volcano

• Summit:

  • The highest point or apex of the volcano
  • At the summit, there is an opening called a vent
  • Sides or flanks of a volcano that radial from the main or central vent
• Slopes: The sides of the volcano
• Base: The lower outer part of the volcano
• Magma chamber:

  • Region beneath the vent of a volcano where molten rock or magma is deposited or stored before eruption
• Main Vent:

  • The main opening or outlet on the surface of a volcano that emits lava, gases, ash, and other volcanic materials
• Conduit:

  • Underground central tube-like or pipe-like structure of a volcano that connects the magma chamber to the crater
• Side vent: A smaller outlet through which magma escapes from the volcano
• Crater:

  • The mouth of the volcano which is a funnel-shaped or bowl-shaped hollow at the top of the vent from where magma, ash, and gas come out
• Lava: Molten rock which is given off onto the surface of the Earth when a volcano erupts
• Ash and Gas Cloud: Mixtures of rock, minerals, glass particles, and gases expelled or pushed out of the volcano during a volcanic eruption
• Phreatic eruptions are caused by water vaporizing as it comes into contact with hot rocks or lava.
• The magma chamber is the location where molten rock accumulates.
• Volcanic hazards include lahars (mudflows), pyroclastic flows (hot clouds of ash and gas), landslides, tsunamis, and toxic gases such as sulfur dioxide.
• Pyroclastic flow: A fast moving cloud of superheated ash, dust, and rock fragments that can travel at speeds up to 700 mph.
• Magmatic eruptions occur when there is an increase in pressure within the magma chamber due to the buildup of gas bubbles.
• Explosive eruptions can be triggered by the sudden release of built-up pressure in the magma chamber.
• 
  

  • Hawaiian: Effusive, low viscosity, lava plume less than 100 meters
  • Strombolian: gentle explosive burst, relatively high viscosity, lava plume between 100 meters to 1000 meters
  • Vulcanian: explosive, high viscosity, few lava, mostly plume, volcanic bombs, lava plume between 1000 meters to 5000 meters
  • Pelean: severely explosive outburst, pyroclastic flows, plumes, ash, rocks, pumice, lava plume between 5000 meters to 19000 meters
  • Plinian: cataclysmic strongly explosive, high viscosity, low amounts of lava, plume, rocks, eruption height between 5000 meters to 10,000 meters
• Types of volcanic eruptions based on explosiveness:

  • Vulcanian: explosive, high viscosity
  • Pelean: severely explosive outburst
  • Plinian: cataclysmic strongly explosive
• Types of volcanic eruptions based on eruption height:

  • Lava plume less than 100 meters: Effusive
  • Lava plume between 100 meters to 1000 meters: Strombolian
  • Lava plume between 1000 meters to 5000 meters: Vulcanian
  • Lava plume between 5000 meters to 19000 meters: Pelean
  • Eruption height between 5000 meters to 10,000 meters: Plinian
• Phreatic volcanic eruptions involve hydrothermal steam blasts without magma involvement, with eruption heights between 16 km to 25 km
• Magma is extremely hot molten rocks located under the Earth's surface
• Magma consists of rocks that have melted totally or partially and can form into "igneous rocks" containing silicate elements when cooled
• Common elements found in magma include Magnesium, Silicon, Potassium, Aluminum, and others
• The composition of gases in magma includes water vapor, carbon dioxide, and minor amounts of sulfur, chlorine, and fluorine gases
• Factors affecting the viscosity of magma:

  • Silica content (Si)
  • Dissolved water (H2O)
  • Temperature
• Classification of magma:

  Basaltic:

  • Low viscosity
  • Temperature: 1000°C to 1200°C
  • 1-2% gas content
  • Least explosive
  • 50% silica content

  Andesitic:

  • Intermediate viscosity
  • Temperature: 900°C to 1000°C
  • 3.4% gas content
  • 60% silica content
  • Intermediate explosiveness

  Rhyolitic:

  • High viscosity
  • Temperature: 750°C to 900°C
  • 4-6% gas content
  • 70% silica content
  • Most explosive
• Extrusion: When lava cools outside the Earth

  Intrusion: When magma cools within the Earth
• Lahar: A mudflow formed from volcanic debris mixed with rainwater.
• Pyroclastic flow: Hot ash and rock fragments that move downhill at high speeds during an eruption.