The study of the features of volcanoes, the phenomenon of volcanism is engaged in volcanologists and geomorphologists.

Structure: hearth, vent, crater. Hearth - a place in earth crust or gowns. A vent is a channel through which magma rises. Crater - hole, funnel, bowl on the top of a volcano mountain.

Volcanoes are classified by location, shape and activity.

By activity: extinct, dormant, active. This classification is rather arbitrary. The extinct ones have not erupted for more than 1000 years: they retain their general shape, the crater and slopes undergo changes. Sometimes they are active. Example: Mont Pele in Martinique, Valley of Volcanoes in Buryatia, Kalara volcanoes.

Sleepers are volcanoes in which the likelihood of eruption is higher than that of extinct ones. Some of them are called supervolcanoes - Toba in Sumatra, Taulo in New Zealand, volcanoes in Kamchatka.

Active ones are the main object of interest of volcanologists, they erupt frequently. They are located in the belts of young mountains, where mountain building continues. There is no consensus among scientists on how to accurately classify these geological formations. The most active volcanism: South and Central America, Hawaii, Japan, the Sunda Islands.

They are classified by location: subglacial, terrestrial, underwater. The types are distinguished according to the shape: dome, cinder cone, thyroid, stratovolcano, complex species.

Based on overall design distinguish formations of the central and linear types. The former have a central channel through which lava comes to the surface. The second type is fissure, the channels through which the lava rises have an elongated shape. Scientists distinguish the areal type, but there are no such ones on Earth, at least in our time. They are believed to have existed when the planet was forming.

The eruption is considered an emergency, a disaster. It can be an hour, a month, a year, several years. The consequences of the eruption: the formation of depressions, calderas, geysers, fumaroles. Low mountains and islands may appear. Lakes are formed in the craters.

Types of eruption: Hawaiian (basalt lava comes to the surface, accompanied by smoky clouds, fire avalanches), hydroexplosive (a lot of steam is released, confined to water bodies).

A mud volcano is a formation, as a result of the activity of which mud, gases, and not magma, come to the surface. They are found on the territory of Russia, Central Asia.

The largest formations: San Pedro, Cotopaxi, Ojos del Salado in the Andes, Elbrus in the Caucasus, Fujiyama in Japan, Etna and Vesuvius in Italy, Klyuchevskaya Sopka in Kamchatka.

Fixed not only on Earth. If on other planets of the solar system and their satellites.

• Volcanic eruptions remind us of the formidable and indomitable forces that are hidden in the bowels of the Earth.

• The mystery of the causes of volcanism has always aroused fear and keen interest in people, and the tragic consequences of eruptions forced them to explore this element.

• Volcano formation

• When a magma chamber is formed in the bowels of the Earth, molten liquid magma presses down on the tectonic plate with such force that it begins to crack. Along the cracks and faults, magma rushes upward, melting the rock and expanding the cracks. This forms the excretory canal. It passes in the center of the volcano, through which molten magma pours out from the crater of the volcano in the form of fiery liquid lava. The products of the eruption - pumice, lava, tuff - settle on the slopes of the volcano, forming a cone. At the top of the volcano there is a depression - a crater. At the bottom of the crater, you can see the mouth of the volcano - the opening of the outlet channel through which ash, hot gases and water vapors, lava and rock fragments are spewed out. The vents of the volcano can be gaping - empty or filled with molten lava. If the lava solidifies in the vent, then a solid plug is formed, which can only be broken by a strong volcanic eruption, and a powerful explosion occurs.

• Types of volcanoes

• Active volcanoes

• Volcanoes occasionally spew molten rock, ash, gases, and rocks. This is because deep below them there is a magma chamber, similar to a huge furnace, in which the rock melts, turning into fiery liquid lava.

• Those volcanoes are also considered active if there is any evidence of their eruptions in the history of mankind.

• Extinct volcanoes

• Extinct volcanoes were active only in prehistoric times. The hearth under them has long died out, and they themselves are so badly destroyed that only the studies of geologists reveal traces of ancient volcanic activity.

