The temperature of the mantle is thousands of degrees: closer to the core the temperature is higher, closer to the shell it is lower. Due to the difference in temperature, the substance of the mantle is mixed: hot masses rise up, and cold masses fall (just like boiling water in a pan or kettle, but this only happens thousands of times slower). Although the mantle is heated to enormous temperatures, due to the colossal pressure in the center of the Earth, it is not liquid, but viscous - like very thick tar. The lithosphere seems to float in a viscous mantle, submerged slightly into it under the weight of its weight.

Reaching the base of the lithosphere, the cooling mass of the mantle moves horizontally for some time along the solid lithosphere, but then, having cooled, it descends again towards the center of the Earth. While the mantle moves along the lithosphere, pieces of the lithospheric plate inevitably move along with it, while individual parts of the stone mosaic collide and creep onto each other.

The part of the plate that was below (on which another plate crawled) gradually sinks into the mantle and begins to melt. This is how magma is formed - a thick mass of molten rocks with gases and water vapor. Magma is lighter than the surrounding rocks, so it slowly rises to the surface and accumulates in so-called magma chambers, which are most often located along the line of plate collision. The magma is more fluid than the mantle, but still quite thick; Translated from Greek, “magma” means “thick paste” or “dough.”

The behavior of hot magma in a magma chamber really resembles yeast dough: the magma increases in volume, occupies all available space and rises from the depths of the Earth along cracks, trying to break free. Just as dough lifts the lid of a pan and flows over the edge, so magma breaks through the earth's crust in the weakest places and breaks out to the surface. This is a volcanic eruption.

A volcanic eruption occurs due to the degassing of magma. Everyone knows the degassing process: if you carefully open a bottle of a carbonated drink (lemonade, Coca-Cola, kvass or champagne), a pop is heard, and smoke appears from the bottle, and sometimes foam - this is gas coming out of the drink (that is, it is degassing) . If a bottle of champagne is shaken or heated before opening, a powerful stream will burst out of it, and it is impossible to stop this process. And if the bottle is not tightly closed, then this jet can itself knock the cork out of the bottle.

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A volcano erupts mainly due to magma, or more precisely, the process of its degassing. A similar process of loss of gases is often observed in everyday life (when you shake a bottle of mineral water or lemonade a little and then open it sharply, and with champagne it even opens on its own). So, magma, being under strong rock pressure, especially in those places where the earth’s crust is “loosely closed,” breaks out from under the Earth, knocking out the conditional “plug” of the volcano. The gases that are released begin to blaze and explode. Magma that loses its gases turns into lava. Gradually, the pressure at the site of magma formation decreases, which entails stopping the eruption. The volcano's mouth closes with cooled lava.

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While most of my friends and acquaintances are dreaming of moving from our Novosibirsk to Moscow, St. Petersburg and other “European” cities, I am flying to the country of volcanoes, to the Kamchatka Peninsula. I always dreamed of seeing an eruption with my own eyes and experiencing new sensations. To begin with, it would be nice to understand the very essence of this phenomenon.

The process of awakening a volcano

In simple and non-scientific terms, an eruption is the release of stones, ash and magma from the cone of a volcano to the surface. Often this is preceded by a wave of earthquakes. Residents of the Far East have become accustomed to such life. The reason for this is geological processes in the bowels of the Earth.

The spectacle is truly beautiful, but it is also the most dangerous and destructive natural disaster. For clarity, I recommend watching the feature film “Pompeii,” or once again experiencing the scale of the disaster depicted in the well-known painting.

Types of volcanoes by activity

Quite conventionally they distinguish:

• Active.
• Sleeping.
• Extinct.

In Russia, a striking example of an active volcano is Klyuchevskaya Sopka, which last raged some 5 years ago. By the way, the highest point in Europe - Mount Elbrus - is considered dormant. However, many scientists believe that he is about to wake up, probably in our century, then the scale of the disaster will be very terrible.

