What does a volcano look like? Volcanoes: characteristics and types. Geographic feature. Significance of volcanoes

Volcanic eruption is an interesting but dangerous phenomenon. Rarely does anyone dare to come close to them. And then most of the photos are from the air, which is no less dangerous. Have you seen what eruptions look like from space?

1. Stratovolcano Sarychev

The eruption of the 1,446-meter stratovolcano Sarychev in the Kuril Islands, taken by NASA astronauts from the International Space Station. The shock wave dispersed the clouds, so the astronauts managed to shoot such a detailed and detailed frame.

2. Wolf

The eruption of Wolf - the highest volcano in the Galapagos Islands. The height of the volcano is 1,710 meters, and a lake with several fragile islands formed directly in its crater. The last eruption began on May 25, 2015.

3. Volcano Klyuchevskaya Sopka

Volcano Klyuchevskaya Sopka, also known as Klyuchevskoy volcano, is an active stratovolcano in the east of Kamchatka. It is the highest (4,835 m) active volcano on the Eurasian continent, which is over 7,000 years old.

4. Etna

Etna is the largest European stratovolcano, located on the east coast of Sicily, near the cities of Messina and Catania. Now the height of Etna is 3.329 m above sea level, and it often changes from eruption to eruption.

5. Volcano Merapi

A picture taken from the DigitalGlobe satellite shows a powerful eruption of Mount Merapi in Indonesia. Recently, a volcanic eruption on the outskirts of the city of Yogyakarta in the central part of the island of Java has killed 194 people, 320 thousand residents have lost their homes.

In ancient Rome, the name Vulcan was given to a mighty god, patron of fire and blacksmithing. We call volcanoes geological formations on the surface of the land or on the ocean floor, through which lava comes out of the deep interior of the earth to the surface.

Often accompanied by earthquakes and tsunamis, major volcanic eruptions have had a significant impact on human history.

Geographic feature. Significance of volcanoes

During a volcanic eruption, magma comes to the surface through cracks in the earth's crust, forming lava, volcanic gases, ash, volcanic rocks, and pyroclastic flows. Despite the danger posed to humans by these mighty natural objects, it was thanks to the study of magma, lava and other products of volcanic activity that we managed to gain knowledge about the structure, composition and properties of the lithosphere.

It is believed that thanks to volcanic eruptions, protein forms of life could appear on our planet: eruptions released carbon dioxide and other gases necessary for the formation of the atmosphere. And volcanic ash, settling, became an excellent fertilizer for plants due to the potassium, magnesium and phosphorus contained in it.

The role of volcanoes in regulating the climate on Earth is invaluably important: during the eruption, our planet “lets off steam” and cools, which largely saves us from the effects of global warming.

Characteristics of volcanoes

Volcanoes differ from other mountains not only in composition, but also in strict external outlines. From the craters at the top of the volcanoes, deep narrow ravines formed by streams of water stretch down. There are also entire volcanic mountains formed by several nearby volcanoes and their eruptions.

However, a volcano is not always a mountain breathing fire and heat. Even active volcanoes can look like straight cracks on the surface of the planet. There are especially many such "flat" volcanoes in Iceland (the most famous of them, Eldgja, has a length of 30 km).

Types of volcanoes

Depending on the degree of volcanic activity, there are: current, conditionally active and dormant ("sleeping") volcanoes. The division of volcanoes according to activity is very conditional. There are cases when volcanoes, considered extinct, began to show seismic activity and even erupt.

Depending on the shape of volcanoes, there are:

• Stratovolcanoes- classic "fire mountains" or volcanoes of the central type of a cone-shaped shape with a crater at the top.
• Volcanic crevices or fissures- Faults in the earth's crust through which lava comes to the surface.
• calderas- depressions, volcanic cauldrons formed as a result of the failure of a volcanic peak.
• Shield- are called so because of the high fluidity of the lava, which, flowing for many kilometers in wide streams, forms a kind of shield.
• lava domes - formed by the accumulation of viscous lava above the vent.
• Cinder or tephra cones- have the shape of a truncated cone, consist of loose materials (ash, volcanic stones, boulders, etc.).
• complex volcanoes.

In addition to terrestrial lava volcanoes, there are underwater and mud(spewing liquid mud, not magma) Underwater volcanoes are more active than terrestrial ones, through them 75% of the lava erupted from the bowels of the Earth is ejected.

