There is a "liquid zone" between 100 and 150 km under the crust. In this liquid zone, there is a molten silicate substance containing gas volatiles at high temperature and high pressure, that is, magma. Once it rushes out from the weak part of the earth's crust, a volcano is formed. Volcanic eruptions can spew out all kinds of substances. Volcano is the window of the blazing center of the earth and the most explosive force on the earth. [ 1]

Volcano is formed by high-temperature magma ejected from the earth's crust and its related gases and debris in the deep underground, and has a special geological structure. Volcanic eruption is a very serious natural disaster, often accompanied by earthquakes. Volcanoes can be divided into dead volcanoes and active volcanoes. An active volcano that has not erupted for a period of time is called a dormant volcano. There is also a mud volcano, which is not a volcano strictly in science, but many people also regard it as a type of volcano. Volcanic eruption will do harm to human beings, but it also brings many benefits. Many gems are formed by volcanic eruptions; Volcanic eruption can also expand the land area, and the Hawaiian islands are formed by volcanic eruption; Some volcanoes can also be turned into scenic spots to promote tourism, such as Mount Fuji in Japan. The discipline that specializes in volcanic activity is called volcanology.