America's supervolcano as a threat to the entire planet

Separately, I would like to talk about the Yellowstone Caldera in the USA. Scientists from all over the world are seriously concerned about this “monster” that can change the Earth’s climatic conditions. Unlike ordinary volcanoes, this one is a huge depression. And if an explosion happens, then it can’t be called anything other than an apocalypse. No other catastrophe that has befallen the century of mankind can compare with this one. The only encouraging thing is that the last time this volcano went on rampage was several million years ago. I would like to believe, contrary to the opinions of all scientists, that our home will be safe for the same amount of time.

Let's live here and now, not think about the bad, about what is coming. I wish everyone to travel more, admire the mountains and peacefully sleeping volcanoes.

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I remember when I was a child I always hated chemistry. But who among us did not love laboratory work at one time? So, when we finally got tired of dipping litmus paper into a soda solution, the teacher finally came up with something more interesting and showed us a real (well, almost) volcanic eruption. That's when this process interested me.

The process of a volcanic eruption and its consequences

Inside our planet there is very strong pressure and high temperatures. Hot magma, finding the weakest points in the earth's crust, erupts outward and becomes lava, gradually hardening. This is how a volcano erupts.

Everything in the pictures is colorful, although the consequences can be very sad. Despite the fact that there are approximately 20 active volcanoes throughout the planet, they strike fear into humanity. Contrary to the common stereotype that the main danger is fire, this is far from the only disaster that every eruption leads to. Don’t forget about smoke and ash, poisonous gases, acid rain, climate change, etc. To be completely honest, volcanoes easily threaten the existence of humanity as such.

The most powerful eruptions

A volcanic eruption always leads to very sad consequences, but there are cases that are especially terrifying.

• Vesuvius. It seems to me that only small children have not heard about Vesuvius - the volcano that wiped Pompeii off the face of the Earth. During its weakest eruption they died - attention! - 4000 people. During the most powerful - 26,000.
• Unzen. Another “fire-breathing mountain” is located in Japan. Interestingly, the eruption itself did not lead to numerous casualties, but it did cause a tsunami that killed 15,000 people.
• Krakatoa. This volcano is located on an island in Indonesia. In 1883, there were 4 explosions with a power of 200 thousand times more than the explosion in Hiroshima. The inhabitants of this and neighboring islands died. The total number of victims is 40,000.

There is only one result from this. Volcanoes, despite their small number, easily endanger the lives of a huge number of people, and there are those that threaten the existence of all humanity.

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Mysterious phenomena occur on our amazing planet, which are sometimes very difficult to predict. I am, of course, lucky to live in Ukraine, where natural disasters practically never occur. But there are places that are increasingly being attacked by natural disasters, such as Japan, the USA and others. One such catastrophic event is a volcanic eruption.

Previously, I could not understand how a volcanic eruption occurs, but, watching the consequences and destruction on TV, I always empathized with the victims and wanted to help in some way. But, unfortunately, the only thing that can be done is to study, understand the power of nature, and warn about disasters so that losses and destruction are minimal.

How does a volcano erupt?

First of all, I tried to identify the main questions:

• how are they formed volcanoes;
• results volcanic activity;
• how regularly erupt.

To understand what a volcano is, you need to determine the reason for its formation.

How volcanoes form

The cause of volcanoes is hidden in the depths of the Earth. accumulated there heat meltsmatter of the earth's core. In those places where the pressure begins to weaken, the hot masses become liquid and form magma, that is, rock that melts and is saturated with gases. Magma makes its way to the earth's surface. The volcano is where magma and gases come to the surface. At the top of the volcano there is a crater similar in shape to a funnel.

Results of volcanic activity

Lava is the main a sign of an eruption. But there are others, such as scorching avalanche. This is a huge cloud of dust, black during the day and glowing red at night. An avalanche of hot blocks, sand and dust boiling underneath it moves at tremendous speed. Very dangerous results of volcanic activity are mud flows. Water from the crater mixes with soil, sand, stones and turns into mud. Streams of mud rush to the foot of the volcano with great speed, washing away everything in its path.

