How do volcanoes erupt and how do volcanoes erupt?

Volcanic eruptions are a strong way of showing the energy released by magma, that is, when the magma energy in the interior of the earth accumulates to a certain extent, it will erupt along the weak areas of the earth's crust under strong pressure, forming a spectacular volcanic eruption. Volcanic eruptions can last for thousands of years, from short to long. Some have piled up volcanoes thousands of meters high on the ground, while others have created new islands in the ocean.

The Hawaiian Islands in the United States are volcanic islands where undersea volcanoes have erupted many times.

Volcanoes typically eject gases, lava, and solid eruptions. Volcanic eruptions eject from the crater, and most of them accumulate around the crater, forming a cone-shaped mountain called a volcanic cone. The material and intensity of the eruption are often related to the nature of the lava ejected by the volcano.

Acidic magma, which contains a lot of silica, is viscous and contains gas, and it is explosive. Magma with a large mafic component, less gas, good fluidity, and weak explosive power, often forming shield-shaped volcanic cones.

So, how exactly did a volcano erupt? We know that apples fall downwards on the ground, which is the effect of gravity. The upward movement of mantle material as magma in the ground does not violate this principle, and gravity also plays a role.

At the same time, the gas and water in the magma are also important driving forces for volcanic eruptions. Because the red-hot magma could not contain them, it was only because of the intense pressure in the depths of the earth that they were barely confused with magma. It's a bit like the carbonic acid in soda, which can dissolve into water under pressure, but if the pressure is reduced, they will separate, and the volume expands rapidly to produce a huge impact.

When the magma accumulates at the bottom of the volcano, some of the material gradually condenses into rock and separates from it, and the content of gas and water in the remaining material becomes higher and higher, and the impact force becomes stronger and stronger. When it breaks through the earth's crust, a large amount of magma will rush to the surface along the way out, and the pressure will drop sharply, and the gas and water will expand rapidly, exploding the surface like explosives to form a volcanic eruption.

Today, scientists divide volcanoes into three categories according to their activity: The first type is the volcanoes that have been regularly erupting periodically during human history, called active volcanoes. The second type is a volcano that has erupted before in human history, but has not re-erupted until today, called extinct volcanoes.

The third type is extinct volcanoes that have been extinguished for a long time and sometimes erupt suddenly, which is called dormant volcanoes.

Currently, there are about 2,000 extinct volcanoes and 500 active volcanoes on Earth. They are mainly found in the volcanic belts of the Pacific Rim, the Mediterranean, and East Africa, with uplifted volcanic belts at the bottom of the Atlantic Ocean. There are more than 600 volcanoes discovered in China today, and the vast majority of them are extinct volcanoes, such as the extinct volcanic group near Datong, Shanxi.

There are also a few volcanoes that are temporarily dormant, such as Baitou Mountain in Changbai Mountain and Wudalianchi in Heilongjiang Province. Only a few volcanoes have active in modern times, such as Qixing Mountain in Taiwan's Datun volcanic group, which constantly spits sulfur-containing gases and smoke; A volcano in the Kunlun Mountains near Yutian in Xinjiang erupted in 1951.

With a sneeze. or pull abnormal feces like that.

The principle of volcanic eruption: the magmatic material that forms a molten state deep underground, under the conditions of high temperature and high pressure, due to the movement of the earth's crust, the rock layer is fractured, resulting in the reduction of the pressure of the magma gathered in the ground, and the separation of gas and water vapor from it, resulting in volume expansion and propulsion of magma, along the fault to the ground, until it rushes out of the surface, forming volcanic eruptions with different types and scales of power.

The experimental principle of the volcanic eruption is due to a chemical reaction between baking soda and vinegar. But the chemistry of baking soda and vinegar does not represent the true principle of volcanic eruptions.

The real cause of volcanic eruptions is chemical and physical reactions.

Volcaniceruption, a geological term, is a peculiar geological phenomenon, a manifestation of the movement of the earth's crust and one of the most intense manifestations of thermal energy on the surface of the earth's interior. It is the release of ejecta such as magma from a crater to the surface in a short period of time.

Due to the large amount of volatiles contained in the magma, coupled with the confining pressure of the overlying rock layer, these volatiles are dissolved in the magma and cannot overflow, when the magma rises close to the surface, the pressure decreases, and the volatiles are released sharply, thus forming a volcanic eruption.

Eruption stage: ** of the gas.

In the gestation stage of volcanic eruption, due to the occurrence of gas dissolution and earthquake swarm, the degree of fracture of the overlying rock increases, the pressure decreases, and the gas dissolution in the magma increases, the magma volume gradually expands, the density decreases, and the internal pressure increases.

When the internal pressure greatly exceeds the external pressure, the gas is violently broken in the fracture density zone of the overlying rock, which breaks the rock and hits the channel of the mountain eruption, and the fragments are first ejected, followed by the eruption of magma.

Formation of eruption columns.

After the gas**, the gas ejects the cuttings and deep magma in the channel into the air with great ejection force, forming an eruption column. The eruption column can be further divided into three zones:

1.Air Punch Zone: It is located in the lower part of the eruption column, which is equivalent to one-tenth of the height of the entire eruption column. Because of the speed and force of the gas that comes out of the crater, it is thrown into the air even though the density of the ejected rocks and other materials far exceeds the density of the atmosphere.

