earthquakes

earthquake

sudden violent shaking vibration and trembling on the crust caused by release of stress along fault lines or by volcanic activity

aftershocks

minor vibrations after main earthquake

foreshocks

minor vibrations before the main earthquake

deep focus

400km below earths surface

shallow focus

depth of less than 70km bellow the surface

intermediate focus

between 70-300km bellow the surface

where most earthquakes occur

fault lines known as seismic belt

most famous seismic belt

pacific ring of fire

most famous fault line 

san andreas fault california

seismograph

detects measures and records seismic waves force and duration

primary/compressional

travel through earths interior
solid and liquid/molten material

5km/second

secondary

also travel through earths interior
solid material 
2.5km/second

surface

travels along the surface or just below
up and down side to side 
slowest type 
almost entirely responsible for destruction
love wave and rayleigh wave

richter scale

measures the strength or magnitude

destruction and devastation caused by earthquakes

injury and loss of life
property damage
liquefication
landslides rockslides avalanches
fire
tsunamis

action to limit destruction and devastation 

buildings and infrastructure are reinforced with steel and springs
increased emergency planning and managment