How regularly do they erupt?

Volcanoes can be active, dormant or extinct, depending on how they erupt. A volcano that constantly erupts is called current. Those volcanoes that are not active, but can awaken at any moment, are called sleeping. The same volcanoes that have not manifested themselves for thousands of years are extinct.

Unfortunately, we are not able to change natural disasters, but knowing their characteristics, we can protect and prevent terrible destruction and loss of life.

It is difficult to find a person who would not at least once be interested in volcanoes. Most have read books about them, watched with bated breath footage from eruption sites, at the same time admiring the power and magnificence of the elements and rejoicing that this is not happening near them. Volcanoes are something that leaves no one indifferent. So what is it?

Structure of the volcano

Volcanoes are special geological formations that arise when hot mantle material rises from the depths and reaches the surface. Magma rises up through cracks and faults in the earth's crust. Where it breaks out, active volcanoes are formed. This occurs at the boundaries of lithospheric plates, where faults arise due to their separation or collision. And the plates themselves are involved in movement when the mantle material moves.

Most often, volcanoes have the appearance of conical mountains or hills. Their structure clearly distinguishes a vent - a channel through which magma rises, and a crater - a depression at the top through which lava flows. The volcanic cone itself consists of many layers of activity products: solidified lava and ash.

Since the eruption is accompanied by the release of hot gases, glowing even during the day, and ash, volcanoes are often called “fire-breathing mountains.” In ancient times they were considered the gateway to the underworld. And they got their name in honor of the ancient Roman. It was believed that fire and smoke were flying from his underground forge. Such interesting facts about volcanoes fuel curiosity among a variety of people.

Types of volcanoes

The existing division into active and extinct is very arbitrary. Active volcanoes are those that have erupted within human memory. Eyewitness accounts of these events have been preserved. There are a lot of active volcanoes in the areas of modern mountain building. These are, for example, Kamchatka, the island of Iceland, East Africa, the Andes, and the Cordillera.

Inactive volcanoes are those that have not erupted for thousands of years. Information about their activity was not retained in people's memories. But there are many cases when a volcano, which was considered inactive for a long time, suddenly woke up and brought a lot of troubles. The most famous of them is the famous eruption of Vesuvius in 79, glorified by Bryullov’s painting “The Last Day of Pompeii.” 5 years before this disaster, the rebels were hiding on its top, and the mountain was covered with lush vegetation.

The extinct volcanoes include Mount Elbrus, the highest peak in Russia. Its double-headed apex consists of two cones merging at their bases.

Volcanic eruption as a geological process

An eruption is the process of releasing hot magmatic products in solid, liquid and gaseous states onto the earth's surface. It is individual for each volcano. Sometimes the eruption is quite calm, liquid lava pours out in streams and flows down the slopes. It does not interfere with the gradual release of gases, so strong explosions do not occur.

This type of eruption is typical for Kilauea. This volcano in Hawaii is considered one of the most active in the world. Its crater, with a diameter of about 4.5 km, is also the largest in the world.

If the lava is thick, it will occasionally clog the crater. As a result, the released gases, finding no way out, accumulate in the crater of the volcano. When the gas pressure becomes very high, a powerful explosion occurs. It lifts large volumes of lava into the air, which subsequently falls to the ground in the form of volcanic bombs, sand and ash.

The most famous explosive volcanoes are the already mentioned Vesuvius and Katmai in North America.

But the most powerful explosion, which led to cooling throughout the world due to volcanic clouds through which the sun's rays could hardly penetrate, occurred in 1883. Then I lost most of it. The column of gas and ash rose up to 70 km into the air. The contact of ocean water with hot magma led to the formation of a tsunami up to 30 m high. In total, about 37 thousand people became victims of the eruption.

