Volcanoes

• Volcano - is a rupture in the Earth’s (or another celestial body’s) crust that allows hot lava, volcanic ash, and gases to escape from a magma chamber located beneath the surface.
• Volcano - derives from Vulcano
• Volcanoes - the result of the action between the major tectonic plates. 
• Volcanoes - are found where tectonic plates are diverging or converging
• Parts of a Volcano -

  1. Magma Chamber
  2. Vent
  3. Crater
  4. Lava
• Magma Chamber - The pool of magma deep within the Earth
• Vent - The magma flows out through
• Crater - When the magma reaches the top of the volcano during an eruption, a ____is formed
• Crater - opening where magma exits
• Lava -  It is called when the magma is outside the volcano
• Classification of Volcanoes:

  1. Activity
  2. Composition
  3. Structure
  4. Eruption
• by Activity - A volcano may be classified as active, dormant, or extinct based on its life cycle. An active volcano tends to erupt or is already erupting.
• Dormant Volcanoes -  A volcano that is not erupting or is not going to erupt sometime in the near future
• Dormant Volcanoes - are considered active threats even if they have not exhibited any activity for a long time.
• Dormant Volcanoes - "Potentially-active Volcanoes"
• Extinct Volcanoes - have not erupted in the last 30,000 to 40,000 years, and are not expected to erupt anytime soon. 
• By Composition and Structure - They can be shield, cinder, or stratovolcanoes.
• Shield Volcano - is generally low and has a dome shape, like the shield of medieval knights, hence the name.
• Cinder cone - is considered to be the simplest type. These volcanoes are formed from the eruption through a single vent, which results in a bowl-shaped crater at the summit.
• Stratovolcano or Composite Volcano - The most common type. They are called as such because they are formed by alternating layers of lava and pyroclastic materials from multiple eruptions through time.
• By Eruption - Volcanoes can also be classified according to the type of eruption they have exhibited in the past, which is controlled by the chemistry of the magma.
• Explosive eruptions - happen due to the buildup of thick magma with high silica content. It is slow flowing and very viscous. These eruptions are very rapid and very violent. Volcanoes spew lava, ash, and other volcanic material over large distances.
• Quiet or Fissure Eruption - emits a lot of lava coming from a fissure or a crack on the surface.
• Tectonics plates where the Philippines is situated in between:

  1. Philippine Sea Plate
  2. Eurasian Plate
• Arc - A chain of volcanoes