• Dormant volcanoes

• Dormant volcanoes in historical time did not erupt, but at any moment their catastrophic eruption can begin, because the magma chamber under them has not died out. Dormant volcanoes show signs of life: they can smoke - smoke comes from their crater, gases and steam are released from cracks in the mountain, hot springs flow. The longer a dormant volcano is at rest, the more dangerous it is: the power of its explosive awakening can be catastrophic.

• Types of eruptions

• Explosive eruptions

• A volcanic explosion occurs when volcanic gases are released from thick magma. During such eruptions, the tops of the mountains are destroyed and millions of tons of ash are thrown into the sky to a great height.
• Ashes, gases and steam rise into the sky for tens of kilometers in the form of curly clouds.

• Effusive eruptions

• During an effusive volcanic eruption, liquid lava flows freely with the formation of lava flows and sheets

• Extrusive eruptions

• From the crater of the volcano, a huge amount of burning gases and hot lava dust is thrown out. Spreading around the volcano with great speed, this scorching cloud instantly burns out everything over a very large area.

• Eruption products

• Everything that comes out of the bowels of the Earth during volcanic eruptions is called eruption products.

• They are liquid, solid and gaseous.

• Lava is a liquid eruption product.

• Lava- this is magma poured onto the surface of the earth

• Lava flow types.

• It has a smooth or slightly wrinkled surface and is composed of liquid lava. When solidified, such lava forms a flat, smooth surface, sometimes with long wriggling wrinkles in the form of snakes and thick ropes - ropes. Often it is called “rope lava”.

• Has an uneven surface with cracks. This lava is very thick and viscous, so the flow moves slowly. When the lava begins to cool, it cracks into pieces, but they continue to move like clockwork on the incandescent lava that has not yet cooled down. The upper solidified layer of lava resembles piles of slag that is formed from the combustion of coal.

• Lava flow "ah-ah"

• Lava flow "pa-hoe-hoe"

• Pyroclasts

• The fragments of rocks that are scattered with gases during volcanic eruptions are called pyroclasts

• Volcanic gases

• Volcanic phenomena are associated with the action of gases. If the magma is very liquid, gases are released unhindered and do not threaten explosions. Gases can foam even viscous magma, forming a porous pumice stone, pulverize magma into small particles - volcanic ash and sand - and, combining with them, form a deadly scorching cloud.
• And finally, gases can scatter rock debris from the volcano's mouth for hundreds of meters.

• Volcanoes in Kamchatka

• Volcano Nameless

• Bezymyanny volcano is located near Klyuchevaya Sopka. He was considered extinct, and the power of his awakening was enormous. On March 30, 1956, a terrible explosion took down all upper part volcano. Ash clouds shot up almost 40 km, from

• a powerful jet of hot gas, volcanic sand and ash burst out, which burned out all vegetation for 25 km around the volcano. A lava dome began to grow from the craters. Now the base of this dome is 750 m, and the height is 320 m. Fortunately, despite all the fury of the eruption, no one died - not a single living soul was in the hours of the eruption within a radius of 45 km from the volcano.

• Tolbachinskaya Sopka

• Volcano Tolbachik is a very active volcano. At its summit, 3085 m high, there was a huge caldera with a crater 300 m in diameter and 150 m deep. From time to time a small lake of hot lava appeared in the crater. In 1975-1976, an Icelandic-type fissure eruption took place. It lasted 520 days continuously.

• In a very short time, many cracks more than a kilometer long were formed. All this was accompanied by the spilling and gushing of lava. During the eruption of Tolbachik from the depths of the Earth, two cubic km of volcanic products were thrown to the surface. This is the largest known volcanic eruption in Kamchatka and the Kuril Islands.

• Volcano in the Philippines

• Mayon volcano, the most active on the island of Luzon. On October 23, 1776, it caused the death of 2,000 people when a huge amount of lava was thrown out of its crater.

• Mayon volcano

• The longest Mayon eruption was observed in 1897. It lasted from 23 to 30 June and claimed 400 lives.

• Volcanoes of the Mediterranean

• Stromboli volcano

• In the south of Italy, near the island of Vulcano. The island is the volcano Stromboli. It has a very restless character, and it has been operating for several millennia almost without interruption. From time to time, explosions occur in its crater, and hot slag and volcanic bombs fly upwards for tens, and sometimes hundreds of meters, but lava usually does not flow from it.

