### Nivi presentation_earth quake.pptx

1. EARTHQUAKE Presented by Niveditha Nethaji Grade -8A
2.  Earthquakes are the shaking, rolling or sudden shock of the earth’s surface.  They are the Earth's natural means of releasing stress.  Earthquakes usually last less than one minute.  Earthquakes cannot be predicted. What is an earthquake?
3.  There are about 20 plates along the surface of the earth.  The plates are all moving in different directions and at different speeds.  The plates crash together, pull apart or sideswipe each other commonly results in earthquakes. What causes an earthquake?
4. Primary Wave (P-Wave)  Fastest  first waves to arrive. Secondary Wave (S-Wave)  second fastest (~60%)  Move up and down  Travel slow Types of Earthquake waves
5.  It compresses and expands the ground.  Travels around 8km/second.  Travels through liquids and solids.  You may feel earthquake. Primary Wave (P-Wave)
6.  It moves the ground up and down or side to side.  Travels around 4.5km/second.  Travels through solids.  Usually cause more damage. Secondary Wave (S-Wave)
7.  Primary Wave (P-Wave) Which wave is faster?
8.  P wave can move through solid rock and fluids, like water or the liquid layers of the earth.  P-waves are compression waves that apply a force in the direction of propagation. ... The energy is thus less easily transmitted through the medium Why P waves are faster than S waves?
9.  A longitudinal wave is a wave in which particles of the medium move in a direction parallel to the direction that the wave moves.  This means that the particles move left and right. What is a longitudinal wave?
10.  sound waves.  ultrasound waves.  seismic P-waves. What are examples of longitudinal waves?
11.  Transverse waves are always characterized by particle motion being perpendicular to wave motion.  Ripples on the surface of water. Transverse waves
12.  Vibrations in a guitar string.  Electromagnetic waves Example- Light waves, microwaves, radio waves.  Seismic S-waves. What are examples of Transverse waves?