Modern volcanoes

It is believed that there are now more than 500 active volcanoes in the world. Most of them belong to the Pacific “Ring of Fire” zone, located along the boundaries of the lithospheric plate of the same name. About 50 eruptions occur every year. At least half a billion people live in the area of ​​their activity.

Volcanoes of Kamchatka

One of the most famous areas of modern volcanism is in the Russian Far East. This is an area of ​​modern mountain building that belongs to the Pacific Ring of Fire. The volcanoes of Kamchatka are included in the UNESCO World Heritage List. They are of great interest not only as objects of scientific research, but also as natural monuments.

This is where the highest active volcano in Eurasia, Klyuchevskaya Sopka, is located. Its height is 4750 m. Plosky Tolbachik, Mutnovskaya Sopka, Gorely, Vilyuchinsky, Gorny Zub, Avachinskaya Sopka and others are also widely known for their activity. In total, there are 28 active volcanoes in Kamchatka and about half a thousand extinct ones. But here are some interesting facts. A lot is known about the volcanoes of Kamchatka. But along with this, the region is known for a much rarer phenomenon - geysers.

These are springs that periodically emit fountains of boiling water and steam. Their activity is associated with magma that rises through cracks in the earth's crust close to the earth's surface and heats the groundwater.

The famous Valley of Geysers, located here, was discovered in 1941 by T. I. Ustinova. It is rightfully considered one of the wonders of nature. The area of ​​the Valley of Geysers is no more than 7 square meters. km, but there are 20 large geysers and dozens of springs with boiling water. The largest - the Giant Geyser - throws out a column of water and steam to a height of about 30 m!

Which volcano is the tallest?

This is not so easy to determine. Firstly, the height of active volcanoes can increase with each eruption due to the growth of a new layer of rocks or decrease due to explosions that destroy the cone.

Secondly, a volcano that was considered extinct may awaken. If it is high enough, it can push back the existing leader.

Thirdly, where to calculate the height of the volcano - from the base or from sea level? This gives completely different numbers. After all, the cone that has the greatest absolute height may not be the largest compared to the surrounding area, and vice versa.

Currently, among the active volcanoes, Lluillayllaco in South America is considered the largest. Its height is 6723 m. But many volcanologists believe that Cotopaxi, located on the same continent, can claim the title of the greatest. It may have a lower height - “only” 5897 m, but its last eruption was in 1942, and that of Lluillailhaco - already in 1877.

Hawaiian Mauna Loa can also be considered the highest volcano on Earth. Although its absolute height is 4169 m, this is less than half of its true height. The cone of Mauna Loa starts from the very ocean floor and rises more than 9 km. That is, its height from the base to the top exceeds the size of Chomolungma!

Mud volcanoes

Has anyone heard of the Valley of Volcanoes in Crimea? After all, it is very difficult to imagine this peninsula shrouded in the smoke of eruptions, and the beaches filled with hot lava. But you don’t have to worry, because we are talking about mud volcanoes.

This is not such a rare phenomenon in nature. Mud volcanoes are similar to real ones, but they do not emit lava, but streams of liquid and semi-liquid mud. The cause of eruptions is the accumulation of large amounts of gases, most often hydrocarbons, in underground cavities and cracks. The gas pressure activates the volcano, a high column of mud sometimes rises several tens of meters, and the ignition of the gas and explosions give the eruption a rather menacing appearance.

The process can last several days, accompanied by a local earthquake and underground rumble. As a result, a low cone of frozen mud is formed.

Areas of mud volcanism

In Crimea, such volcanoes are found on the Kerch Peninsula. The most famous of them is Jau Tepe, which greatly frightened local residents with its short eruption (only 14 minutes) in 1914. A column of liquid mud was thrown 60 m up. The length of the mud flow reached 500 m with a width of more than 100 m. But such large eruptions are rather an exception.