Types of volcanic eruptions

Depending on the viscosity of the lavas, the composition and amount of eruption products, 4 main types of volcanic eruptions are distinguished.

Effusive or Hawaiian type- relatively quiet eruption of lava formed in craters. The gases released during the eruption form lava fountains from drops, filaments and lumps of liquid lava.

Extrusion or dome type- accompanied by the release of gases in large quantities, leading to explosions and emissions of black clouds from ash and lava debris.

Mixed or strombolian type- abundant lava output, accompanied by small explosions with ejection of pieces of slag and volcanic bombs.

hydroexplosive type- characteristic of underwater volcanoes in shallow water, accompanied by a large amount of steam released when magma contacts water.

The largest volcanoes in the world

The highest volcano in the world is Ojos del Salado located on the border between Chile and Argentina. Its height is 6891 m, the volcano is considered extinct. Among the active "fire mountains" the highest is Llullaillaco- volcano of the Chilean-Argentine Andes with a height of 6,723 m.

The largest (among terrestrial) in terms of area is a volcano mauna loa on the island of Hawaii (height - 4,169 m, volume - 75,000 km 3). mauna loa also one of the most powerful and active volcanoes in the world: since its “awakening” in 1843, the volcano has erupted 33 times. The largest volcano on the planet is a huge volcanic massif Tamu(area 260,000 km 2), located at the bottom of the Pacific Ocean.

But the strongest eruption for the entire historical period was produced by a “low” Krakatoa(813 m) in 1883 in the Malay Archipelago in Indonesia. Vesuvius(1281) - one of the most dangerous volcanoes in the world, the only active volcano in continental Europe - is located in southern Italy near Naples. Exactly Vesuvius destroyed Pompeii in 79.

In Africa, the highest volcano is Kilimanjaro (5895), and in Russia - a two-peak stratovolcano Elbrus(Northern Caucasus) (5642 m - western peak, 5621 m - eastern).

We want to show you a series of photographs taken from space, which reflect this phenomenal natural phenomenon.

He was photographed on June 12, 2009 aboard the International Space Station. The Sarychev volcano is one of the busiest in the Kuril archipelago.

The eruption was captured by astronauts aboard the space shuttle Endeavor in 1994.

Astronauts from the International Space Station took this picture on May 18, 2013.

Manam Volcano is located 13 kilometers off the coast of Papua New Guinea and forms an island 10 kilometers wide. This is a stratovolcano consisting of two craters, both active, but large eruptions are characteristic only for the southern crater. The photo was taken on June 16, 2010.

After awakening on June 4, 2011, the volcano continued to spew smoke for at least two days. It is located in Chile, right on the border with Argentina.

NASA's Terra satellite flew over a volcano in Iceland on May 6, 2014.

The Nyiragongo lava lake has been drained and refilled several times during eruptions that have occurred in recent decades. In 2002, lava reached the city of Goma, killing dozens of people.

The volcano erupted on January 26, 2011. Scattered ash swirled over the city of Miyazaki, causing plane flights to be canceled, trains to stop, and schools to close in the area. The image was taken by the Terra satellite on February 4, 2011.

Merapi is one of the most active volcanoes in Indonesia, its height almost reaches 3000 meters. About 50 thousand people permanently live in the region, they cultivate fertile soil fertilized with lava, but are exposed to the danger that the eruption brings with it. The photo was taken on August 24, 2003.

At the end of May 2013, the Api volcano woke up on a small island in Indonesia, which caused the cancellation of many flights. The column of smoke rose up to 20 km in height.

Etna is the highest active volcano in Europe.

After more than 9,000 years of silence, this Chilean volcano woke up again on May 2, 2008. 4,000 residents of the city of Chaiten, located 10 kilometers from the epicenter, were forced to evacuate by ship.

On August 24, 79, people looked in horror at their patron and could not understand: why did they anger the gods so much. How did it happen that their protector suddenly began to spew fire that spread across the ground and destroyed everything in its path? The inhabitants of Pompeii already knew: unexpectedly for everyone, a volcano woke up. What is it, what are volcanoes and why do they suddenly wake up, we will consider today in this article.

What is a volcano?

A volcano is a kind of formation on the surface of the earth's crust, which from time to time is capable of spewing pyroclastic flows (a mixture of ash, gas and stones), volcanic gases, and also lava. It is in zones of volcanic activity that opportunities for the use of geothermal energy open up.

Types of volcanoes

Scientists have adopted a classification of volcanoes into active, dormant and extinct.

