Tips on volcanoes

1. Knowledge about volcanoes

Overview of volcanoes: There is a "liquid zone" 100 to 150 kilometers below the earth's crust, where gases volatilize under high temperature and pressure. parts of molten silicate material, that is, magma.

Once it breaks out of the surface from a weak spot in the earth's crust, it forms a volcano. There are about 2,000 known "extinct volcanoes" on the earth; there are 51,638 "active volcanoes" that have been discovered, including 516,154 on land and 5,464 undersea volcanoes.

Volcanoes are unevenly distributed on the earth. They all appear in fault zones in the earth's crust. Globally, volcanoes are mainly concentrated in the Pacific Rim and Indonesia north through Myanmar, the Himalayas, Central Asia and the Mediterranean. Ninety-nine percent of the active volcanoes on the earth today are distributed in these two belts.

The history of volcanoes is very long. Some volcanoes have erupted before human history, but are no longer active. Such volcanoes are called "extinct volcanoes"; however, there are also "extinct volcanoes" that will suddenly erupt due to changes in the earth's crust, which are called "dormant volcanoes". "Volcano"; throughout the history of mankind, volcanoes that have erupted from time to time are called "active volcanoes".

Volcanic activity can eject a variety of materials. Among the solid materials ejected, there are usually rock fragments, debris and volcanic ash that have been broken by explosions. Among the liquid materials ejected, there are usually lava. Flows, water, various aqueous solutions, and mudflows mixed with water, debris and volcanic ash, etc.; among the ejected gaseous substances, there are generally water vapor and oxides of carbon, hydrogen, nitrogen, fluorine, sulfur, etc. In addition, during volcanic activities, visible or invisible light, electricity, magnetism, sound and radioactive substances are often ejected. These substances can sometimes kill people, or cause electricity, instruments, etc. to malfunction, causing airplanes to malfunction. , ships, etc. crashed.

The strength of a volcanic eruption is related to the properties of the lava, and the eruption time can range from a few hours to thousands of years. Volcanoes can be divided into three categories according to volcanic activity: active volcanoes, extinct volcanoes and dormant volcanoes.

Among them, dormant volcanoes refer to eruptions that have been recorded in human history, but no activity has been seen since. There are about 500 active volcanoes in the world. Volcanic eruptions can cause huge losses to humans, lives and property in a short period of time. It is a catastrophic natural phenomenon.

However, after a volcano erupts, it can provide abundant land, thermal energy and many mineral resources, as well as tourism resources. Volcanic eruptions are described in detail in many books.

For example, "Heilongjiang Gaiden" records the eruption of two volcanoes in the Wudalianchi volcano group in Heilongjiang. "In the southeast of Mergen (now Nenjiang), one day fire broke out in the ground, stones flew up, and the sound shook the fields. After a few days, the fire died out, and the land turned into a swamp. This happened in the fifty-eighth year of Kangxi's reign."

Volcano types (1) Classification based on volcanic activity 1. Active volcano (active volcano) refers to volcanoes that are still active or have periodic eruptions in modern times. This type of volcano is in a period of peak activity.

For example, the Melapi volcano on Jutu Island has been erupting for a period of time every two or two years on average since this century. The recent volcanic activity in my country is the Qixing Mountain, the main peak of the Datun volcanic group on Taiwan Island. famous. On the mainland, there has only been a volcanic eruption record in the Cardassie volcano group in Yutian in the western section of the Kunlun Mountains in Xinjiang in 6 years.

The eruption created a flat-topped volcanic cone. 2. An extinct volcano refers to a volcano that has erupted in prehistoric times but has not been active in history.

Such volcanoes have lost their ability to move. Some volcanoes still maintain their complete volcanic form, while others have been weathered and eroded, leaving only incomplete volcanic remains. The Datong volcano group in Shanxi, my country, has 99 isolated volcanoes distributed within an area of ??about 123 square kilometers. Among them, the Langwoshan volcano cone is nearly 1,900 meters high.

3. Dormant volcano refers to a volcano that has erupted in history but has been relatively static for a long time.

Such volcanoes all have well-preserved volcanic shapes and are still capable of volcanic activity, or it cannot be concluded that they have lost their volcanic activity.

For example, my country's Baektu Mountain Tianchi erupted twice in 1327 and 1658, and there were many activities before that. Although there is currently no eruptive activity, high-temperature gases are continuously ejected from some unfathomable fumaroles on the hillside, indicating that the volcano is currently dormant.

It should be noted that there are no strict boundaries between these three types of volcanoes. Dormant volcanoes can be resurrected, and extinct volcanoes can also be "resurrected".

