Earth Quakes
An Earthquake is a movement of the earths lithosphere that occurs when rocks in the lithosphere shift releasing stored up energy. They occur because stress forces have been exceeded the strength of the rock. Earthquakes are the result of the plates moving, the occur upon a fault which is a break in a mass of rock along which movement occurs. The focus is where the rock occurs within the earth and the epicenter is the area right above the focus on the earths surface. There are three types of waves that are products of earthquakes: P, S, and Surface waves.
P waves (primary waves) are longitudinal waves which move through material and the cause materials to vibrate in the direction in which the waves are moving. They compres and expand the ground and can travel through solid and liquid.
S waves (secondary waves) are transverse waves s waves causes things to vibrate at right angles to the direction the waves move. They can not travel through liquids.
Surface waves are waves that develop when seismic waves reach the earths surface. Even though generally the move slower that p and s waves surface waves produce greater ground movements and more damage. Some are transverse and some are a rolling motion.
The Love and Rayleigh waves are surface waves
P waves (primary waves) are longitudinal waves which move through material and the cause materials to vibrate in the direction in which the waves are moving. They compres and expand the ground and can travel through solid and liquid.
S waves (secondary waves) are transverse waves s waves causes things to vibrate at right angles to the direction the waves move. They can not travel through liquids.
Surface waves are waves that develop when seismic waves reach the earths surface. Even though generally the move slower that p and s waves surface waves produce greater ground movements and more damage. Some are transverse and some are a rolling motion.
The Love and Rayleigh waves are surface waves
To measure earthquakes and pinpoint their epicenters, geologist record seismic waves using seismograpgs. The way earth quakes are measured are by a Moment Magnitude Scale which gives the amount of energy released by an earthquake. The scale that is used is the Richter scale which is a scale form 1-10. Another scale is the Modified Mercalli Scale which is a scale from 1-12 this scale isn't nearly as accurate because this scale is based on observations.
Pictures: http://blogs-images.forbes.com/moneybuilder/files/2011/08/earthquake.jpg
http://www.geo.mtu.edu/UPSeis/images/P-wave_animation.gif
http://www.geo.mtu.edu/UPSeis/images/S-wave_animation.gif
http://www.geo.mtu.edu/UPSeis/images/Love_animation.gif
http://www.geo.mtu.edu/UPSeis/images/Rayleigh_animation.gif
http://upload.wikimedia.org/wikipedia/commons/0/0f/Kinemetrics_seismograph.jpg
http://www.sdgs.usd.edu/publications/maps/earthquakes/images/RichterScale.gif
http://iema.illinois.gov/images/Mercalli.jpg
http://www.geo.mtu.edu/UPSeis/images/P-wave_animation.gif
http://www.geo.mtu.edu/UPSeis/images/S-wave_animation.gif
http://www.geo.mtu.edu/UPSeis/images/Love_animation.gif
http://www.geo.mtu.edu/UPSeis/images/Rayleigh_animation.gif
http://upload.wikimedia.org/wikipedia/commons/0/0f/Kinemetrics_seismograph.jpg
http://www.sdgs.usd.edu/publications/maps/earthquakes/images/RichterScale.gif
http://iema.illinois.gov/images/Mercalli.jpg