Volcano Terminology and Types

Defining Volcano Terminology

• A volcano is an opening in the Earth's surface where molten rock, smoke, gases, and ash are ejected.
• Mayon Volcano in the Philippines is an active volcano and notable for its perfect cone shape.
• A crater is a funnel-shaped depression at the top of a volcano formed by an explosive eruption.
• A caldera is a large volcanic crater formed when the magma chamber beneath a volcano empties and the surrounding rock collapses.
• Magma is hot, fluid, or semi-fluid material beneath or within the Earth's crust, typically made of molten rock.
• Lava is the molten rock that is ejected from a volcano.

Types of Volcanoes Based on Shape

• Shield volcanoes are broad, slightly domed structures formed by the accumulation of fluid lava flows. They resemble a warrior's shield, hence the name.
  • Example: Mauna Loa in Hawaii
• Cinder cone volcanoes are built from ejected lava fragments. They have steep slopes, wide craters, and are the most common type of volcano. Also known as scoria cones.
  • Example: Mount Parícutin in Mexico
• Composite volcanoes are tall, nearly perfect cone-shaped structures formed by alternating layers of lava and pyroclastic deposits (rock fragments ejected from a volcano). They are also known as stratovolcanoes.
  • Example: Mayon Volcano in the Philippines

Types of Volcanic Eruptions

• Phreatic eruptions are steam-driven explosions caused by the contact of hot rocks with water.
  • Example: Taal Volcano eruption in January 2020.
• Phreatomagmatic eruptions are violent eruptions caused by the interaction of water and magma.
• Strombolian eruptions are characterized by periodic, weak to violent eruptions with fountaining lava.
• Vulcanian eruptions are characterized by tall, explosive eruptions reaching up to 20 kilometers high, with pyroclastic flows and ash.
• Plinian eruptions are the most explosive type of eruption, with large amounts of gas and pyroclastic materials.
  • Example: Mount Pinatubo eruption in 1991.

Volcano Activity Classification

• Active Volcanoes have a record of eruption.
• Inactive Volcanoes show no activity and have no record of eruption.
  • Example: Mount Kanlaon in Negros Occidental, Philippines.

Importance of Volcanoes

• Volcanoes have a significant role in sustaining life on Earth.
• They release heat and gases that contribute to the Earth's atmosphere and help regulate climate.
• Volcanic activity also creates fertile soil, contributing to agriculture.

Explore the fascinating world of volcanoes with this quiz on essential terminology and types. Learn about different shapes of volcanoes, including shield and cinder cone types, as well as key concepts like craters and magma. Perfect for anyone looking to deepen their understanding of volcanic geology.