1. Volcanoes that erupt during a historical period of time are called active volcanoes. It is thanks to them that one can understand what a volcano is and the mechanisms that make it work, because direct observation of the process provides much more information than the most thorough excavations.
2. Sleeping volcanoes are called, which are currently not active, however, there is a high probability of their awakening.
3. Extinct volcanoes include those that were active in the past, but today the probability of their eruption is equal to zero.

What shape are volcanoes?

If you ask a schoolboy what shape a volcano has, he will undoubtedly say that it looks like a mountain. And he will be right. The volcano really has the shape of a cone, which formed during its eruption.

The volcanic cone has a vent - this is a kind of outlet channel through which lava rises during an eruption. Quite often there is more than one such channel. It may have several branches that serve to bring volcanic gases to the surface. The crater always ends in a crater. It is into it that all materials are thrown during the eruption. An interesting fact is that the mouth is open only during the active period of the volcano. The rest of the time it is closed, until the next manifestation of activity.

The time during which a volcanic cone formed is individual. Basically, it depends on how much material the volcano throws out during its eruption. Some take 10,000 years to do so, while others can form it in a single eruption.

Sometimes the opposite happens as well. During an eruption, the volcanic cone collapses, and a large depression, the caldera, forms in its place. The depth of such a depression is at least one kilometer, and the diameter can reach 16 km.

Why do volcanoes erupt?

What is a volcano, we figured it out, but why does it erupt?

As you know, our planet does not consist of a single piece of stone. It has its own structure. Above - a thin solid "shell", which scientists call the lithosphere. Its thickness is only 1% of the radius of the globe. In practice, this means between 80 and 20 kilometers, depending on whether it is land or the bottom of the oceans.

Beneath the lithosphere is the mantle layer. Its temperature is so high that the mantle is constantly in a liquid, or rather viscous, state. In the center is the solid core of the earth.

As a result of the fact that the lithospheric plates are in constant motion, magma chambers can arise. When they break out to the surface of the earth's crust, a volcanic eruption begins.

What is magma?

Here, perhaps, it is necessary to explain what magma is and what chambers it can form.

Being in constant motion (albeit invisible to the naked eye of a person), lithospheric plates can collide or crawl into each other. Most often, the plates, the dimensions of which are larger, "win" those whose thickness is less. Therefore, the latter are forced to sink into the boiling mantle, the temperature of which can reach several thousand degrees. Naturally, at this temperature, the plate begins to melt. This molten rock with gases and water vapor is called magma. In its structure, it is more liquid than the mantle, and also lighter.

How does a volcano erupt?

Due to the named features of the magma structure, it begins to slowly rise and accumulate in places called foci. Most often, such foci are places of a break in the earth's crust.

Gradually, magma occupies all the free space of the hearth and, in the absence of another way out, begins to rise along cracks in the earth's crust. If magma finds a weak point, it does not miss the opportunity to break out to the surface. At the same time, thin sections of the earth's crust break through. This is how a volcano erupts.

Locations of volcanic activity

So what places on the planet, given volcanic activity, can be considered the most dangerous? Where are the most dangerous volcanoes in the world located? Let's figure it out...

1. Merapi (Indonesia). It is the largest volcano in Indonesia and also the most active. He does not let the locals forget about him even for one day, constantly releasing smoke from his crater. At the same time, small eruptions occur every two years. But large ones do not have to wait long: they happen every 7-8 years.
2. If you want to know where the volcanoes are, you should probably take a trip to Japan. This is truly a "paradise" of volcanic activity. Take, for example, Sakurajima. Since 1955, this volcano has been a constant concern for the locals. Its activity does not even think of decreasing, and the last major eruption occurred not so long ago - in 2009. A hundred years ago, the volcano had its own island, but thanks to the lava that he spewed out of himself, he managed to connect with the Osumi Peninsula.
3. Aso. And Japan again. This country is constantly suffering from volcanic activity, and the Aso volcano is proof of this. In 2011, an ash cloud appeared over it, the area of ​​\u200b\u200bwhich was more than 100 kilometers. Since that time, scientists have been constantly recording tremors, which can only indicate one thing: the Aso volcano is ready for a new eruption.
4. Etna. This is the largest volcano in Italy, which is interesting in that it has not only the main crater, but also many small ones located along its slope. In addition, Etna is distinguished by enviable activity - small eruptions occur every two to three months. It must be said that the Sicilians have long been accustomed to such a neighborhood, and are not afraid to populate the slopes.
5. Vesuvius. The legendary volcano is almost half the size of its Italian brother, but this does not prevent him from setting many of his own records. Vesuvius, for example, is the volcano that destroyed Pompeii. However, this is not the only city that has suffered from his activity. According to scientists, Vesuvius destroyed cities that were not lucky enough to be close to its slopes more than 80 times. The last major eruption happened in 1944.

