• Like
Upcoming SlideShare
Loading in...5

Thanks for flagging this SlideShare!

Oops! An error has occurred.



Published in Technology , Education
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
    Be the first to like this
No Downloads


Total Views
On SlideShare
From Embeds
Number of Embeds



Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

    No notes for slide


  • 1. Earthquakes Release Energy
  • 2. Seismic Waves
    • The vibrations caused by earthquakes
  • 3. Focus and Epicenter
    • Focus - the of an earthquake is the pint underground where the rocks first begin to move.
    • Epicenter - the point of the Earth’s surface directly above the focus.
      • Scientists often name an earthquake after the city that is closest to the epicenter
  • 4. Waves and Energy
      • Earthquakes produce three types of waves
        • Primary Waves
        • Secondary Waves
        • Surface Waves
  • 5. Primary Waves
    • These are the fastest seismic waves
    • Also called P waves
    • Average speed 5km/sec (3mi/sec)
    • Can pass through solids, liquids and gases
  • 6. Secondary waves
    • Also called S- Waves
    • Travel at about ½ the speed of P-waves
    • Start at the same time as P-waves
    • Can travel through solids (rocks) NOT through liquids or gases
  • 7. Surface Waves
    • Seismic waves that move along Earth’s surface, not through it’s interior
    • Make the ground roll or shake from side to side
    • Cause the largest ground movements and the most damage.
    • The slowest type of seismic waves
  • 8. Seismograph
    • An instrument that constantly records ground movements
    Read page 116 (B), using seismographs
  • 9. Locating Earthquakes
    • Scientist must have at least 3 seismic stations
      • Scientist find the difference between the arrival times of the P and S waves at each of the three stations
      • The time difference is used to determine the distance of the epicenter from each station. The greater the difference in time, the farther away the epicenter is.
      • A circle is drawn around each station, with a radius corresponding to the epicenters distance from that station. The point where the 3 circles meet is the epicenter
  • 10.