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Earthquakes!. 8SCIENCE. Welcome Back!. Goal- Students will explain how earthquakes result from the movement of plates on Earth’s surface. Remember…. What are the three types of plate boundaries?. What is the relationship between earthquakes and plate boundaries?. What is an earthquake?.
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Earthquakes! 8SCIENCE
Welcome Back! Goal- Students will explain how earthquakes result from the movement of plates on Earth’s surface.
Remember… • What are the three types of plate boundaries? What is the relationship between earthquakes and plate boundaries?
What is an earthquake? Review: • Sections of the Earth’s crust (tectonic plates) move and cause rocks to bend and stretch • If there is enough force the rocks will break, release energy and cause vibrations = earthquake
Where are these tectonic plates found? • These plates are made of Earth’s crust, and all oceans and land mass sit on these layers: • Crust • Mantle • Outer core • Inner core
Let’s Listen… Crust and Mantle
Layers of the Earth • Click here for a great website about the Earth's structure and for other information about earth processes • Here is another great site with video clips / animations! • These 4 main layers each have a different composition: • The crust is thin and rocky • The crust sits on top of the mantle, which flows at a rate of a few cm/year • The deeper layers are composed of heavier materials at high pressure
What is an earthquake? • The Earth’s crust is in constant motion because of forces inside the earth • Sections of the crust (plates) move, puttingforce on the plates • 3 types of force: • Compression • Tension • Shear
These forces form…faults! • Compression = force that pushes together • Tension = force that pulls apart • Shear = force that moves past the other ↑↓ • These forces cause rocks to break and move along surfaces called faults
Different Forces produce Different Faults • To see the above in motion: • When rocks are stretched they may break • When these rocks break, energy is released along fault surfaces, also called an earthquake!
Got it? • Earthquake Video Clip • Complete Reinforcement Ch 8- You can use pp. 210-213 in your text to help you.