Which volcano on the planet can be called the highest?

There are quite a few record holders among these volcanoes. But what can bear the title "The highest volcano on the planet"?

Keep in mind: when we say "highest", we do not mean the height of the volcano above the surrounding area. This is the absolute height above sea level.

So, scientists call the Chilean Ojos del Salado the highest active volcano in the world. For a long time he was referred to as sleeping. This status of the Chilean allowed the Argentinean Lullaillaco to bear the title of "The Highest Volcano in the World". However, in 1993, Ojos del Salado produced an ash ejection. After that, he was carefully examined by scientists who managed to find fumaroles (outlets of steam and gas) in his mouth. Thus, the Chilean changed his status, and, without knowing it, brought relief to many schoolchildren and teachers, for whom it is not always easy to pronounce the name Llullaillaco.

For the sake of justice, it must be said that Ojos del Salado does not have a high volcanic cone. It rises above the surface only 2000 meters. While the relative height of the Lullaillaco volcano is almost 2.5 kilometers. However, it is not for us to argue with scientists.

The Truth About Yellowstone Volcano

You cannot boast that you know what a volcano is if you have never heard of Yellowstone, which is located in the USA. What do we know about him?

First of all, Yellowstone is not a high volcano, but for some reason it is called a supervolcano. What is the matter here? And why was it possible to discover Yellowstone only in the 60s of the last century, and even then with the help of satellites?

The fact is that the cone of Yellowstone collapsed after its eruption, resulting in the formation of a caldera. Given its gigantic size (150 km), it is no wonder that people could not see it from Earth. But the collapse of the crater does not mean that the volcano can be reclassified as dormant.

There is still a huge magma chamber under the Yellowstone crater. According to the calculations of scientists, its temperature exceeds 800 ° C. Thanks to this, many thermal springs have formed in Yellowstone, and, in addition, jets of steam, hydrogen sulfide and carbon dioxide constantly come out to the surface of the earth.

Not much is known about the eruptions of this volcano. Scientists believe that there were only three of them: 2.1 million, 1.27 million and 640 thousand years ago. Given the frequency of eruptions, we can conclude that we may witness the following. I must say that if this really happens, the Earth will face the next Ice Age.

What troubles do volcanoes bring?

Even if you do not take into account the fact that Yellowstone can suddenly wake up, the eruptions that other volcanoes in the world can prepare for us cannot be called harmless either. They lead to huge destruction, especially if the eruption happened suddenly and there was no time to warn or evacuate the population.

The danger is not only lava, which can destroy everything in its path and cause fires. Do not forget about the poisonous gases that spread over vast areas. In addition, the eruption is accompanied by ash emissions, which can cover vast areas.

What to do if the volcano "comes to life"?

So, if you were at the wrong time and in the wrong place when the volcano suddenly woke up, what to do in such a situation?

First of all, you need to know that the speed of the lava is not that great, only 40 km / h, so it is quite possible to run away, or rather, leave it. This must be done in the shortest way, that is, perpendicular to its movement. If this is not possible for some reason, you need to seek shelter on a hill. It is necessary to take into account the likelihood of a fire, therefore, if possible, it is necessary to clean the shelter from ash and incandescent debris.

In open areas, a body of water can save you, although much depends on its depth and the force with which the volcano erupts. The photos that were taken after the eruption show that a person is often defenseless in front of such a powerful force.

If you were among the lucky ones, and your house survived the eruption, be prepared to spend at least a week there.

And most importantly, do not trust those who say that "this volcano has been sleeping for thousands of years." As practice shows, any volcano can wake up (photos of the destruction confirm this), but there is not always someone to tell about it.

Volcanoes are geological formations on the surface of the Earth (or another planet), where red-hot magma comes to the surface, forming lava, volcanic gases and pyroclastic flows.
The word "volcano" comes from the name of the ancient Roman god of fire, Vulcan. There are about 1,500 active volcanoes in the world, most of which are located along the Pacific Ring of Fire, and about 50 of them erupt every year. Nearly 500 million people live near active volcanoes.
What a volcanic eruption looks like from space.

