What's inside the volcano. The formation of rocks of volcanic origin, basalt and tuff. What is a volcano crater

Sometimes, during a volcanic eruption, a scorching cloud can be formed, consisting of hot gases, ash, pumice and volcanic rocks.

Of all the volcanic processes, this is the most dangerous.
For example, the Mont-Pele volcano on the island of Martinique (Caribbean) with its scorching clouds destroyed 40,000 people in 1902 and completely destroyed the city of Saint-Pierre. In two minutes at a speed of 160 km / h, the scorching cloud passed through the city and all of its 40,000 inhabitants were dead. The walls of the houses were turned and destroyed, large trees were uprooted.

If the top of the volcano is covered with ice and snow, then during the eruption of the volcano the ice and snow melt, forming volcanic mud flows - lahars. Going down the slopes of the volcano, the mud-stone stream sweeps away everything in its path and covers the surroundings with a thick layer of volcanic rocks.
The speed of these flows can reach 90 km / h, and the distance they cover reaches 160 km. The famous eruption of Vesuvius in the year 79 AD buried the city of Pompeii under a thick layer of ash. Another city, Herculaneum, was flooded with mud flows caused by heavy rains that eroded heavy ash deposits. When the mud froze, the city of Herculaneum was firmly “concreted” under a layer deeper than the layer of ash that covered Pompeii.

10 most active volcanoes

Lesson plan:

• A bit of history

• What is a volcano?

• Volcano structure

• Types of volcanoes

• The value of volcanoes in nature

• Quiz "Volcanoes"

What are volcanoes?

• geological formations on the surface of the earth's crust or the crust of another planet, where magma comes to the surface, forming lava, volcanic gases, stones (volcanic bombs) and pyroclastic flows.

• The word "Volcano" comes from the name of the ancient Roman god of fire Vulcan.

• The science that studies volcanoes is volcanology, geomorphology.

What is volcanism?

Volcanism is complex.

the process by which

magma rises

from the depths of the earth, breaks through

  crust and

poured onto the surface

Volcanic eruption products

• Carbon dioxide

• Hydrogen sulphide

• Water vapor

• Lava

• Volcanic bombs

• Volcanic ash

Volcanoes are classified

• in form(thyroid, stratovolcanoes, slag cones, dome),

• activity   (acting, sleeping, extinct),

• location   (ground, submarine, subglacial)

Krakatau Island Change

Thyroid Volcanoes formed as a result of repeated emissions of liquid lava. This form is typical for volcanoes spewing low viscosity basaltic lava: it flows both from the central crater and from the slopes of the volcano. Lava spreads evenly for many kilometers. Like, for example, on the volcano Mauna Loa in Hawaii, where it flows directly into the ocean.

• Slag cones only loose substances such as stones and the ashes   : the largest fragments accumulate in layers around the crater. Because of this, the volcano with each eruption is getting higher. Light particles fly off for a longer distance, which makes the slopes gently sloping.

• Stratovolcanoes, or "layered volcanoes",periodically spew lava and pyroclastic substance - a mixture of hot gas, ash and hot stones. Therefore, the deposits on their cone alternate. On the slopes of stratovolcanoes ribbed corridors of frozen lava form, which serve as a support for the volcano.

• Dome volcanoes formed when granite, viscous magma rises above the edges of a volcanic crater and only a small amount seeps out, flowing down the slopes. Magma clogs the mouth of a volcano, like a cork, which the gases that have accumulated under the dome literally knock out the mouth.

• Operating

• Sleeping

• Extinct

Klyuchevskaya Sopka - active volcano

Hekla - active volcano

Vesuvius

Pinatubo

Elbrus - sleeping volcano

Demovend - extinct volcano

Than

dangerous

active volcanoes?

The last day of Pompeii. Bryullova

Value of volcanoes

• The formation of rocks of volcanic origin, basalt and tuff.

2. The formation of warm and mineral springs

3. A power station operates in Kamchatka using steam that rises through wells from great depths.

fastening

fastening

What is lava?

What is a volcano crater?

What is a mouthpiece?

  Name products

  Name products

  volcanic eruptions?

  What types of volcanoes

  you know?

