The cause of the volcanic eruption. The situation inside the earth is very complicated, and the temperature and density inside the earth are also uneven. Under the long-term action, mantle convection will form inside the mantle. With the rise of high-temperature materials in the earth, the pressure of high-temperature materials will decrease and partially melt, thus forming magma sacs. Under the pressure of the stratum, it will break through the crust along the weak place, thus forming a volcanic eruption.
In addition to pressure, the mutual movement between the earth's plates may also lead to volcanic eruptions. When plates collide, the temperature in the collision zone will soar, and the water of some water-bearing minerals will evaporate in large quantities, so the melting point of rocks will decrease. At this time, magma sacs will also appear, which will eventually lead to volcanic eruption.
There are three types of volcanoes: active volcano, extinct volcano and dormant volcano. According to the active degree of volcanoes, we generally divide them into three types. One is an active volcano, which is extremely active and erupts every once in a while. For example, Mount Merapi erupts every three years, which is extremely harmful. An extinct volcano is a volcano that has lost its ability to move. It has a history of eruption before, but it has been silent since then, and it will not erupt magma in the future, which will do little harm to human beings in the future. A dormant volcano is a relatively static volcano, and its state is between an extinct volcano and an active volcano. There was a volcanic eruption before, and then it fell into silence, but it has been in an unstable state, and there is the possibility of magma eruption in the future.
The difference between an extinct volcano and an active volcano. An active volcano is in a semi-active state or periodically erupts magma. The eruption of active volcano is intermittent. Although the time may be different, it is always active. An extinct volcano is completely opposite to an active volcano, and its crater has completely healed. Although many extinct volcanoes have always retained their unique forms, they have been in a very stable state, and there will be no more volcanic eruptions in the future.
There are more than 500 known active volcanoes on the earth. A big volcano can easily destroy a city. Volcanic eruption is very harmful to human beings. Scientists have been trying to stop volcanic eruption by various methods, such as removing magma and cooling the crater with water. The result is to no avail. In the face of such a large-scale natural disaster as volcanic eruption, human beings are extremely small.
With the development of science and technology, although we can't completely stop volcanic eruption, we can predict the time and detect the state of volcanic eruption, and the eruption of active volcanoes is generally periodic. Mount Merapi erupts every three years, so we can take precautions in the future, take precautions in advance, leave enough time to evacuate to a safe place, and try our best to minimize losses.