Volcano Types and Formation

Types of Volcanoes

• Volcanoes are natural openings in the Earth's surface.
• Molten rocks, smoke, gases, and ashes are ejected from volcanoes.
• A crater is a funnel-shaped depression at the top of a volcano.
• It is formed as a result of explosive eruption.
• A caldera is a volcanic crater that is formed when a part of the crater collapses after an explosive eruption.
• Magma is hot fluid or semi-fluid material below the Earth's crust, usually made of molten rocks inside the earth.
• Lava is magma that is ejected out of a volcano.
• The Latin word "lava" means "to slide."

Types of Volcanoes According to Shape

• Volcano shapes vary, with three main types.
• Shield Volcanoes are formed by the accumulation of lava that oozes out from the volcano.
• Non-viscous lava flows freely, creating a broad, slightly domed structure resembling a warrior's shield.
• Mauna Loa in Hawaii is an example.
• Cinder Cone Volcanoes are built from ejected lava fragments.
• They have steep slopes, wide craters, and are the most abundant of the three major volcano types.
• Mt. Paricutin in Mexico is an example.
• Composite Volcanoes are also known as "stratovolcanoes."
• They are large, nearly perfect sloped structures formed from the alternate solidification of both lava and pyroclastic deposits.
• Mt. Mayon in the Philippines and Mt. Fuji in Japan are examples.

Types of Eruption

• Volcano eruptions have different causes.
• Phreatic/Hydrothermal eruptions are steam-driven, occurring when hot rocks come into contact with water.
• Phreatomagmatic eruptions are violent, resulting from contact between water and magma.