The speed of the air rush gradually increases as it rises in the volcanic channel, and when it erupts from the surface and shoots into the air, its speed gradually decreases due to the pressure of the atmosphere and the consumption of jet energy, and the material washed up by the air begins to land at different heights according to its gravity.

2.Convection zone: Located in the upper part of the air punch area, due to the slowdown of the gas rush of the eruption column, the gas in the gas column is scattered outward, and the gas in the atmosphere is continuously added, forming the convection of the gas inside and outside the eruption column, so it is called the convection zone.

The dense material in this area begins to fall. Substances that are less dense than the atmosphere continue to rise by the buoyancy of the atmosphere. The height of the air column in the convection zone is larger, accounting for about seven-tenths of the total height of the eruption column.

3.Diffusion Zone: Located at the very top of the eruption column, the eruption column is in a state where the pressure of the eruption column and the atmosphere above the air is basically equilibrated. The eruption column is constantly rising, and the gas and low-density substances in the column are diffused in the horizontal direction, so it is called the diffusion zone.

Volcanic ash that is carried into the air can form ash clouds, which can drift in the air for long periods of time, which can have a great impact on the regional climate and even cause disasters. The height of the cylinder in this area accounts for about two-tenths of the total height of the column.

The collapse of the eruption column.

During the ascent process, the eruption column carried debris of different particle size and density, which collapsed at different heights and at different stages according to the gravity.

The technical term for a volcanic eruption is a form of crustal movement, in which heat energy accumulates from the crust.

After a certain point, it will be released outward, and the released energy will erupt from some active volcanoes. However, it usually does not erupt for no reason, but after a certain amount of pressure, it will erupt from the surface of the weak hair. It is usually the pressure caused by the movement of the earth's crust.

There are three main types of volcanoes, namely active volcanoes, extinct volcanoes, and dormant volcanoes. Generally, volcanoes that erupt are active volcanoes, and extinct volcanoes are almost impossible to erupt. As far as our country is concerned, there are many extinct volcanoes in our country, but there is almost no possibility of eruptions.

Dormant volcanoes are different, they only enter a dormant state temporarily, and if they wake up at a certain time, they will erupt. Dormant volcanoes actually.

It's just that an active volcano has gone into a dormant state.

Many people may not have encountered volcanoes, so they feel that volcanoes are not as harmful as **, but once the real volcano erupts, it is much more terrifying than **, you must know that many of the extinction of dinosaurs in the past was caused by volcanic eruptions, so once a large volcano erupts, human beings may become extinct.

But at present, the current volcano will not erupt en masse like then, so humans can still be on fire for some years. So, how terrifying are volcanic eruptions? A normal fire can burn down a house and trees, let alone magma from a volcanic eruption.

Maybe you've seen magma from a lot of ****, isn't it the same as the iron slurry in the iron-burning furnace? As soon as that one is poured down, everything will die or be reduced to ashes. In particular, the nearby villages are likely to be submerged and burned.

In addition to this devastating hazard, the smoke and gases emitted when it erupts can affect the global climate. These gases merge into cumulonus clouds and form rainfall, which can also lead to storms.

Of course, there are pros and cons to everything, and sometimes volcanic eruptions can bring us certain benefits. After a volcanic eruption, the soil becomes more fertile and the plants regrow and grow more of high quality. A lot of mineral resources will also be formed.

So, how do we escape in the face of a volcanic eruption? First of all, you know the precursors of volcanic eruptions: there will be noticeable on the surface.

Some underground outlets will have peculiar smells, such as vents, springs, etc.: some animals and plants will die abnormally; The water level and temperature will be different.

Often, etc. If you notice this kind of phenomenon, you should evacuate the area as soon as possible, and you can choose the fastest means of transportation to leave, and you need to protect your head with something in the process.

There are two types of volcanic eruptions: fissure eruptions, meso-eruptions (linear eruptions), and central eruptions.

1. Fractured eruption (linear eruption).

A fissured eruption is when magma overflows to the surface along a huge fissure in the lithosphere. It is dominated by mafic lava and has no ** phenomenon. Lava flows out in a faceted pattern. Typical representatives: Laki Volcano in Iceland Talawela Volcano in New Zealand.

2. Central eruption

Magma gushes up along tubular volcanic channels and overflows from the crater. According to the intensity of the eruption, it is divided into: quiet (Hawaiian), violent (Peiret), and progressive characteristics are in between.

Causes of volcanic eruptions:

Volcanoes erupt because magma erupts along weak links in the earth's surface under certain geological action. The Earth's surface is made up of plates, and the edges of the plates are the weak link, especially when one plate subducts below another.

Its subduction zone is easy to cause convection and melting of materials in the earth's interior, producing magma, which is more likely to lead to mountain eruptions. The Pacific Rim is the edge of the tectonic plate and the subduction zone, where more than 2 3 volcanoes are distributed around the world, so it is called the "chain of fire" on the earth.

There are also some volcanoes in the plate, which are often found in continental rift systems, such as the East African Rift Valley, the East Asian Continental Rift System, and the Rhine Graben. There are also hot spots or mantle plumes within the plates, like pus boils on the earth, where magma erupts from the surface to form volcanoes.