• One of the most powerful eruptions of Stromboli was noted in 1930, and at the beginning of the fifteenth century there were already seven of them.

• Volcanoes of the Atlantic

• In the south of Iceland is the volcanic Laki mountain range, which contains more than a hundred cones.
• The ridge reaches 818 m in height and 25 km in length.

• June 8, 1783.
• Not far from the town of Vatnajo-kull in the southeast of Iceland, a powerful eruption of the Laki volcano began. It lasted 8 months, the length of the flow of the escaped lava was almost 70 kilometers, and the volume of this mass, moving at a speed of over 45 km / h, was equal to 12,000 cubic meters and occupied an area of \u200b\u200b579 square kilometers.

• Lucky volcano

• Volcanoes of Africa

• Kilimanjaro volcano

• Kilimanjaro is a volcanic mountain range in eastern Africa
• The massif consists of three peaks - Kibo, Mawenzi and Shira. The volcanoes Mawenzi and Shira have long gone extinct, and Kibo continues to smoke with volcanic gases through holes on the slopes.

• Volcanoes of the Pacific Ocean

• Volcano st helens

• In North America, in the Cordilleras, Mount St. Helens is perhaps the lowest of any other peaks, at just 2950 meters.
• On March 20, 1980, four powerful tremors shook the area, and on March 27, 47 tremors with a force of up to three points. At noon of the same day, a deafening explosion was heard near the very top.
• This monstrous explosion took the lives of 62 people.

Working with a geographic map

• Show the following volcanoes on the map:
• Nameless, Tolbachinskaya Sopka, Mayon, Stromboli, Laki, Kilimanjaro, St. Helens
• Show on the map the volcanoes that have erupted over the past year

• Questions about the material covered

• 1. What are the volcanoes?

• 3. What types of eruptions do you know?

• 5. What are the products of the eruption?

• 2.How are volcanoes formed?

• 4. Give a brief description of each type of eruption.

Volcanoes presentation was prepared by a pupil of the 5-A class of the Moscow State Educational Institution "Secondary School No. 16" Ivan Ershov Head: Mostovaya Alla Nikolaevna

Volcanoes are the name of the ancient god of fire, the patron saint of blacksmithing. According to myths, his forge was in the bowels of the earth, and smoke and flames from it came out through the crater of Mount Etna.

The ancient Greeks considered volcanoes to be the forge of the god Hephaestus and treated them with great reverence.

If a crack appears in the earth's crust, a hot, molten substance - magma - rises along it from the depths of the planet, under tremendous pressure.

The ancient Romans feared the unpredictable anger of volcanoes. On August 24, 79, the Roman cities of Pompeii, Herculaneum and Stabia were destroyed in the eruption of Vesuvius

If magma is poured onto the surface of the Earth, hot gases burst out of it, and it is already called lava.

The cooled lava forms an elevation around the cracks in the ground. It grows, turns into a mountain - a cone. This is how a volcano grows. There is a depression at its top - a crater.

Sometimes long years the volcano "sleeps" forget about it

cities grow on its slopes

Volcanoes are divided into: active, erupting at the present time, constantly or periodically; asleep, about the eruptions of which there is no information, but they retained their shape and local earthquakes occur under them; extinct, heavily destroyed and eroded volcanoes without any manifestations of volcanic activity

Steam jets and gases rise from cracks on the bottom and walls of the crater. Sometimes they calmly come out from under stones and crevices, and sometimes they burst out with a whistle and hiss. For months and years, the volcano can quietly smoke until an eruption occurs. This event is often preceded by an earthquake; an underground rumble is heard, the release of vapors and gases intensifies, clouds thicken over the top of the volcano.

The volcano wakes up

eruption begins

eruption begins

View of an erupting volcano from an airplane

Eruptions are long-term (over several years, decades and centuries) and short-term (measured in hours). After a violent eruption, the volcano again comes to rest for several years and even decades.

Scientists are studying the volcano during the eruption

After the eruption, a scorched desert remains, and life will not appear on this place soon

Volcanic bombs are pieces of cooled lava thrown out during volcanic eruptions in a liquid or plastic state and have taken round, spindle-shaped and other forms.