Show on the map:

Volcano vesuvius

Volcano

Kilimanjaro

Show on the map:

Volcano

Klyuchevskaya Sopka

Volcano

Krakatau

On contour map   cause all volcanoes,

which are mentioned in the text of the textbook,

Volcanoes are geological formations on the surface of the Earth, where magma comes out in the form of lava. These mountains are not only on Earth, but also on other planets. So, the volcano Olympus on Mars reaches a height of several tens of kilometers. Such formations are dangerous not only by lava, but also by the release into the atmosphere of a large amount of dust and ash.

The eruption of the Icelandic volcano Eyjafyallayekyul in 2010 caused a lot of noise. It may not have been the most destructive in strength, but its proximity to Europe led to the impact of emissions on the continent's transport system. However, history knows many other cases of the destructive effects of volcanoes. We will tell about ten most known and scale of them.

On August 24, 79, the eruption of Mount Vesuvius erupted, which destroyed not only the well-known city of Pompeii, but also the cities of Stabiae and Herculaneum. Ash even flew to Egypt and Syria. It would be a mistake to assume that the catastrophe destroyed Pompeii alive, out of 20 thousand people only 2 thousand died. Among the victims was the famous scientist Pliny the Elder, who approached a volcano on a ship in order to investigate it and was thus almost at the epicenter of the disaster. During the excavations of Pompeii, it was discovered that the city’s life at the time of the disaster had frozen under a multi-meter layer of ash - objects, houses with furniture, remained in their places, people and animals were found. Today, Vesuvius remains the only active volcano in the continental part of Europe, more than 80 of its eruptions are known, the very first one happened presumably 9 thousand years ago, and the last happened in 1944. Then the cities of Massa and San Sebastiano were destroyed, and 57 people died. At 15 kilometers from Vesuvius, Naples is located, the height of the mountains is 1281 meters.

The cataclysm on this Indonesian island happened on April 5, 1815. This is the largest in terms of the number of people killed and the amount of ejected material in modern history. The catastrophe associated with the eruption, and the ensuing famine killed 92 thousand people. In addition, the Tambor culture, which the Europeans had just met shortly before, completely disappeared from the face of the earth. The volcano lived 10 days, decreasing in this time in height by 1400 meters. Ashes for 3 days hid a territory within a radius of 500 kilometers from the sun. According to the testimony of the British authorities in those days in Indonesia it was impossible to consider anything at arm's length. Most of the island of Sumbawa was covered with a meter layer of ash, under the weight of which even stone houses were scattered. 150-180 cubic kilometers of gases and pyro-classics were emitted into the atmosphere. The volcano therefore had a strong impact on the climate of the entire planet - ash clouds badly let the sun's rays through, which led to a noticeable decrease in temperature. The year 1816 became known as the "year without summer", in Europe and America the snow melted only in June, and the first frosts appeared as early as August. As a result, there were massive crop failures and famine.

27 thousand years ago on one of the islands occurred severe eruption volcano, superior in strength even Tambora. Geologists believe this cataclysm is the last such force in the history of the planet. As a result of the work of the supervolcano, Lake Taupo was formed, which today is the object of attention of tourists, as it is very beautiful. The last eruption of the giant took place in 180 AD. Ash and the blast wave destroyed half of all life on the North Island, about 100 cubic kilometers of tectonic matter fell into the atmosphere. The eruption rate of the rock was 700 km / h. Ashes ascending into the sky dyed purple sunsets and sunrises around the world, as reflected in the ancient Roman and Chinese chronicles.

The volcano, located between the islands of Sumatra and Java, produced on August 27, 1883, the largest explosion of its kind in modern history. In the course of the cataclysm, a tsunami with a height of up to 30 meters arose, with which 295 villages and cities simply washed away, killing about 37 thousand people. The roar of the explosion was heard on 8% of the entire surface of the planet, and pieces of lava were ejected into the air to an unprecedented height of 55 kilometers. The wind blew so much volcanic ash that after 10 days it was discovered at a distance of 5330 kilometers from the scene. The mountain-island after this split into 3 small parts. The wave from the explosion rounded the earth from 7 to 11 times, geologists believe that the explosion was 200 thousand times stronger than a nuclear attack on Hiroshima. Krakatau had previously woken up, so, in 535, its activity noticeably changed the climate of the planet, perhaps then the islands of Java and Sumatra were divided. At the site of a volcano destroyed in 1883 during an underwater eruption in 1927, a new volcano appeared, Anak Krakatau, which is still quite active today. Its height is now at the expense of new activities already 300 meters.

