sci 10 Q1

• Secondary plate (minor)


  Any plate with an area that are less than 20 million km^2 but greater than 1 million km^2 (e.g. Philippine plate, Indian plate, Scotia plate)
• Tertiary plate


  Any plate with an area that are less than 1 million km^2
• Earthquake


  Sudden slip on a fault
• Focus


  The point within the earth where the release of energy happens
• Epicenter


  The location on the surface of the earth directly above the focus
• Seismograph


  Used to record the motion of the ground
• Seismic waves


  Waves of acoustic energy that travel through the earth
• Types of seismic waves

  • Body waves
  • Surface waves
• Body waves


  Seismic waves that move through the interior of the earth
• Primary waves (p-wave)


  The fastest seismic waves that can move through solid, liquid, or gas
• Secondary waves (s-wave)


  Slower than p-waves, also called shear waves because they don't change the volume of the material through which they propagate, travel through solid materials only
• Surface waves


  Can only travel on the surface of the earth and arrive after the body waves
• Love waves


  Shear waves trapped near the surface
• Rayleigh waves


  Have rock particle motion similar to the water particle in the ocean
• Triangulation method


  Uses distance information from three seismic stations to locate the earthquake epicenter by drawing circles on a map around each station and finding the intersection point
• Seismologist


  Determines the distance to the earthquake epicenter by multiplying the difference in the arrival time of p-wave and s-wave in seconds by 8 km/s
• Theory of plate tectonics

  Pieces of Earth's Lithosphere are in constant motion, driven by convection currents in the mantle
• Convection current


  Formed by rising of hot magma near the core towards the surface, while cooler magma near the crust sinks, setting up current that causes the plates to move
• Convergent plate boundary


  A plate boundary where two plates move toward each other, causing compression stress
• Geological features/events in convergent boundary

  • Volcanoes
  • Volcanic island arc
  • Trench
  • Continental volcanic arc
  • Mountain ranges
  • Earthquakes
• Types of convergent plate boundary

  • Oceanic-oceanic
  • Oceanic-continental
  • Continental-continental
• Oceanic-oceanic convergent boundary


  Two oceanic slabs converge and subduct the other, resulting in volcanoes, volcanic island arc, trench, and earthquakes
• Oceanic-continental convergent boundary


  Denser oceanic lithosphere sinks into the asthenosphere (subduction), resulting in continental volcanic arc, trench, and earthquakes
• Continental-continental convergent boundary


  No subduction happens, resulting in mountain ranges and earthquakes
• Divergent plate boundary


  Two plates that move away from each other, creating a tension zone causing shallow earthquakes and new crust