Chaiten is an active volcano in Chile.

Height above sea level - 1122 m. The caldera of the volcano is about 3 km in diameter, at the bottom of it there are several crater lakes. The volcano was not active for 9400-9500 years, until a major eruption began on May 2, 2008, the ejection reached 30 km in height. On May 6, the lava reached the village, and almost the entire population was evacuated within a radius of 50 km. (Photo by NASA):

2

Sarychev Volcano, Russia

Sarychev Volcano - an active stratovolcano on the island of Matua of the Great Kuril Ridge; one of the most active volcanoes of the Kuril Islands. The early stage of the 2009 eruption was recorded on June 12 from the International Space Station. (Photo by NASA):

3

Klyuchevskaya Sopka, Russia

Klyuchevskaya Sopka (Klyuchevskoy volcano) is an active stratovolcano in the east of Kamchatka. With a height of 4,850 m, it is the highest active volcano on the Eurasian continent. The age of the volcano is approximately 7,000 years. (Photo by NASA):

4

Volcano Klyuchevskaya Sopka. (Photo by NASA):

5

Pavlova Volcano, Alaska

Pavlova Volcano is an active stratovolcano near the southern tip of the Alaska Peninsula. The diameter of the volcano is about 7 km. It is one of the most active volcanoes in Alaska, with over 40 historical eruptions to its credit. The last major volcanic eruption occurred in 2013. (Photo by NASA | ISS Crew Earth Observations):

6

Puyehue, Chile

Puyehue is an active volcano in southern Chile. The height above sea level of the peak is 2,236 m. On June 4, 2011, several small tremors occurred in the region of the volcano, and an eruption began in the evening. A huge column of smoke and ash rose over the Puyehue volcano. A cloud of volcanic ash is blown by the wind towards Argentina. According to the National Service of Geology and Mining of the country, the volcano threw out a column of ash up to 10 km high. (Photo by NASA | GSFC | Jeff Schmaltz | MODIS Land Rapid Response Team):

7

Eyjafjallajökull volcano eruption, Iceland

A volcanic eruption near the Eyjafjallajökull glacier in Iceland began on the night of March 20/21, 2010. The main consequence of the eruption was the release of a cloud of volcanic ash, which disrupted air traffic in Northern Europe. (Photo by NASA | GSFC | Jeff Schmaltz | MODIS Land Rapid Response Team):

8

Volcano Nyiragongo, Congo

Since 1882, 34 eruptions have been recorded; it also happened that volcanic activity continued continuously for many years. The main crater of the volcano is 250 meters deep and 2 km wide; it sometimes forms a lake of lava. One of the most violent eruptions of Nyiragongo occurred in 1977; then several hundred people died from fiery streams. (Photo by NASA):

9

Shin Moedake Volcano, Japan

Following a powerful earthquake, the Shin-Moedake volcano woke up in Japan. It is located in the southwest of the country - on the island of Kyushu. The volcano threw piles of stones into the sky, and a giant cloud of ash formed over the mountain. (Photo by NASA | Jeff Schmaltz | MODIS Rapid Response Team):

10

Mount Merapi, Indonesia

Merapi is the largest active volcano in Indonesia, located on the island of Java near the city of Yogyakarta. Height 2914 meters. Major eruptions occur on average every 7 years. One of the most destructive eruptions was recorded in 1673, when several cities and many villages at the foot of the volcano were destroyed. (Photo by NASA):

11

Api Volcano, Indonesia

Api is one of the most active active volcanoes in Indonesia on Sangeang Island. The height of the volcano is 1949 meters. (Photo by NASA):

12

Mount Etna, Italy

Etna is an active stratovolcano located on the east coast of Sicily. It is the highest active volcano in Europe. Now the height of Etna is 3329 m above sea level. Etna is the largest active volcano in Italy, exceeding its closest "rival" Vesuvius by more than 2.5 times. According to various sources, Etna has from 200 to 400 lateral volcanic craters. On average, once every three months, lava erupts from one or another crater. (Photo by NASA):

13

Volcano Manam, Papua New Guinea

A large eruption of the Manam volcano occurred on the morning of January 12 north of New Guinea. Volcanologists report that in satellite images, the height of ash emissions reaches 14 kilometers. (Photo NASA | Jesse Allen):

14