1. Energy Transformation in the form of Seismic Waves
Earthquakes and waves
Energy Transformation in the form of Seismic Waves

2. Earthquakes
Earthquakes transfer stored energy into kinetic energy in form of seismic waves.
Waves are an oscillation or vibration that transfers energy

3. Earthquake Identification and Location
Earthquakes are located and identified by their focus, epicenter and magnitude
Focus: The point where the fracture in rock occurs, (under ground).
Epicenter: The point, on land, directly above the focus point.
Magnitude: The amount of energy or destruction that has been released/caused

4. Magnitude
Magnitude is measured with 2 different types of rating scales.
1. Richter Scale: Measures the total amount of energy released by the earthquake.
Magnitude 7 or greater is a major quake
Magnitude 6 or less is a minor quake
Magnitude 2 or less is a micro quake or tremor

5. Magnitude Continued 2. Mercalli Scale:
Measures the degree of destruction that has been caused. This is a scale that is far more subjective in nature.
Mercalli scale rates on a scale of I – XII
I is little damage and XII is extreme destruction

6. Seismic Waves Primary or P waves Secondary or S waves
Fastest moving seismic wave
Arrive at recording stations first
Moves in a spring like way
Travel through both liquid and solid material
Slower moving wave
Arrives at recording stations after the P wave
Moves in an up and down way
Cause buildings to shake
Travels through solid material only

7. Primary and Secondary Waves
P waves oscillate through compression and expansion, in the same direction of movement
S waves oscillate in a direction that is perpendicular to direction of movement

8. L-Waves L waves are also known as surface waves
They are the slowest but most destructive waves
They are the waves that cause surface rolling

9. Seismic wave movement through earth’s layers

10. Distance to Epicenter
Seismologists determine the distance to the earthquake’s epicenter through analyzing the difference in arrival times at the recording station.
When arrival times are close, with little difference, the distance to the epicenter is very small.
The greater the difference in arrival times, the further away the epicenter is
Use information from 3 recording stations to triangulate the location

11. Triangulation

13. Location of Earthquakes
3 major locations where earthquakes occur
Ring of Fire
Seismic activity is
due to the
subduction of
ocean and
continental crust

14. Earthquake location continued
2. Mid ocean ridge Seismic activity due to the divergent plate boundary

15. Earthquake locations continued
3. The Eurasian-Melanesian Mountain Belt