There are over 800 active volcanoes on earth. Mount Etna Cotopaxi, Ecuador

We have about 70 of them in Russia. Karymsky Volcano Located in the central part of the Kamchatka volcanic belt. Nowadays, the Karymsky volcano is one of the most active in the world.

Maly Semyachik Volcano It is a part of the Karymsky group of volcanoes and is located 15 km north-east of the Karymsky volcano.

Volcanic eruptions also occur at the bottom of the seas and oceans.

Mariners learn about this when they suddenly see a column of steam above the water.

or “stone foam” floating on the surface - pumice.

Some underwater volcanoes form cones that protrude above the surface of the water in the form of islands.

Technological map Task 1

i want to know

What is a volcano ?

• Volcano - (from Latin vulcanus - fire, flame), a conical mountain, from the throat of which hot gases, steam, ash, rock fragments, as well as powerful streams of hot lava that spread over the surface of the earth are emitted.
• A volcano is a geological formation 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.
• Volcanoes are conical mountains composed of products of their eruption.

Technological map Task 2.

The volcano is …………………………………………………………………………………… ...

…………………………………………………………………………………………………… ...

………………………………………………………………………………………………… .....

Volcano structure

• A chamber of magma is a place under the earth's crust,

where magma is collected.

• The mouth of a volcano is a channel through which magma rises.
• The volcano crater is a bowl-shaped depression at the top of a mountain.
• Lava is an outpouring magma.

Technological map Task 3 Complete the scheme "The structure of the volcano"

Eruption - this is the release of molten matter of the earth's crust and mantle to the surface of the planet, called magma .

Historic volcanic disaster

K. Bryullov "The Last Day of Pompeii"

Causes of volcanic eruptions

Earthquake;

Pressure drop in the magma chamber. And with a sudden decrease in pressure, magma melts, gases expand and rush out.

Signs of a volcanic eruption

Almost always, a volcanic eruption is predictable. The most characteristic signs of the "awakening" of the volcano are:

• - increasing the release of gases and

mineral waters on its

• - temperature increase;
• - underground hum.

Types of volcanic eruptions

If gases are released from magma relatively calmly, then it pours out onto the surface, forming lava flows. Such an eruption was named effusive.

If the gases are released quickly, there is a kind of instant boiling up of the magmatic melt and it is bursting with expanding gas bubbles.

A powerful

explosive eruption,

which received

name explosive.

If the magma is very viscous and its temperature is low, then it is slowly squeezed out to the surface. Such an eruption is called extrusive.

Volcano types

Most common central volcanoes Is a hill, mountain or hill with a depression at the top – crater , from which magma emerges to the surface. When a volcano erupts, discarded

debris from it,

ash, pouring lava

remain on its slopes.

The height of the mountain increases

xia, and with it the crater

moves higher and

Another type of volcano - linear, or fractured . Their occurrence is associated with the rise of liquid basaltic magma through a crack in the earth's crust. Liquid lava spreads over vast areas, forming lava sheets. Such a volcano looks like a crack on the surface of the Earth.

Active volcanoes

Krakatoa

Fujiyama

Klyuchevskaya Sopka

Extinct volcanoes

Kilimanjaro

TEST

1.Geological formation arising above channels and cracks in the earth's crust, through which ash, lava, hot gases, water vapor, and rock fragments are erupted onto the earth's surface

a) earthquake

b) seaquake

c) volcano

2. The word "volcano" comes from the name of the ancient Roman god:

a) the underworld

3. Find two causes of a volcanic eruption

a) flood

b) earthquake

c) pressure drop in the magma chamber

d) tsunami

4. Find three signs of a volcanic eruption

a) increased output of gases and mineral waters;

b) temperature rise;

c) underground hum.

d) lowering the temperature

5. Choose the wrong classification of volcanoes a) in shape b) in the amount of erupted lava c) in activity

d) by location

Answers to the test

3 - b, c

4 - a, b, c

Homework

Chapter 2, item 5, tasks from technological map Creative assignment:

(optional and optional)

make a model of the volcano;

make a selection of facts about the volcanic eruption