Volcanoes are ... How does a volcanic eruption occur? Interesting facts about volcanoes

It is difficult to find a person who at least would not have taken an interest in volcanoes. Most of them read books about them, watched frames from eruptions with a sinking heart while admiring the power and splendor of the elements and rejoicing that this does not happen next to them. Volcanoes are something that does not leave anyone indifferent. So what is it?

The structure of the volcano

Volcanoes are special geological formations that arise when the mantle is raised from the depths of a red-hot substance and exits to the surface. Magma rises up the cracks and faults in the earth's crust. Where it breaks out, active volcanoes are formed. This occurs at the boundaries of the lithospheric plates, where faults arise due to their spreading or collision. And the plates themselves are involved in movement when the substance of the mantle is moved.

Most often, volcanoes look like conical mountains or hills. In their structure, the vent is clearly distinguished - the channel through which magma rises, and the crater is a depression at the top through which lava flows out. The volcanic cone itself consists of many layers of activity products: frozen lava, volcanic bombs and ash.

Since the eruption is accompanied by the ejection of hot gases, even during the day, and ash, volcanoes are often called "fire-breathing mountains". In ancient times they were considered a gateway to the underworld. And they received the name in honor of the ancient Roman god Vulcan. It was believed that fire and smoke flew out of its underground smithy. Such interesting facts about volcanoes warm up curiosity among the most diverse people.

Types of volcanoes

The existing division into existing and extinct is rather conditional. The active volcanoes are those that erupted in the memory of mankind. Evidence of eyewitnesses has been preserved about these events. A lot of active volcanoes in the areas of modern mountain building. This, for example, Kamchatka, the island of Iceland, East Africa, the Andes, the Cordillera.

Extinct volcanoes are not erupting for millennia. In the memory of people, there was no information about their activity. But there are many cases when a volcano, which was considered to be inactive long ago, suddenly woke up and brought many misfortunes. The most famous of them - the famous eruption of Vesuvius in 79, glorified Briullov's painting "The Last Day of Pompeii." Five years before this catastrophe, the rebellious Gladiators of Spartacus were hiding on its summit . And the mountain was covered with lush vegetation.

To the extinct volcanoes is Mount Elbrus - the highest peak in Russia. Its double-headed vertex consists of two cones fused with bases.

Volcanic eruption as a geological process

An eruption is the process of ejection of hot magmatic products on the earth's surface in a solid, liquid and gaseous state. For each volcano it is individual. Sometimes the eruption is quite calm, the liquid lava flows and flows down the slopes. It does not interfere with the gradual release of gases, so there are no strong explosions.

This type of eruption is characteristic of 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 occasionally clogs the crater. As a result, the evolved gases, without finding an outlet, accumulate in the vole of the volcano. When the pressure of the gases becomes very high, a powerful explosion occurs. He raises large volumes of lava, which subsequently falls to the ground in the form of volcanic bombs, sand and ash.

The most famous explosive volcanoes are already mentioned Vesuvius, Kathmai in North America.

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

Modern volcanoes

It is believed that there are more than 500 active volcanoes in the world today. Most of them belong to the zone of the Pacific "fire ring", located along the boundaries of the lithosphere plate of the same name. Each year, there are about 50 eruptions. At least half a billion people live in the zone of their activity.

Volcanoes of Kamchatka

One of the most famous areas of modern volcanism is in the Russian Far East. It is a region of modern mountain building, belonging to the Pacific ring of fire. 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 monuments of nature.

It is here that the highest active volcano in Eurasia - Klyuchevskaya Sopka is located. Its height is 4750 m. Plosky Tolbachik, Mutnovskaya Sopka, Gorely, Vilyuchinsky, Mountain Tooth, 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 volcanoes. But here are some interesting facts. Many things are known about volcanoes of Kamchatka. But in fact, along with this region is known for a much more rare phenomenon - geysers.

These are sources that periodically throw out fountains of boiling water and steam. Their activity is related to magma, which has risen through cracks in the earth's crust close to the earth's surface and heating underground waters.

