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Bell Ringer. Open book to page 130-135 Answer the following questions: Where do earthquakes occur and what is a fault? What causes earthquakes? What is a seismic wave? Compare and contrast the 3 different types of seismic waves. Where do earthquakes occur and what is a fault?.
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Bell Ringer Open book to page 130-135 Answer the following questions: Where do earthquakes occur and what is a fault? What causes earthquakes? What is a seismic wave? Compare and contrast the 3 different types of seismic waves
Where do earthquakes occur and what is a fault? • A fault is a break in the Earth’s crust. • Most earthquakes take place near the edges of tectonic plates (fault lines). • Look at the map and notice where most recorded earthquakes occur.
What causes earthquakes? • During an earthquake, the rock breaks apart and/or the pressure between the two plates is released. • The energy that was stored in the rocks is given off in three types of waves. • The plate boundaries are made up of many faults, and most of the earthquakes around the world occur on these faults. Since the edges of the plates are rough, they get stuck while the rest of the plate keeps moving. Finally, when the plate has moved far enough, the edges unstick on one of the faults and there is an earthquake.
What is a seismic wave? • A seismic wave is a wave of energy that travels through the Earth and away from an earthquake in all directions.
Compare and contrast the 3 different types of seismic waves • Body Waves travel through the Earth: • P waves (Primary waves, pressure waves) – Travel through solids, liquids and gases. P. 134, figure 4 shows that P waves are longitudinal waves. Fastest and are first. Back and forth direction. • S waves (Secondary waves, shear waves) – Unable to travel through liquids. P. 134, figure 4 shows that S waves are transverse waves. Slower and come second. Side to side direction. • Surface Waves travel on the surface of the Earth: • Can be both longitudinal and transverse • Travel slower and are more destructive