science volcanoes

• Lava


  Red-hot molten rock material violently or quietly emitted by a volcano
• Obsidian


  Dark glassy rock that forms from lava and cools quickly
• Scoria or Pumice


  • Lightweight rocks with holes that are from lava and harden while steam and other gasses are still bubbling from it
• Tuff


  Volcanic ash cemented together and forms into a rock
• Magma Chamber


  Molten rock forms an expanded area of magma
• Viscosity


  Resistance of a liquid material, such as lava, to flow. It is also described as the liquids' thickness and stickiness
• Volcanic Eruption


  Molten rock and materials called magma or lava are emitted in the form of flowing masses such as lava flows, discrete particles such as volcanic ash and pyroclastic steam from a crater
• Volcano - Is a mountain, hill, or vent formed around a crack in the Earth’s crust, where tectonic plates have pulled apart, through which molten rock and other hot materials exude. 
• Magma - When tectonic plates move apart, the rock becomes liquid or molten rock. 
• Vent - An initial opening at the top of the volcano’s crater. 
• Caldera - A crater is usually narrow, but sometimes it blows apart or collapses, forming a wide basin-like hollow. 
• Types of Volcanoes


  • Active Volcanoes
  • Inactive Volcanoes
  • Extinct Volcanoes
• Active Volcanoes


  Is one erupting or had recently erupted and has a record of eruption within the span of 600 years, or those which erupted within the last 10,000 years
• Inactive Volcanoes


  Also known as dormant or sleeping volcanoes, Is one that could erupt but has not erupted for more than 10,000 years. It shows signs of underground activity, their physical form is being changed by agents of weathering and soil erosion through the development of long and deep gullies
• Extinct Volcanoes


  Is one which is no longer active and hasn't erupted in historical times
• Shield Volcanoes


  • Have a broad base and gently sloping sides
  • Layers of lava flow out from the vent
  • Lava hardens and slowly builds up to form the cone
• Shield Volcanoes


  • Mauna Loa and Kilauea in Hawaii
• Cinder Cones


  • Also known as scoria cones
  • Built from ashes and pieces of lava hardened by the air around the vent
  • Form a steep volcano with a wider crater
• Cinder Cones


  • Mojave Volcano in California, USA
  • Cerro Negro in Nicaragua
  • Parikutin Volcano in Mexico
• Composite Cones or Stratovolcanoes

  • Have large, nearly perfect slope structures
  • Formed from alternating layers of hardened lava flows and pyroclastic materials
• 1. Vulcanian Eruption - Thick and viscous magma flows, surrounding the vent as solid lava and dust are emitted. 
• 1. Strombolian Eruption - Is violent with continuous ejection of magma and gas. This resulted in the formation of volcanic bombs and cinder cones. 
• 1. Phreatomagmatic Eruption - Is a violent eruption wherein the magma and the water are in contact. The result is the formation of a large column of a very fine ash at high speed with sideways emission of pyroclastics called “base surges". 
• 1. Phreatic or Hydrothermal Eruption - Hot rocks surrounded by water results in short-lived stream driven eruptions with ash falls.