Earthquake  Vocabulary
 

1. Earthquake-
   A sudden movement of the Earth's plates that can cause destruction. Earthquakes occur at plate boundaries when built up pressures in rocks suddenly release causing the plates to move along a fault line.
    
2. Earthquake belts-
   A) Circum-Pacific belt-Encircles the outer rim of the Pacific Ocean. This area is the most active for earthquakes and volcanoes in the world.
   B) Alpide belt-
   This earthquake belt runs from Western Europe to Central Asia.
    
3. Fault-
   A long crack in the Earth's crust.
    
4. Focus-
   The place in the Earth's crust where an earthquake occurs. This is usually found deep under the surface of the Earth.
    
5. Epicenter-
   The place on the Earth's surface directly above the focus.
    
6. Earthquake Waves-
   Also called seismic waves. They are caused by the rapid release of energy caused by movements in the Earth's crust.
   A) Compression waves-
   First and fastest waves produced in an earthquake. They are also called P (Primary) waves. They move in a jackhammer motion.
   B) Shear waves-
   Second waves to strike an area. Also called S (Secondary) waves. They travel slower than P waves. They move in an up and down roller coaster motion.
   C) Surface waves-
   These are the last waves to strike an area. They are the slowest waves and are confined to the surface of the Earth. They produce the most damage to man made materials.
    
7. Magnitude-
   Measurement of the intensity of an earthquake.
    
8. Richter Scale-
   Scale used to identify the strength of an earthquake. Richter scale runs from 1-9. Earthquakes with a 6 or above rating are considered powerful.
    
9. Seismograph-
   A graph showing the length and severity of an earthquake.
    
10. Strike-
    slip Fault/ San Andreas Fault-A strike-slip fault is located at a transverse plate boundary. The two plates slide by each other moving in opposite directions.
     
11. Tsunami-
    A very large wave produced from earthquakes, volcanic activity, or an under water landslide. These waves produce 30-100 foot high crests as they break onto the shoreline. They can produce enormous damage to seaside communities.