Science lesson 1 (4TH QUARTER) (9TH)

• Pressure


  Builds deep in the earth where the magma is
• Volcanic eruption


  Gases escape and violently explode
• Pressure during volcanic eruptions

  Comes from the gases
• Types of Volcanoes


  • Shield
  • Cinder
  • Composite
  • Hawaiian
  • Strombolian
  • Plinian
  • Phreatic
  • Vulcanian
• Active Volcanoes


  • Have erupted at least once within the last 10,000 years
• Inactive/Dormant Volcanoes


  • Have not erupted in the past 10,000 years but still have a possibility to erupt
• Effusive Eruptions


  Characterized by outpourings of lava on to the ground
• Shield Cone Volcanoes


  • Wide and somewhat flat
  • Form from a quiet eruption
  • Lava flows out quietly and for great distances
  • Low silica level
  • Low viscosity lava
  • High or low levels of gas
• Composite Volcanoes (Strato Volcanoes)

  • Magma is rich in silica and much thicker than magma from a shield volcano
  • Gases get trapped inside this thicker magma
  • Form from explosive eruptions
  • Produce a lot of lava and ash
  • Small, with steep sides
  • High in silica
  • High viscosity magma
  • High levels of gas
• Cinder Cone Volcanoes (Scoria Cones)


  • Magma has large amounts of gas trapped in it
  • Violent and explosive type of eruptions (single type of eruption)
  • Has tall, very steep sides
  • Low silica lava
  • High levels of gas
  • Simplest type of volcanoes
• Volcanic Eruptions


  • Magmatic
  • Phreatic
  • Phreatomagmatic
• Magmatic Eruptions

  • Produce juvenile clasts during explosive decompression of gas within magma that propels it forward
  • Strombolian
  • Hawaiian
  • Vulcanian
  • Pelean
  • Plinian
• Strombolian Eruptions


  • Calmest of the eruption type
  • Lava is very hot, thin, and runny which allows for fast flowing lava flows
  • Fluid basaltic lava is thrown into the air in jets from a vent or line of vent
• Vulcanian Eruptions


  • An eruption resulting from the release of large quantities of accumulated magmatic gas which lifts fine ash with great force high into the air
  • More violent and explosive than Strombolian eruptions, short, violent, relatively small explosion of viscous magma
• Plinian Eruptions


  • The largest and most violent of all the types of volcanic eruptions
  • The eruption columns are usually shaped like a mushroom (similar to a nuclear explosion) or an Italian pine tree
  • Characterized by a very high ash cloud that rise upwards to 50,000 feet (almost 10 miles) high
• Plinian Eruption


  • Mount Vesuvius, which erupted in 79 A.D. in Italy
• Pelean Eruptions

  • Eruptions that occur when gas rich pasty lava accumulates to form a dome on volcano
  • "Glowing clouds" of gas and ash flew down the mountain at over 70 miles per hour
  • Occurs when a large quantity of gas, dust, ash and lava fragments are blown out of volcanoes crater
• Phreatomagmatic Eruption


  Characterized by an explosive water magma interaction through which large amount of steams and magmatic gases are released
• Phreatic Eruptions


  • Also called steam blast eruptions
  • Driven by explosive expanding of steam resulting from cold ground or surface water coming into contact with hot rock or magma
• Surtseyan Eruption


  • Kind of hydromagmatic eruption where magma interact explosively with shallow groundwater or surface water
  • Occur when undersea volcano matured enough to break the surface of the water
• Submarine Eruption


  • Type of volcanic eruption that takes place beneath the surface of water
  • They generate at subduction zone and within the tectonic plate where hotspots can be located
  • Pillow lava are ejected
• Subglacial Eruption


  • Interaction between lava and ice often under glacier
  • Occurs at areas of high latitude and high altitude
• Vulcanian Volcanoes


  Characterized by violent and explosive eruptions. Lava flows are fast-moving, intense, and short-lived. Typically produce lava with high silica content and higher viscosity. Also known as Strombolian Volcanoes or Fire Fountaining.
• Shield Cone Volcanoes


  Characterized by a gently sloping, flat-topped shape, resembling a shield. Formed from quiet eruptions with little to no explosive activity. Lava flows are calm, slow-moving, and can travel long distances. Typically produce lava with low silica content and low viscosity.
• Phreatic Eruption


  A steam-powered eruption, occurring when water interacts with hot rocks, without direct magma involvement.
• Lava Flow


  The flow of molten rock (lava) onto the surface, often from a vent or fissure.
• Phreatomagmatic Eruption


  Interaction between magma and water, producing explosive eruptions with a mix of pyroclastic flows and rock.
• Magmatic Eruption

  The eruption of magma (molten rock) from the Earth's interior, producing various types of eruptions.
• Vulcanian Eruptions


  Eruptions resulting from the release of large quantities of accumulated magmatic gas which lifts fine ash with great force high into the air. More violent and explosive than Strombolian eruptions, with viscous magma.
• What's the difference?


  Vulcanian Eruptions: more violent, explosive, and involve viscous magma, while Strombolian Eruptions are less violent, involve less viscous magma.