1. Formation of the Earth EARTHQUAKES

2.  An earthquake is a natural hazard caused by the sudden and rapid movement of a large volume of rock  Earthquakes are a way for the earth to release stress  More than a million earthquakes occur every year  Earthquakes can happen all over the nation, but are most likely to occur along the West Coast  Earthquakes usually last less than one minute  Earthquakes cannot be predicted! WHAT IS AN EARTHQUAKE

3.  There are about 20 plates that are constantly moving along the surface of the earth  As the plates move, they put forces on themselves and each other  When enough force is added, the earth’s crust snaps  When the snap occurs, stress is released as energy which moves through the earth in the form of waves  A fault is the area of stress in the earth where broken rocks slide past each other causing a crack in the earth’s surface THE CAUSES OF AN EARTHQUAKE

4.  The epicenter is the point at the surface directly above the focus  The focus is the location where the earthquake begins  The hypocenter is the point within the earth where the earthquake rupture starts  Seismic Waves are waves of energy that travel through the earth’s layers as a result of an earthquake PARTS OF AN EARTHQUAKE

5. THE PARTS OF THE EARTHQUAKE

6.  Surface waves: travel along the earth’s surface  Body waves: travel through the interior of the earth  Primary waves: compressed, longitudinal waves  Secondary waves: transverse waves SEISMIC WAVES

7.  Scientists use the Richter Scale to measure the intensity of an earthquake  Each one-point increase on the scale indicates ten times the amount of shaking and 33 times the amount of energy  The energy released by a large earthquake may be equal to 10,000 times the energy of the first atomic bomb.  4 Minor Earthquake  5 Moderate Earthquake  6 Strong Earthquake  7 Major Earthquake  8 Great Earthquake HOW TO MEASURE AN EARTHQUAKE

8.  DROP, COVER AND HOLD ON!  During an earthquake it is important to stay indoors until the shaking stops  Stay away from windows  If you’re outdoors, find a clear spot away from buildings, trees and power lines.  Always drop to the ground.  If you’re in a car, slow down and drive to a safe place. Stay in the car until the shaking stops. EARTHQUAKE SAFETY