The famous Valley of Geysers, located here, was opened in 1941 by TI Ustinova. It is rightfully considered one of the wonders of nature. The area of the Valley of Geysers is not more than 7 square kilometers. Km, but it operates 20 large geysers and dozens of sources of boiling water. The largest - geyser Giant - throws a column of water and steam at a height of about 30 m!

What is the highest volcano?

To define this is not so simple. 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, the volcano that was considered extinct can wake up. If it is high enough, it can push back the already existing leader.

Thirdly, how to calculate the height of the volcano - from the ground or from the sea level? This gives completely different figures. After all, the cone, which has the greatest absolute height, may not be the largest in comparison with the surrounding terrain, and vice versa.

Currently, among the active volcanoes, the largest is Ljuyllyaylako in South America. Its height is 6723 m. But many volcanologists believe that the title of the greatest can claim Cotopaxi, located on the same continent. Let his height be less - "only" 5897 m, but he had the last eruption in 1942, and at Ljuyllyaylako - already in 1877.

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

Mud volcanoes

Did anyone hear about the Volcano Valley in the Crimea? After all, it is very difficult to imagine this peninsula shrouded in smoke of eruptions, and the beaches - filled with red-hot lava. But you can not worry, because it's about mud volcanoes.

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

The process can last several days, accompanied by a local earthquake, an underground buzz. As a result, a low cone of frozen mud forms.

Mud volcanism areas

In the Crimea, such volcanoes are found on the Kerch Peninsula. The most famous of them is Jau-Tepe, which terribly frightened the locals with its short eruption (only 14 minutes) in 1914. A column of liquid mud was emitted 60 meters upwards. The length of the mud flow reached 500 m and a width of more than 100 m. But such large eruptions are more likely an exception.

The areas of action of mud volcanoes often coincide with the places of oil and gas extraction. In Russia, they are found on the Taman Peninsula, on Sakhalin. Azerbaijan is "rich" from neighboring countries.

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

Interesting facts about volcanoes

Edinburgh Castle in Scotland is erected on top of an extinct volcano. And most Scots do not even know it.

It turns out that volcanoes can be actors! In the film "The Last Samurai" Taranaki played the role of the sacred mountain of the Japanese Fujiyama, considered the most beautiful in New Zealand. The fact is that the surroundings of Fuji with its urban landscapes were not suitable for shooting the picture of the events of the late 19th century.

In general, New Zealand volcanoes do not have to complain about the negligence of filmmakers. Indeed, Ruapehu and Tongariro became known largely thanks to the film "The Lord of the Rings", in which he portrayed Orodruin, in whose flame the Ring of All-Power was created and subsequently destroyed there. A lonely mountain in Erebor in the film "The Hobbit" is also one of the local volcanoes.

And the Kamchatka geysers and waterfalls became the backdrop for the filming of the film "The Land of Sannikov."

The eruption of St. Helens volcano (USA) in 1980 is considered the most powerful in the entire 20th century. The explosion, in its capacity equal to 500 bombs dropped on Hiroshima, fell ash on the territory of four states.

The Icelandic volcano Eyyafyadlayokudl became famous for the fact that emissions of ash and smoke plunged the air flights of European countries into chaos in the spring of 2010. And his name confounded hundreds of radio and television broadcasters.

Filipino volcano Pinatubo erupted for the last time in 1991. At the same time, two American military bases were destroyed. And after 20 years the Pinatubo crater was filled with rainwater, forming a surprisingly beautiful lake, the slopes of the volcano overgrown with tropical vegetation. This enabled the travel agencies to organize recreation with swimming in a volcanic lake.

As a result of eruptions, interesting rocks are often formed. For example, the easiest stone is pumice stone. Numerous air bubbles make it lighter than water. Or meet in Hawaii "hair Pele." They are long, thin strands of rock. Many buildings in the capital of Armenia Yerevan are built of pink volcanic tuff, which gives the city a unique color.

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