In the past, it was always believed that Mount Vesuvius in Italy was an extinct volcano. At the foot of the volcano, people built many towns and opened vineyards on the slopes of the volcano. However, in 79 AD, Mount Vesuvius Suddenly, the high-temperature volcanic eruption attacked the unsuspecting ancient cities of Pompeii and Heragonum, destroying and killing both cities and their residents. (2) Eruption types classified according to volcanic eruption conditions Volcanism is affected by factors such as the nature of magma, the pressure in the underground magma chamber, the shape of the volcanic channel, and the volcanic eruption environment (on land or underwater), resulting in the following types of volcanic eruptions.

1. Fissure eruption Magma overflows to the surface along huge cracks in the earth's crust, which is called a fissure eruption. This type of eruption does not have a strong explosive phenomenon. The ejected material is mostly alkaline magma, which often forms a lava platform covering a wide area after condensation.

For example, the Permian Emeishan basalt distributed in the junction area of ??Sichuan, Yunnan and Guizhou provinces in southwest my country and the Tertiary Hannuoba basalt north of Zhangjiakou, Hebei are both fissure-type eruptions. Modern fissure-type eruptions are mainly distributed at mid-ocean ridges on the ocean floor. Only Iceland can see such volcanic eruptions on the continent, so they are also called Icelandic volcanoes.

2. Central eruption: Underground magma erupts to the surface through tubular volcanic channels, which is called a central eruption. This is the main form of modern volcanic activity, which can be subdivided into three types: Quiet type: When a volcano erupts, only a large amount of hot lava quietly overflows from the crater and flows slowly along the hillside, like boiled rice soup flowing from a rice pot. It's like boiling and diarrhea.

The overflowing material is mainly alkaline magma, which has a high temperature, low viscosity and is easy to flow. It contains less gas and has no explosion phenomenon. It is represented by Hawaiian volcanoes and is also called the Hawaiian type.

Explosive type: When a volcano erupts, a violent explosion occurs, and a large amount of gas and pyroclastic material are ejected at the same time. The magma ejected is mainly medium-acidic magma. The eruption of Mount Pelé in the West Indies on June 25, 1568 was of this type, also known as the Pelé type.

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2. Basic knowledge and pictures about volcanoes

Overview of volcanoes

There is a "liquid zone" 100 to 150 kilometers below the earth's crust "There is molten silicate material containing gas volatiles under high temperature and high pressure, that is, magma. Once it breaks out of a weak spot in the earth's crust, it forms a volcano.

There are about 2,000 known "extinct volcanoes" on the earth; there are 51,638 "active volcanoes" that have been discovered, including 516,154 on land and 5,464 undersea volcanoes. Volcanoes are unevenly distributed on Earth and occur along fault lines in the Earth's crust. Globally, volcanoes are mainly concentrated in the Pacific Rim and Indonesia north through Myanmar, the Himalayas, Central Asia and the Mediterranean. Ninety-nine percent of the active volcanoes on the earth today are distributed in these two belts.

The history of volcanoes is very long. Some volcanoes have erupted before human history, but are no longer active. Such volcanoes are called "extinct volcanoes"; however, there are also "extinct volcanoes" that will suddenly erupt due to changes in the earth's crust, which are called "dormant volcanoes". "Volcano"; throughout the history of mankind, volcanoes that have erupted from time to time are called "active volcanoes".

Volcanic activity can eject a variety of materials. Among the solid materials ejected, there are usually rock fragments, debris and volcanic ash that have been broken by explosions. Among the liquid materials ejected, there are usually lava. Flows, water, various aqueous solutions, and mudflows mixed with water, debris and volcanic ash, etc.; among the ejected gaseous substances, there are generally water vapor and oxides of carbon, hydrogen, nitrogen, fluorine, sulfur, etc. In addition, during volcanic activities, visible or invisible light, electricity, magnetism, sound and radioactive substances are often ejected. These substances can sometimes kill people, or cause electricity, instruments, etc. to malfunction, causing airplanes to malfunction. , ships, etc. crashed.

The strength of a volcanic eruption is related to the properties of the lava, and the eruption time can range from a few hours to thousands of years. Volcanoes can be divided into three categories according to volcanic activity: active volcanoes, extinct volcanoes and dormant volcanoes. Among them, dormant volcanoes refer to eruptions that have been recorded in human history, but no activity has been seen since. There are about 500 active volcanoes in the world.

Volcanic eruptions can cause huge losses to humans, lives and property in a short period of time. It is a catastrophic natural phenomenon. However, after a volcano erupts, it can provide abundant land, thermal energy and many mineral resources, as well as tourism resources.

