Volcanoes are How is a volcanic eruption? Interesting facts about volcanoes

It is difficult to find a person who at least once would not be interested in volcanoes. Most read books about them, with bated breath watched footage from the places of eruptions, at the same time admiring the power and magnificence of the elements and rejoicing that this did not happen next to them. Volcanoes - this is what leaves no one indifferent. So what is it?

Volcano structure

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

Most often, volcanoes look like conical mountains or hills. In their structure, a vent — the channel through which magma rises, and a crater — a depression at the top through which the outflow of lava occurs, are clearly distinguished. The volcanic cone itself consists of many layers of activity products: solidified lava, volcanic bombs 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 the name in honor of the ancient Roman god Vulcan. It was believed that fire and smoke were flying from his underground forge. Such interesting facts about volcanoes fuel the curiosity of a wide variety of people.

Types of Volcanoes

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

Extinct volcanoes are not erupted for millennia. Information about their activity has not been preserved in people's memory. But there are many cases when a volcano, which had long been 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 rebellious gladiators of Spartak were hiding on its top. And the mountain was covered with lush vegetation.

Mount Elbrus, the highest peak in Russia, belongs to extinct volcanoes. Its two-headed peak consists of two cones, merged with the bases.

Volcanic eruption as a geological process

An eruption is the process of releasing incandescent igneous 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, liquid lava flows 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 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, not finding a way out, accumulate in the vent 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, Kathmay 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 break through, occurred in 1883. Then the volcano Krakatau lost most of its part. A column of gas and ash rose up to 70 km. The contact of ocean water with red-hot magma led to the formation of tsunamis up to 30 m high. In total, about 37 thousand people became victims of the eruption.

Modern volcanoes

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

Volcanoes of Kamchatka

One of the most famous areas of modern volcanism is located in the Russian Far East. This is the area of ​​modern mountain building related 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 natural monuments.

It is here that the highest active volcano in Eurasia is located - Klyuchevskaya Sopka. Its height is 4750 m. Flat Tolbachik, Mutnovskaya Sopka, Gorely, Vilyuchinsky, Mountain Tooth, Avachinsky Sopka and others are also widely known for their activity. In total, there are 28 active volcanoes and about 500 extinct volcanoes in Kamchatka. But here are some interesting facts. A lot is known about the volcanoes of Kamchatka. But along with this region is known for a much rarer phenomenon - geysers.

These are springs that periodically throw fountains of boiling water and steam. Their activity is associated with magma that has risen along cracks in the earth’s crust close to the earth’s surface and heats groundwater.

The famous Valley of Geysers located here was discovered in 1941 by T. I. Ustinova. She is rightfully considered one of the wonders of nature. The area of ​​the Valley of Geysers is not more than 7 square meters. km, but it has 20 large geysers and dozens of springs with boiling water. The largest - Geyser Giant - throws a column of water and steam to a height of about 30 m!

Which volcano is the highest?

Defining 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, an extinct volcano may wake up. If he is tall enough, he can push back an 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 having the greatest absolute height may not be the largest in comparison with the surrounding area, and vice versa.

Currently, among the active volcanoes, the largest is considered Ljulyayaylyako in South America. Its height is 6723 m. But many volcanologists believe that Cotopaxi, located on the same mainland, can claim the title of greatest. Let him have a height less - “only” 5897 m, but he had the last eruption in 1942, and Lyuilyaylyako - already in 1877.

Also the highest volcano on Earth can be considered the Hawaiian Mauna Loa. Although its absolute height is 4169 m, it is less than half its true size. The Mauna Loa cone starts from the ocean floor and rises more than 9 km. That is, its height from the sole to the top exceeds the size of the 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 smoke of eruptions, and beaches - flooded with red-hot lava. But you can not worry, because we are talking about mud volcanoes.

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

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

Mud Volcanism Areas

In Crimea, such volcanoes are found on the Kerch Peninsula. The most famous of them is Jau-Tepe, who terrified the locals with his short eruption (only 14 minutes) in 1914. A column of liquid mud was thrown up 60 meters. The length of the mud stream reached 500 m with 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 production. In Russia, they are found on the Taman Peninsula, on Sakhalin. From neighboring countries, Azerbaijan is "rich" in them.

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