Earthquakes

Earthquakes Facts Stress builds up in the cracks in the ground Shaking and trembling of the earth’s crust. Is an EVENT not a FORMATION on earth! Stress builds up in the cracks in the ground When the rock boundaries slips/gives it releases energy! The waves travel in all directions More than 1,000,000 quakes occur a year Earthquakes continue until all the energy is used up

Earthquakes Parts EPI CENTER- FOCUS- underground point of origin “EPI” means outer Point ABOVE where quake starts (focus) most violent shaking occurs here! Energy travels from focus FOCUS- underground point of origin The three main types of seismic waves are: P, S, & Surface (L) waves

Earthquakes Waves P Waves Primary waves Arrive first at the epicenter Can travel through solids, liquids, & gases They are push-pull waves Travel in straight line

Earthquakes Waves S Waves Secondary waves Can travel through solids, but NOT through liquids & gases Move in up-down motion

Earthquakes Waves L Waves Surface (Land) waves Slowest moving seismic waves Travel on top of Earth’s surface Cause most of damage to Earth bend & twist the surface

Seismo-- Seismic wave-earthquake waves Seismo graph-measures and detects seismic waves Seismo gram- Paper record of waves Seismo logist- scientist who study earthquakes

How bad was the Quake?? Mercalli Scale Richter Scale a scale that determines intensity of quake based upon people, damage, & loss 12 levels measured on amount of damage caused Richter Scale a scale that determines intensity of Seismic waves 10 levels measured on amount of damage caused Above a 6 is very destructive

Ring of Fire an area of frequent earthquakes & volcanic eruptions surrounding the Pacific Ocean.

90% of the world's earthquakes occur along the Ring of Fire. 40,000 km horseshoe shape The Ring of Fire has 452 volcanoes 90% of the world's earthquakes occur along the Ring of Fire.