Approximately one and a half thousand years BC, on the island of Fera, a volcanic eruption occurred, which put an end to the whole Cretan civilization. Sulfur covered all the fields, which made further farming unthinkable. According to some versions, it is Fehr that is the very Atlantis described by Plato. Someone thinks that the eruption of Santorin was included in the chronicles, like a pillar of fire seen by Moses, and the parting sea was nothing but the consequences of the departure of the island of Fera to the water. However, Vulkan continued its activities, in 1886 its eruption lasted a whole year, while pieces of lava flew straight from the sea and rose to a height of 500 meters. As a result - several new islands nearby.

About 200 eruptions of this Italian volcano are known. Some of them were quite powerful, for example, in 1169 about 15 thousand people died during the cataclysm. Today, Etna remains an active volcano with a height of 3,329 meters, waking up about once every 150 years and destroying one of the nearby villages. Why do people not leave the slopes of the mountain? The fact is that the frozen lava helps the soil to become more fertile, which is why the Sicilians settle here. In 1928, moreover, a miracle happened - the flow of red-hot lava stopped in front of a Catholic procession. This so inspired the believers that in 1930 a chapel was erected at this place, 30 years later, the lava stopped before it. Italians protect these places, so in 1981 a reserve was created around Etna by the local government. It is curious that on a quiet volcano even a blues music festival is held. Etna is quite large, exceeding the size of Vesuvius in 2.5 times. The volcano has from 200 to 400 side craters, every three months lava erupts from one of them.

The eruption of the volcano on the island began in April 1902, and on May 8 a whole cloud of vapors, gases and hot lava struck the city of Saint-Pierre, located 8 kilometers away. A few minutes later he was gone, and of the 17 ships that were at that moment in the harbor, only one managed to survive. The ship "Roddam" escaped from the clutches of the elements with broken masts, smoking and littered with ashes. Of the 28 thousand who inhabited the city, two were saved, one of them was called Oposte Siparis, and he was sentenced to death. He was saved by the thick stone walls of the prison. Subsequently, the prisoner was pardoned by the governor, having spent the rest of his life traveling around the world with stories about what happened. The force of the blow was such that the monument on the square, weighing several tons, was thrown aside, and the heat was such that even the bottles melted. Interestingly, the outpouring of liquid lava did not occur immediately, vapors, gases and sprayed lava struck. In the future, a sharp lava block with a height of 375 meters emerged from the volcano vents. It also turned out that the bottom of the sea near Martinique dropped to several hundred meters. The city of Saint-Pierre, by the way, was famous for the fact that Napoleon’s wife, Josephine Beauharnais, was born in it.

A volcano with a height of 5400 meters, located in the Andes, splashed lava flows on November 13, 1985, and the main attack fell on the city of Armero, located 50 kilometers away. In just 10 minutes it took lava to destroy it. The death toll exceeded 21 thousand people, and all at that time about 29 thousand lived in Armero. Sadly, no one listened to the information to the volcanologists about the impending eruption, as the information of the specialists was not repeatedly confirmed.

Until June 12, 1991, the volcano for 611 years was considered extinct. The first signs of activity appeared in April and the Philippine authorities managed to evacuate all residents within a radius of 20 kilometers. The very same eruption claimed the lives of 875 people, while the United States naval base and the American strategic air base, located 18 kilometers from Pinatubo, were destroyed. Ejected ash covered a section of the sky of 125,000 km2. The consequences of the catastrophe were a general decrease in temperature by half a degree and a reduction in the ozone layer, due to which a very large ozone hole formed over Antarctica. The height of the volcano before the eruption was 1,486 meters, and after - 1,745 meters. At the site of Pinatubo, a crater of diameters of 2.5 kilometers was formed. Today in this area regularly occur tremorsimpeding any construction within a radius of tens of kilometers.

The eruption of this volcano on June 6, 1912 was one of the largest in the 20th century. The height of the ash column was 20 kilometers, and the sound reached the capital of Alaska, Juneau, located 1,200 kilometers away. At a distance of 4 kilometers from the epicenter, the ash layer reached 20 meters. Summer in Alaska turned out to be very cold, because the rays could not break through the cloud. After all, thirty billion tons of rocks were understood in the air! In the same crater formed a lake with diameters of 1.5 kilometers, it became the main attraction formed here in 1980 National Park   and reserve Katmay. Today is the height of this active volcano   2047 meters, and the last known eruption   happened in 1921.