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ABOUT VOLCANO
A volcano is am opening in the earth’s crust through which lava, volcanic ash, and gases escape. Volcanic eruptions are partly driven by pressure from dissolved gas, much as escaping gases force the cork out of a bottle of champagne. Beneath a volcano, liquid magma containing dissolved gases rises through cracks in the Earth’s crust. As the magma rises, pressure decreases, allowing the gases to form bubbles. How the magma (lava) behaves when it reaches the surface depends on both its gas content and chemical composition. Lavas with low silica contents have low viscosities and flow freely, allowing any gas bubbles to escape readily, while lavas with high silica contents are more viscous (resistant to flow), so that any trapped gases cannot escape gradually
FEATURES OF VOLCANO
The main features of a volcano include the magma chamber, vents, craters and slopes. The diagram below shows the main features of a volcano. The magma chamber is a large underground pool of magma. Under pressure, the magma in the chamber can rise up the main vent, which is the central tube through the volcano.
ABOUT VOLCANO
A volcano is am opening in the earth’s crust through which lava, volcanic ash, and gases escape. Volcanic eruptions are partly driven by pressure from dissolved gas, much as escaping gases force the cork out of a bottle of champagne. Beneath a volcano, liquid magma containing dissolved gases rises through cracks in the Earth’s crust. As the magma rises, pressure decreases, allowing the gases to form bubbles. How the magma (lava) behaves when it reaches the surface depends on both its gas content and chemical composition. Lavas with low silica contents have low viscosities and flow freely, allowing any gas bubbles to escape readily, while lavas with high silica contents are more viscous (resistant to flow), so that any trapped gases cannot escape gradually
FEATURES OF VOLCANO
The main features of a volcano include the magma chamber, vents, craters and slopes. The diagram below shows the main features of a volcano. The magma chamber is a large underground pool of magma. Under pressure, the magma in the chamber can rise up the main vent, which is the central tube through the volcano.
