Earthquakes!
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Transcript of Earthquakes!
Earthquakes!8SCIENCE Tues. April 5
What is an earthquake?
Review:• Sections of the Earth’s crust (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 plates found?• These plates are made of Earth’s crust • Review layers of the Earth: animation– Crust– Mantle – Outer core– Inner core
What is an earthquake?• Earth’s crust is in constant motion because of forces
inside the earth • These cause sections of the crust (plates) to move which
puts force on the plates• 3 types of force:– Compression– Tension– Shear
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 and
an earthquake will result• When they break, energy is released along
fault surfaces, also called an earthquake!
FORCE FAULT MOVEMENT
TENSION NORMAL Rocks move down
COMPRESSION REVERSE Rocks move up
SHEAR STRIKE – SLIP Rocks do not move up down but past each other