What is a volcano?
A volcano is an opening in the Earth’s surface in which molten rock, dust, gases, and magma escape from beneath the Earth. The conical topography formed by the deposition of these substances released by volcanoes is called volcanic mountain. The name Volcano is named after the Roman god of fire “Vulcan”. The study of volcanoes is called volcanology.
Why and how do volcanoes erupt?
Below the crust in the upper part of the mantle, the rock begins to melt and form magma. In these areas, pressure and temperature are very high, causing rock to melt and form magma. Most magma consists of molten rock, crystalized minerals, and dissolved gases. Magma is less dense than the solid materials from which it forms. As a result, magma pushes higher-density rocks and makes its way upward.
When magma reaches an area where rock layers don’t allow an upward path, it will collect in a large pool that is called a magma chamber. Magma chambers exist deep in the earth’s surface. However some of them exist very close to the surface of earth. Magma chambers are under a great pressure. As pressure increases in the magma chamber, it causes cracks to surround the rock. And eventually, magma finds its way to the surface via a volcanic eruption.
Some volcanoes erupt explosively and some erupt more gently. Several factors affecting these different eruptive styles.
Where do volcanoes occur?
Volcanoes are geologic features that typically occur at the boundaries between separating or colliding lithospheric plates. When the plates break apart, there are opening boundaries that allow magma to flow across the surface and form volcanoes.
When lithospheric plates collide, one plate may go under another. As the plate enters the hot mantle of the earth, it melts which is called magma. Magma eventually rises to the surface and forms volcanoes. These types of volcanoes can be found along the edges of continents, such as the Andes Mountains of South America. Some of the volcanoes such as the islands of Japan rising from the ocean.
types of volcanoes
There are two main two types of volcanoes.
Shield volcanoes are formed by successive eruptions of basaltic magma. These types of volcanoes are capable of flowing great distances down gentle slopes. Hawaii, Samoa, Tahiti, and many other oceanic islands are examples of shield volcanoes.
Stratovolcanoes volcano (composite volcano)
Stratovolcanoes are also called composite volcanoes. Stratovolcanoes are steep conical mountains that consist of layers of alternating lava and ash. Composite volcanoes flow more slowly than shield volcanoes and they cannot spread out very far. Mount Fuji, Mount Rainier, Mount Baker, and Mount Hood are examples of the composite volcanoes.
How Can Scientists Predict Volcanic Eruptions?
It is difficult to predict when and where a volcano will erupt. However, by studying ancient and modern volcanoes, geologists have been able to identify some signs that an eruption may happen. Geologists put volcanoes into three groups based on how active they are.
- Extinct volcanoes have not erupted in recorded history and probably will not erupt again.
- volcanoes are currently not erupting, but they may erupt again.
- Active volcanoes are currently erupting or show signs of erupting in the near future.
What is tephra?
Tephra is the name given to all the material that erupts from a volcano, other than lava. Tephra is also referred to as pyroclastic materials. Ash, block (solid rock), and bomb (molten rock) are the common type of tephra.
Facts about volcanoes
- The biggest volcano in the solar system is Olympus Mons which is on Mars. It is 3 times the height of Mount Everest. It covers an area of 600,000 square kilometres that is almost equal to the size of France.
- there are more than 1500 volcanoes, among them more than 500 volcanoes are active.
- The volcano Mount St. Helens is the most active volcano in the world which is located in America.
- Fuji volcano of Japan is the world’s most beautiful volcano which is a dormant volcano.
- Earth’s largest volcano is the Mauna Loa on the Hawaiian island and is the largest volcano on the planet.