What are Some Different Types of Volcanic Eruptions?

A volcano is a type of accumulating mountain. It is a mountain formed by magma ejection and accumulation inside the crust. Volcano types are divided into active volcano, extinct volcano and dormant volcano. Eruption types are: crack type, center type, and penetration type. Volcanic eruptions are divided into solid, gas, and liquid according to their physical properties.

Volcano type

(1) Classification based on volcanic activity

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Volcanism is affected by magmatic properties, pressure in underground magma reservoirs, volcanic channel shapes, and volcanic eruption environment (onshore or underwater), which make the volcanic eruption of the following types.

1. Fractured eruption

Magma overflows the surface along huge cracks in the crust, called fissure eruption. This type of eruption does not have a strong explosion phenomenon. Most of the effluent is a basic melt. After condensation, it often forms a lava platform with a wide coverage area.

For example, the Permian Emeishan basalt and the Tertiary Hanuoba basalt located north of Zhangjiakou, Hebei, are distributed in the fractured eruption in the southwestern Sichuan, Yunnan, and Guizhou provinces.

Modern fissure-type eruption is mainly distributed on the mid-ocean ridge of the ocean floor. Only Iceland in the mainland can see such volcanic eruption, so it is also called Icelandic volcano.

2.Central eruption

Underground magma erupts from the surface through tubular volcanic channels, known as a central eruption. This is the main form of modern volcanic activity and can be broken down into three types:

Quiet: When a volcano erupts. Only a large amount of hot lava overflowed quietly from the crater, flowing slowly along the hillside, as if the boiled rice soup boiled out of the rice pot.

The overflow is mainly based on the base melt, the melt temperature is high, the viscosity is small, and it is easy to flow. It contains less gas and has no explosion phenomenon. Hawaii volcanoes are its representative, also known as Hawaiian type.

Explosive type: When the volcano erupts, a violent explosion occurs, and a large amount of gas and volcanic debris are ejected at the same time. The ejected melt is mainly medium-acid melt.

On June 25, 1568, the Perey volcanic eruption in the West Indies belongs to this category, also known as the Perey type.

Intermediate type: It is a transitional type between quiet and explosive eruption. This type is dominated by medium-basic lava eruption. If there is an explosion, the explosive force is not great.

It can erupt smoothly for a long period of months, even years, and is characterized by an outbreak with intermission.

It is represented by the Strombod volcano on the Lipari Islands near the west coast of Italy. The volcano erupts approximately every 2-3 minutes, and the flames of the volcano are still visible at 669 kilometers away at night, so it is also called Stromboli.

3. Penetrating eruption

The magma penetrates the earth's crust over a large area and is called a permeation eruption. This is an ancient way of volcanic activity, and no longer exists in modern times. Some scholars believe that in the ancient times, the crust was relatively thin and the underground magma had a large thermal power, which often caused permeable magma ejection activities.