Types of Volcanoes and Volcanic Eruption

• Consists of fragments of rocks, minerals, and volcanic glass created during volcanic eruptions

  Ash
• A funnel-shaped opening at the top of a volcano

  Crater
• Molten rocks beneath the volcano

  Magma
• Magma that flows out of the earth's surface

  Lava
• Tunnel-like inside a volcano where magma travels to reach the earth's surface

  Main Vent
• Volcano is a vent, hill or mountain from which molten or hot rocks with gaseous material have been ejected. It is also defined as craters, depressions, hills or mountains formed from the ejected materials accumulated on the earth's surface.
• The Philippine Institute of Volcanology and Seismology (PHIVOLCS) have adapted a system by which Philippine volcanoes can be classified as active or inactive.
• An active volcano is a volcano that has a record of eruption within the last 600 years or has erupted 10,000 years ago based on analyses of its materials.
• An inactive volcano is the one that has no record of eruption for the last 10,000 years and its physical form is being changed by agents of weathering and erosion through formation of deep and long gullies.
• There are more than a hundred volcanoes in our country, twenty-four are active, and the others are inactive.
• A volcano has three external parts; a summit, slope and base.
• At the summit, there is an opening which may either be a crater or a caldera.
• A crater is a funnel-shaped opening at the top of a volcano while a caldera is formed when a part of the wall collapses following an explosive eruption.
• A volcano can have one crater, like Mayon Volcano, or more than one, like Taal Volcano that has 47 craters.
• Shield volcanoes are formed from the accumulation of lava that oozes out from the volcano. Since non-viscous lava can flow freely, a broad, slightly domed structure that resembles a warrior's shield is formed. An example of this type is the Mauna Loa Volcano in Hawaii.
• Cinder cones are built from ejected lava fragments. They have steep slope, wide crater and are the most abundant of the three major volcano types. One example of this type is the Paricutin Volcano in Mexico.
• Composite cones or stratovolcanoes are large, nearly perfect sloped structure formed from alternate solidification of both lava and pyroclastic deposits. One perfect example of this type of cone is our Mayon Volcano.
• Shield Cone

  
• Cinder Cone

  
• Composite Cone

  
• Label the parts of the Volcano

  A) Crater

  B) Summit

  C) Slope

  D) Base

  E) Main Vent

  F) Magma

  G) Magma Chamber

  H) Lava