The areas where mud volcanoes are active often coincide with oil and gas production sites. In Russia they are found on the Taman Peninsula, on Sakhalin. Among neighboring countries, Azerbaijan is “rich” in them.

In 2007, the volcano became active, flooding a vast area with its mud, including many buildings. According to the local population, this happened due to the drilling of a well, which disturbed the deep layers of rocks.

Edinburgh Castle in Scotland was built on top of an extinct volcano. And most Scots don't even know about it.

It turns out that volcanoes can be actors! In the film “The Last Samurai”, Taranaki, considered the most beautiful in New Zealand, played the role of the sacred Japanese mountain Fuji. The fact is that the surroundings of Fuji with its urban landscapes were in no way suitable for filming a film about the events of the late 19th century.

In general, New Zealand volcanoes do not have to complain about the lack of attention from film directors. After all, Ruapehu and Tongariro became famous largely thanks to the film “The Lord of the Rings,” in which they depicted Orodruin, in the flames of which the One Ring was created and subsequently destroyed there. The Lonely Mountain in Erebor in The Hobbit is also one of the local volcanoes.

And Kamchatka geysers and waterfalls became the backdrop for the filming of the film “Sannikov Land”.

The eruption of Mount St. Helens (USA) in 1980 is considered the most powerful eruption of the entire 20th century. The explosion, equal in power to 500 bombs dropped on Hiroshima, sent ash across four states.

Eyjafjallajökull became famous for throwing ash and smoke into chaos in European air traffic in the spring of 2010. And its name has baffled hundreds of radio and television announcers.

The Philippine volcano Pinatubo last erupted in 1991. At the same time, two American military bases were destroyed. And after 20 years, the Pinatubo crater was filled with rainwater, forming an amazingly beautiful lake, the slopes of the volcano were overgrown with tropical vegetation. This made it possible for travel agencies to organize holidays with swimming in the volcanic lake.

Eruptions often produce interesting rocks. For example, the lightest stone is pumice. Numerous air bubbles make it lighter than water. Or the "Pele's hair" found in Hawaii. They are long thin threads of the rock. Many buildings in the capital of Armenia, Yerevan, are built from pink volcanic tuff, which gives the city a unique flavor.

Volcanoes are a formidable and majestic phenomenon. Interest in them is caused by fear, curiosity, and thirst for new knowledge. It’s not for nothing that they are called windows to the underworld. But there are purely utilitarian interests. For example, volcanic soils are very fertile, which has forced people to settle near them for centuries, despite the danger.

Volcanic eruption diagram

When a volcano awakens and begins spewing streams of red-hot lava, one of the most amazing natural phenomena occurs. This happens when there is a hole, crack or weak spot in the earth's crust. Molten rock, called magma, rises from the depths of the Earth, where there are incredibly high temperatures and pressures, to its surface. The magma that flows out is called lava. Lava cools, hardens, and forms volcanic, or igneous, rock. Sometimes lava is liquid and flowing. It oozes from the volcano like boiling syrup and spreads over a large area. When such lava cools, it forms a hard cover of rock called basalt. With the next eruption, the thickness of the cover increases, and each new layer of lava can reach 10 m. Such volcanoes are called linear or fissure, and their eruptions are calm.

During explosive eruptions, the lava is thick and viscous. It pours out slowly and hardens near the crater of the volcano. With periodic eruptions of this type of volcano, a high conical mountain with steep slopes appears, the so-called stratovolcano.

The lava temperature can exceed 1000 °C. Some volcanoes emit clouds of ash that rise high into the air. Ash can settle near the volcano's mouth, and then an ash cone appears. The explosive force of some volcanoes is so great that huge blocks of lava the size of a house are thrown out. These "volcano bombs" fall near a volcano.

