Causes of Volcanic Eruptions
Volcanoes occur in specific regions due to a significant increase in temperature of certain materials deep within the Earth’s crust, leading to their melting. This molten material found beneath the surface is known as magma. When magma rises to the Earth’s surface, it forms a flowing liquid referred to as lava. Additionally, this molten material can contain various gases and other impurities. The ascent of magma to the surface is primarily driven by tectonic plate movements; when these plates move apart, the molten liquid fills the gap created by their separation. Alternatively, magma can also escape when tectonic plates push against each other, resulting in one plate sliding beneath another. The intense pressure and heat within the Earth cause the subducting plate to melt, eventually emerging as volcanic lava.
Types of Volcanoes
The following are the primary types of volcanoes found worldwide:
- Shield Volcanoes: These are characterized by their broad, gently sloping sides and form when lava flows freely through vents, accumulating around the opening to create a shield-like appearance.
- Composite Volcanoes: Many mountains globally, such as Mount Cotopaxi and Mount Rainier, exemplify this type. Composite volcanoes have numerous vents and fissures from which magma erupts, posing significant risks when they erupt.
- Dome Volcanoes: These volcanoes resemble large, rounded shields from above. The magma that erupts from dome volcanoes is often highly viscous and can cause accumulations that rise over time.
- Volcanic Domes: This type of volcano can erupt violently, with the molten material displaying high viscosity, often leading to explosive eruptions.
Negative Impacts of Volcanoes
Volcanoes can pose substantial risks to the environment, resulting in mudslides, forest fires, water contamination, and other hazardous phenomena. The eruptions are associated with adverse health effects in humans, such as respiratory issues, burns, and conditions like asthma and emphysema. These health risks stem from exposure to high levels of harmful gases, including carbon dioxide.