to help his wife for several hours, but was unable to free her from the trap. The sand was compressed and held the feet like cement. The husband called the rescue team, but the tide had already begun in the fjord. It was not possible to save the woman from sand captivity - the unfortunate woman drowned.

The action of quicksand (how it happens)

Why do people fall into quicksand? It's all about the special structure of the grains of sand. The water flow coming from below whips up a loose cushion of grains of sand, which remains in comparative equilibrium for some time. The weight of a traveler who finds himself in such a place collapses the structure. The grains of sand, being redistributed, begin to move along with the body of the unfortunate person, additionally as if sucking the victim into the layer of soil. After which, the structure of the sand around the victim completely changes - tightly pressed wet grains of sand form a trap due to the force of the surface tension of the water layer.

When trying to pull the leg out, a vacuum of air is formed, which pulls the leg back with enormous force. To pull your leg out similar situation at a speed of 0.1 m/s, it is necessary to apply a force equal to the lifting force of a medium-sized car. So, if you get into quicksand, it is advised not to make sudden movements, but to try to lie on your back and, with your arms outstretched, wait for help.

The nature of quicksand

To this day, scientists have not been able to fully understand the nature of this dangerous phenomenon. Some researchers believe that suction abilities are determined by the special shape of sand grains. According to one of the versions proposed by Russian physicist V. Frolov, the mechanism of action of quicksand is due to electrical effects, as a result of which the friction between sand grains becomes significantly less and the sand becomes fluid. If the fluidity extends to a depth of several meters, the soil becomes viscous and sucks in any massive body that ends up on it.

Geologist George Clark from the University of Kansas (America) spent many years researching the unique phenomena of sand and came to the conclusion that quicksand is ordinary sand that is mixed with water and has some properties of a liquid medium. According to Clark, volatility is not a natural phenomenon, but the special state of the sand. The latter occurs, for example, on a surface periodically flooded by the tide, or if there is a flow under a mass of sand. underground river.

Typically, quicksand is located in hilly areas where underground water flows often change direction and can rise to the surface or go deeper. When the water flow rises, this does not appear outwardly, although the surface of the earth suddenly becomes very dangerous.

Why you can get out of dry sand

With dry sand, everything is different: even a person buried up to his neck can gradually get out of it on his own, because when moving slowly on free place First, air enters, and then grains of sand begin to fill the niche. There is no such air in quicksand, and the suspension in its consistency can be compared to jelly, and the slowly moving mass will not have time to fill the resulting cavity, forming a vacuum.

There are two types of quicksand

1. With a wet surface. Can be found on the shores of lakes, rivers, seas, where rising springs are often present. There may be a thin crust of silt on top, formed from a fine fraction of sand.

2. With a dry surface. They are found in desert and rocky areas.

In English sea ​​coasts

Most of the legends about quicksand originated in Britain on the sea coasts, where for centuries there were dangerous areas that would suck in a person or animal who carelessly stepped onto the deceptive surface.

Excerpt from W. Collins’s novel “The Moonstone”:

“Between the two rocks lies the worst quicksand on the whole Yorkshire coast. During the ebb and flow of the tide, something happens in their depths, causing the entire surface of the sands to fluctuate in the most unusual way... Secluded and scary place!.. Not a single boat dares to enter this bay... Even birds fly away from the quicksand. The tide began to rise, and the terrible sand began to tremble. Its brown mass slowly rose, and then it all began to tremble...”

Back in the 19th century most such dangerous places in England they were buried and destroyed. There are currently no quicksands in densely populated areas.

Happy Rescue

1999 - Arnside (England), in front of his parents' eyes, sand sucked his 4-year-old son up to his waist. Fortunately, the rescue team arrived on time and no tragedy occurred. Arnside is located near Morecambe Bay which is famous for its high tides. At low tide, the water recedes 11 km, exposing the sandy bottom of the bay. Daredevils who dare to step on this sand, which seems like solid ground, are instantly sucked in. The legs are squeezed by a hardened mass, and it is impossible to pull them out without any help. If this is not done in a timely manner, a person will die under the water of the tide (the water rises 9 meters!), as happened with Adrianna Dixon. Over the course of several years, more than 150 people died there.

Beware of quicksand

The ship, located in Atlantic Ocean 180 km from the coast of Canada, near which there are many reefs, which is why ships often crashed there and were thrown ashore. After several months, the sand sucked up the wreckage without leaving a trace. There are a lot of dangerous quicksand in Alaska, the longest of the peninsula's fjords, completely filled with quicksand, 150 km long.

And in the Sahara, one of the driest and most lifeless deserts on Earth, there is quicksand. Entire caravans disappear there without a trace. Nomads from the Tuareg tribe talk about heartbreaking screams that come from underground at night. They believe that these are the groaning souls of people who were swallowed up by the merciless belly of the desert. Relatively not so long ago, Russian scientists made a discovery based on photographs earth's surface, which were received from the satellite, a powerful underground river flows under the desert. It is likely that the waters of this river give some places in the desert the properties of fluidity.

Port Royal tragedy

It is difficult to even roughly estimate the number of victims of the deadly sands; in any case, it exceeds thousands, and possibly tens of thousands. 1692 - in Jamaica, quicksand swallowed up an entire area of ​​the city, then more than 2,000 people died. Port Royal was a very large, rich port, where the largest slave market was located. Since 1674, by appointment of the English monarch Charles II, the legendary pirate was appointed mayor of the city. But the place for the construction of the city was chosen extremely poorly. Port Royal was located on a 16-kilometer sand spit. Its top layer is still saturated with water today, and below there is a mixture of gravel, sand and rock fragments.

1692, June 7 - an earthquake began, and the sand under the city suddenly began to suck in buildings and people. Descriptions of the tragedy have been preserved in the historical chronicle. Some of the city's residents instantly sank into the ground, others were sucked in up to their knees or waist.

After the earthquake ended (it lasted six minutes), the sand instantly turned into a solid mass that resembled cement, which held the people tightly in its vice. People were suffocating, walled up alive in the ground. Most died, unable to get out; their bodies sticking out of the sand were eaten by wild dogs. Back in the 19th century, on the site of the buried city, the remains of the walls of collapsed houses stuck out of the sand. And in 1907, another earthquake occurred, which absorbed these silent evidence of the tragedy.

Goodwin Shoals

The South Foreland headland in England, where the Goodwin Shoals are located, has the grim reputation of being a "ship graveyard." There, on a vast sandbank, there are half-buried ships. Only what remains of the masts and rusty pipes of former conquerors of the seas stick out from the sand. The sands tenaciously hold onto their victims, and it is almost impossible to save the ships.

1946 - the ship Gelena Modjeska, whose cargo was estimated at three million dollars, fell victim to the Goodwin Sands. On September 12, the ship ran aground off the southern tip of South Foreland. For four days, 8 rescue tugs tried to save the ship, but on the 5th day, the Helena Modjeska broke in half, and the cargo and the ship fell victim to the sands.

1954 - in this place the sands 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.

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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 sources appear or when approaching groundwater to 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 path. 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 as an example hourglass), sand allows air to pass through. But if there is moisture between the grains of sand, air does not pass through, 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 rarefied space leads to reverse action– pulling the leg even deeper (“collapsing”).

Quicksand against man

At its core, quicksand can be classified as a type of non-Newtonian fluid with a high content of fines. solids(grains of sand). 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 it horizontal position 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 along 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

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 created with enormous force pulling leg back. 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 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.