Structure of the earth,Earthquakes,Volcanoes

• Earthquake


  Shaking of the earth's crust caused by sudden movement of plates
• Earthquakes occur


  1. Rock masses move and change in position

  2. Energy stored in rock masses is released

  3. Energy is transmitted onto the surface of the earth in the form of seismic waves
• Earthquakes occur because of the sudden movement along faults within the earth
• Strength of an earthquake

  Measured by magnitude
• Extent of damage caused by an earthquake


  Measured by intensity
• Types of earthquakes


  • Tectonic
  • Volcanic
  • Man-made
• Focus


  Point of origin of an earthquake beneath the surface of the earth
• Epicenter


  Point directly above the focus
• Fault


  Crack in the Earth's crust between two big plates
• Types of plate boundaries

  • Divergent
  • Convergent
  • Transform-fault
• Divergent boundaries


  • Plates move away from each other
• Convergent boundaries


  • Plates move toward each other
• Transform-fault boundaries


  • Plates slide past each other
• The agency that monitors Earthquakes is the PHIVOLCS (Philippine Institute of Volcanology and Seismology)
• Earth


  Consists of four layers: crust, mantle, outer core, inner core
• Crust


  • Outermost layer of the Earth
  • 8 km thick under oceans, 35 km under continents
  • Composed of igneous, sedimentary and metamorphic rocks
  • Temperature ranges from lowest to 870°C
  • Solid in state
  • Continental Crust and Oceanic Crust
• Mantle


  • Second layer of the Earth
  • Thickness of 2,900 km
  • Made up of silicon, oxygen, magnesium, and iron
  • Temperature measures between 870°C to 4,400°C
  • Solid in state
  • Contains Asthenosphere region
  • Separated from crust by Mohorovicic discontinuity
• Outer Core


  • Layer surrounding the inner core
  • Thickness of 2,300 km
  • Composed of Liquid Iron and liquid nickel
  • Temperature ranges from 4,400°C -6,100°C
  • Liquid in state
  • Influences the Earth's magnetic field
  • Separated from mantle by Guttenberg discontinuity
• Inner Core


  • Center and innermost layer of the Earth
  • Thickness of 1,170 km
  • Made up of dense Iron and Nickel
  • Temperature is 6,600°C, hottest part of the Earth
  • Does not melt due to high pressure
• Layers of the Earth

  • Crust
  • Mantle
  • Outer Core
  • Inner Core
• Volcano


  A landform, may be a hill, a mountain, or just a fissure on the earth's crust through which molten rock from beneath reaches the surface
• Volcano


  • Vent
  • Crater
  • Lava
  • Conduit pipe
• Vent


  The opening through which volcanic materials escape
• Crater


  A funnel-shaped pit or depression formed after a volcano has stopped erupting
• Lava


  The molten rocks which have reached the earth's surface
• Conduit pipe


  Where magma passes through when it tries to escape
• Magma chamber


  Where magma is temporarily stored
• Parts of a Volcano

  • Vent
  • Crater
  • Lava
  • Conduit pipe
  • Magma chamber
• LAVA FLOW
• ASH CLOUD
• OPPE/MAIN VENT
• BRANCH PIPE/SIDE VENT
• MAGMA CHAMBER
• VOLCANIC CONE, BUILT UP OF ASH AND LAVA FROM PREVIOUS ERUPTIONS
• Active Volcano


  One which has erupted recently and may erupt in the near future
• Active volcanoes in the Philippines

  • Mayon Volcano
  • Pinatubo Volcano
  • Kanlaon Volcano
  • Hibok-hibok Volcano
  • Taal Volcano
• Dormant Volcano


  A volcano that has not erupted for a long time but may erupt again
• PHIVOLCS: Volcanoes


  • Mayon Volcano
  • Pinatubo Volcano
  • Kanlaon Volcano
  • Hibok-hibok Volcano
  • Taal Volcano
  • Bulusan Volcano
• Dormant Volcano


  A volcano that has not erupted for a long time but may erupt again
• According to PHIVOLCS, there are 300 dormant volcanoes in the country