Along the entire mid-ocean ridge, lava seeps up from the mantle from many active volcanoes onto the ocean floor. From deep-sea hydrothermal vents located near volcanoes, gas bubbles and hot water with minerals dissolved in them erupt

An active volcano regularly spews lava, ash, smoke and other products. If there is no eruption for many years or even centuries, but in principle it can happen, such a volcano is called dormant. If a volcano has not erupted for tens of thousands of years, it is considered extinct. Some volcanoes emit gases and streams of lava. Other eruptions are more violent and produce huge clouds of ash. More often than not, lava oozes slowly onto the Earth's surface over a long period of time without any explosions occurring. It pours out from long cracks in the earth's crust and spreads, forming lava fields.

Where do volcanic eruptions occur?

Most volcanoes are located on the edges of giant lithospheric plates. There are especially many volcanoes in the subduction zone, where one plate dives under another. When the lower plate melts in the mantle, the gases and fusible rocks it contains “boil” and, under enormous pressure, burst upward through cracks, causing eruptions.

Cone-shaped volcanoes, typical of land, look huge and powerful. However, they account for less than one hundredth of all volcanic activity on Earth. Most of the magma flows to the surface deep underwater through cracks in the mid-ocean ridges. If underwater volcanoes erupt large enough amounts of lava, their peaks reach the surface of the water and become islands. Examples are the Hawaiian Islands in the Pacific Ocean or the Canary Islands in the Atlantic.

Rainwater can seep through cracks in the rock into deeper layers, where it is heated by magma. This water comes to the surface again in the form of a fountain of steam, splashes and hot water. Such a fountain is called a geyser.

Santorini was an island with a dormant volcano. Suddenly, a monstrous explosion demolished the top of the volcano. Explosions followed day after day as sea water entered the crater containing molten magma. The island was practically destroyed by the last explosion. All that remains of it today is a ring of small islands.

Largest volcanic eruptions

• 1450 BC e., Santorini, Greece. The largest explosive eruption of ancient times.
• 79, Vesuvius, Italy. Described by Pliny the Younger. Pliny the Elder died in the eruption.
• 1815, Tambora, Indonesia. More than 90,000 human casualties.
• 1883, Krakatoa, Java. The roar could be heard 5000 km away.
• 1980, St. Helens, USA. The eruption was captured on film.

Natural disasters can be different, but one of the most dangerous is rightfully recognized. Every day, up to ten such emissions occur on the planet, many of which people do not even notice.

What is a volcano?

A volcano is a geological formation located on the crust. Where craters are located, magma comes out and forms lava, followed by gases and rock fragments.

The stone giant received its name from the ancient Roman god of fire, who bore the majestic name Vulcan.

Classification

Such mountains can be classified according to several criteria. So, for example, according to their form, these formations are divided into the following types:

1. Shield ones.
2. Stratovolcanoes.
3. Slag.
4. Cone-shaped.
5. Dome.

In addition, volcanoes can be identified depending on their location:

1. Ground.
2. Underwater.
3. Subglacial.

In addition, among ordinary people there is another, simple classification, which depends on the degree of volcanic activity:

1. Active. This formation is characterized by the fact that it erupted relatively recently.
2. This definition refers to a mountain that is currently inactive but may erupt in the future.
3. An extinct volcano is a tectonic formation that no longer has the ability to gush.

Why do volcanoes erupt?

Before you understand the products that come out of a volcano during an eruption, you need to know what this terrible phenomenon is and what its causes are.

An eruption means the release of lava flows to the surface, which is accompanied by the release of gases and ash. Volcanoes erupt due to a large amount of substances accumulated in the magma.

What comes out of a volcano during an eruption?

Magma is constantly under very high pressure, so gases always remain dissolved in it as a liquid. The molten rock, which is gradually pushed towards the surface by the onslaught of volatile substances, passes through cracks and enters the hard layers of the mantle. Here the magma quickly comes out.

It would seem that there should be no more questions about what appears during a volcanic eruption, because magma turns into lava and spills onto the surface. However, in fact, during an eruption, in addition to the indicated components, many different substances can reveal themselves to the world.

