Question

What are the main reasons for a volcanic eruption?

Answer 1

Instructions:

• Explain Volcanic Eruption
• Give the main reasons for a volcanic eruption

Solution:
Volcanic Eruption

• A volcano is an opening in the Earth’s crust through which lava, volcanic ash, and gases escape. A volcanic eruption occurs when hot materials from the earth’s interior are thrown out of a volcano. Some volcanic eruptions are explosive, and others are not. The eruption becomes dangerous when the magma is highly viscous, with a large amount of gas and when the vent on the earth’s surface is narrow. But if the magma is less viscous with less amount of gas and where the vent is broad and long, then the molten lava comes out slowly and spreads on the earth’s surface without explosion.

Reason for Volcanic Eruption

1. High temperature in the interior of the earth: As we move down the earth's surface, the temperature starts increasing.
2. Creation of magma: Magma is created beneath the earth's surface as the rocks and other materials meltdown due to the increase in temperature.
3. Creation of gases and vapour: When the water percolates through the cracks formed in the weak surface of the rocks, it gets converted into vapour.
4. Rising of magma towards the earth’s surface: The vapour produced has high pressure and because of the lack of space, it tries to come out with great force, leading to eruption. Thus, the gases present in the magma reach near the surface of the earth and erupt with high pressure in the form of lava, ash, gases and rock pieces of various sizes and shapes.