Changes Due to Volcanic Eruptions

• Volcano


  An opening in the Earth's crust where molten rocks, ashes, and gaseous materials are forced out
• Crater


  The opening of a volcano
• Volcanoes


  • Vary in sizes - some are low-lying depressions, others are tall
  • Vary in shape - some are cone-shaped, others are dome-shaped
• Volcanic eruption


  1. Tectonic plates collide

  2. Massive rocks underground deform

  3. Temperature and pressure build up

  4. Rocks melt, producing magma
• Magma chamber


  Inside the volcano, where molten rock is forcefully driven out by intense heat and pressure
• Eruption


  The release of magma from the crater
• Lava


  The magma that flows out on the surface
• Volcanic eruption


  • Can be explosive or nonexplosive
  • Explosive eruption - large amounts of pyroclastic materials ejected into the air
  • Nonexplosive eruption - lava just flows out of the crater and gaps along the sides
• Explosive eruption


  Gases in the magma are trapped, causing a build-up of pressure in the magma chamber, resulting in a violent explosion
• Nonexplosive eruption


  Less pressure in the magma chamber, as magma is located nearer the Earth's surface
• Volcanic eruptions can cause damage to plants, animals, people, and property
• Volcanic eruptions can also have beneficial effects in nature
• Lava flow can burn anything in its path
• Mudflow or lahar can cause landslides, flooding, and damage to buildings and farms
• Volcanic ash and dust can irritate the lungs and cause health problems
• Strong eruptions can trigger earthquakes
• Pyroclastic materials


  Lava, ashes, volcanic glass, and rocks ejected by a volcanic eruption
• Pyroclastic materials can make the soil fertile
• Fumaroles


  Holes or vents where gases come out from the volcano, providing geothermal steam to generate electricity
• Industrial materials produced by volcanic eruptions

  • Pumice
  • Sulfur
• Rocks from volcanoes help scientists study the interior of the Earth