Lava

Lava is the most famous product released during active volcanic activity. This is what people most often point to when answering the question: “What comes out of a volcano during an eruption?” A photo of this hot substance can be seen in the article.

Lava masses are compounds of silicon, aluminum and other metals. There is also an interesting fact associated with it: it is known that it is the only earthly product in which all the elements found in the periodic table can be found.

Lava is hot magma that flows from the crater of a volcano and flows down its slopes. During ascent, the composition of the underground guest constantly undergoes changes due to atmospheric factors. In addition, a large amount of gases that rise to the surface along with the magma make it bubbly.

The average is 1000 degrees, so it easily destroys all obstacles that come in its way.

Wreckage

It is no less interesting to consider what comes out during a volcanic eruption, besides lava. At the height of the process, huge fragments, which scientists call “tephra,” are thrown onto the surface of the earth.

Of the total mass, the largest fragments are distinguished, nicknamed “volcanic bombs”. These fragments are liquid products that freeze in the air during release. The size of such stones can vary: the smallest of them are similar to peas, and the largest exceed the size of a walnut.

Ash

Also, when answering the question “What comes out of a volcano?”, we must not forget about ash. It is this that often leads to catastrophic consequences, since it is released even during a minor eruption that cannot harm people.

Small ash particles spread through the air at enormous speeds - up to 100 kilometers per hour. Naturally, a significant amount of this substance can enter a person’s throat during breathing, so during an eruption you should cover your face with a scarf or a special respirator. The peculiarity of ash is that it is able to cross vast distances, even bypassing water and hills. These small particles are so hot that they constantly glow in the dark.

Gases

We should not forget that, among other things, a large amount of gases comes out of a volcano during an eruption. This volatile mixture consists of hydrogen, sulfur and carbon. Contains boron, bromic acid, mercury, and metals in small quantities.

All gases that are released during an eruption are white. And if tephra is mixed with the gases, the clouds take on a black tint. Often, it is by the black smoke coming from a volcanic crater that people determine that an eruption will occur soon and they need to evacuate.

In addition, you need to know what comes out of a volcano during an eruption, in addition to the substances listed above. This is a strong smell of hydrogen sulfide. So, for example, on some islands the volcanic spirit spreads over hundreds of kilometers.

A remarkable fact: a small amount of gas continues to be released from the volcano for several years after the eruption. Moreover, such emissions are very toxic, and when they get into the water with rain, they poison it and make it unfit for drinking.

There are volcanoes on every continent except Australia, even Antarctica. The main locations of the volcano are mainly in seismically active zones, faults in the earth's crust and at the junctions of tectonic plates. Active volcanoes are found in parts of the world that are also most prone to earthquakes, where there is most movement underground.

There are not only active volcanoes, but also so-called “dormant volcanoes”. Moreover, the latter pose no less danger, since they can wake up at any time. The most active volcanoes erupt once every few years, and all active volcanoes erupt once every 10-15 years.

Usually, before the main eruption, volcanoes become active, which is expressed in rumbling, emissions of steam and gases. The smell of sulfur from local rivers, stinging acid rain, loud rumbles, or clouds of steam coming from a volcano are all warning signs.

Harbingers of volcanic eruptions.

- Increased release of gases.
— Increase in soil temperature on the slopes of the volcano.
— Intensification of its seismic activity, expressed in a series of tremors of varying strength.
— Swelling of the volcanic cone and a change in the slope of its surface.

During an eruption, hot and molten magma pours out of the volcano in the form of lava flows. Entering this zone is deadly and can, at best, lead to severe burns. When pressure forces molten rock (magma) through a crack towards the surface, a channel is formed - merlot. This channel usually becomes the main outlet for subsequent eruptions, although other channels may appear. A strong eruption can tear off an entire mountain top.