Many books have detailed descriptions of volcanic eruptions. For example, "Heilongjiang Gaiden" records the eruption of two volcanoes in the Wudalianchi volcano group in Heilongjiang. "In the southeast of Mergen (now Nenjiang), one day fire broke out in the ground, stones flew up, and the sound shook the fields. After a few days, the fire died out, and the land turned into a swamp. This happened in the fifty-eighth year of Kangxi's reign."

Types of volcanoes

(1) Classification according to volcanic activity

1. Active volcano (active volcano)

Refers to modern activities that are still active or occur periodically Eruptive active volcano. This type of volcano is in a period of peak activity. For example, the Melapi volcano on Joutu Island has been erupting continuously for an average of two to two years since this century. The most famous volcanic activity in my country in recent times is Qixing Mountain, the main peak of the Datun volcano group on Taiwan Island. On the mainland, there has only been a volcanic eruption record in the Cardassie volcano group in Yutian in the western section of the Kunlun Mountains in Xinjiang in 6 years. The volcanic eruption formed a flat-topped volcanic cone with an altitude of 1,000,041 meters at the top of the cone, a height of 257,461 meters, a diameter of 656,655 meters at the base of the cone, a diameter of 254,688,524 meters at the top of the cone, and a crater depth of 9,659,885 meters.

2. Extinct volcano

Refers to a volcano that has erupted in prehistory but has not been active in history. Such volcanoes have lost their ability to move. Some volcanoes still maintain their complete volcanic form, while others have been weathered and eroded, leaving only incomplete volcanic remains. The Datong volcano group in Shanxi, my country, has 99 isolated volcanoes distributed within an area of ??about 1,230 square kilometers. Among them, the Langwoshan volcano cone is nearly 19,000 meters high.

3. Dormant volcano

Refers to a volcano that has erupted in history but has been relatively static for a long time. Such volcanoes all have well-preserved volcanic shapes and are still capable of volcanic activity, or it cannot be concluded that they have lost their volcanic activity. For example, my country's Baektu Mountain Tianchi erupted twice in 1327 and 1658, and there were many activities before that. Although there is currently no eruptive activity, high-temperature gases are continuously ejected from some unfathomable fumaroles on the hillside, indicating that the volcano is currently dormant.

It should be noted that there are no strict boundaries between these three types of volcanoes. Dormant volcanoes can be resurrected, and extinct volcanoes can also be "resurrected". In the past, it was always believed that Mount Vesuvius in Italy was an extinct volcano. At the foot of the volcano, people built many towns and opened vineyards on the slopes of the volcano. However, in AD 26, Mount Vesuvius suddenly erupted, causing a high-temperature volcanic eruption. The attack took over the two ancient cities of Pompeii and Hiragunum, which were defenseless. Both cities and their residents were completely destroyed and killed.

9. A 500-word explanatory essay on computer common sense

Knowledge of volcanoes_A 500-word explanatory essay about volcanoes

Author: His fifteenth uncle Time: 2018 -08-13 11:22:15 Collection

Volcano is a word that everyone is familiar with and cannot be more familiar with. But, how much do you know about volcanoes? Ahem (clears throat), let me tell you a little knowledge about volcanoes!

Volcanoes are divided into extinct volcanoes, active volcanoes and dormant volcanoes. Extinct volcanoes are volcanoes that are no longer erupting. Active volcanoes refer to those volcanoes that still erupt. Dormant volcanoes refer to those volcanoes that are "sleeping", that is, volcanoes that can still erupt. Now scientists have discovered that there are already 3,500 volcanoes on the earth!

What should I do if a volcano erupts? Don't worry, don't worry, I'll teach you some ways to escape. When a volcano erupts, wear a helmet or mask to avoid inhaling the toxic smoke and gas produced during the eruption. What should I do if the lava flows over? Run away quickly, run up the mountain, and try to escape from the magma flow as quickly as possible. The most terrifying thing is the lahar, in which many people were killed. By the way, people in the city of Aromel died from volcanic mudflows. Volcanic mudflows have strong viscosity, high temperature, and strong mobility. They are more powerful than mudslides and landslides! Escape quickly and try to get to the top of a mountain higher than the lahar.

How do volcanoes erupt? Due to the movement of the earth's crust, the rocks in the rock layer move with the magma. When there is squeezing pressure, magma pours out of the crater, forming a volcanic eruption.

Are you satisfied with today’s volcano knowledge? Next time, dust - the "tramp of nature" will never leave!