The molten rock, commonly called lava when this mass reaches the surface, can be of two types: granite lava, which is thick and slow moving, and basaltic lava, which flows faster and has a speed of 8-16 km/h. Granite lava tends to clog the vent of a volcano, which is eventually cleared by an explosion due to the build-up of pressure below. Lava and pieces of rock are scattered over long distances and cause fires.

Lava flows, under the influence of air from above, become covered with a dark and rather dense crust, on which you can sometimes even walk, but this is extremely dangerous due to the threat of not only burning through, but also falling into a hot flow, the temperature of which is several hundred degrees. Being near a crater or on the slope of a volcano is dangerous not only during an eruption, but also because various poisonous gases often escape from the ground. Such gas outlets are called fumaroles. Often carbon dioxide, which has neither color nor odor, accumulates in depressions of the relief and can cause severe, often fatal poisoning. Jets of hot steam often escape from cracks in the ground.

The dangers of a volcanic eruption and human behavior in the danger zone.

Lava.

Although in most cases it is possible to run away or even walk away from basaltic lava flows, they flow non-stop until they reach the valley floor or eventually cool. They destroy or cover everything in their path. Lava flows are probably the least dangerous to life in an eruption, as a normal healthy person can walk away from it.

Volcanic "bombs".

Volcanic “bombs”, ranging in size from small pebbles to huge pieces of stone and plastic hot lava, can fly over considerable distances. Volcanic ash “rain” can cover much larger areas, with certain amounts of volcanic dust rising to great heights and spreading around the world, influencing the weather. When evacuating from the area adjacent to the volcano, hard helmets like those worn by construction workers, motorcyclists or jockeys can provide some protection. At greater distances, where evacuation may not be necessary, protection from the effects of ash and accompanying rain should be provided.

Volcanic ash.

But perhaps an even more terrible phenomenon is the fall of hot ash, which not only destroys everything around, but can also cover entire cities in a thick layer. If you get caught in such an ashfall, it is almost impossible to escape. Volcanic ash is not actually ash, but a powdery rock ejected from a volcano in a cloud of steam and gases. It is abrasive, irritating and heavy - its weight can cause roofs to break. It can suffocate crops, block roads and waterways, and when combined with toxic gases, it can also cause lung complications in children, the elderly and those with lung disease.

In order to poison a healthy person, a sufficient concentration of poisonous gases occurs only very close to the eruption. But when sulfur dioxide contained in an ash cloud combines with rain, it produces sulfuric acid (and sometimes others) in concentrations that can cause burns to the skin, eyes and mucous membranes. Wear goggles (ski goggles or a diving mask will seal your eyes, but not sun protection). Use a damp cloth to cover your mouth and nose, or industrial face masks if available. Once you reach shelter, remove clothing, thoroughly wash exposed areas of your body, and rinse your eyes with clean water.

The “Scorching Cloud” phenomenon.

A cloud of gas and dust can roll down the slope of the volcano at a speed of more than 160 km/h. It is red hot and moves so fast that it is impossible to escape from it. This phenomenon is often called a "scorching cloud." Unless there is a solid underground shelter nearby, your only chance of survival is to dive underwater and hold your breath for about half a minute until the hot cloud passes.

Mud flows.

Powerful mud flows like mudflows also occur during volcanic eruptions. A volcano can melt snow and cause a water-ice or mud flow mixed with earth. It can travel at speeds of up to 100 km/h with devastating effects, as seen in Colombia in 1985. In a narrow valley its height can reach 30 meters.

Flows remain dangerous long after the main eruption and are a potential threat even when the volcano is dormant, as long as it produces enough heat to melt water that will be trapped by ice barriers. Heavy rains can cause these ice dams to collapse. When evacuating by car, remember: ash can make roads slippery, even if it doesn't block them. Avoid routes through valleys, which can become mud flow routes.

Based on materials from the book “Encyclopedia of Survival.”
Chernysh I. V.