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Earth’s Crust in Motion. When the Earth’s plates are in motion, earthquakes may occur. Tier Word Motion-movement. STRESS. The movement causes stress in the crust. There are 3 types of stress in the crust Stress -pressure. Musical sliders. Tensional Stress (gum). Compressional Stress.
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When the Earth’s plates are in motion, earthquakes may occur. • Tier Word • Motion-movement .
STRESS • The movement causes stress in the crust. • There are 3 types of stress in the crust • Stress -pressure
What happens during an earthquake? • The stress builds and then releases. This is the energy in an earthquake. • An earthquake is the shaking and trembling that is caused by the movement of rock beneath Earth’s surface.
Faults • Earthquakes are caused by stress at fault lines. • A fault line is found at the boundaries of two different lithospheric plates. • (it’s the faults fault! ) • haaaaaaaaaaaa
Strike slip fault • Caused by shearing • Rocks slip past each other • San Andreas Fault
Normal faults -the land is pulling apart or stretching. • The tension in the crust increases until the rocks fracture. • One block of land slips downward • Fracture-break
Reverse (Thrust) Fault • Forms by compression • hanging wall slides up and over footwall • Formed Appalachian Mountains
http://science.howstuffworks.com/nature/natural-disasters/earthquake3.htmhttp://science.howstuffworks.com/nature/natural-disasters/earthquake3.htm
Safety Tips • Have an earthquake readiness plan. • make your home sturdier, such as bolting bookcases to wall studs, installing trong latches on cupboards, and strapping the water heater to wall • Locate a place in each room of the house that you can go to in case of an earthquake. It should be a spot where nothing is likely to fall on you. • Keep a supply of canned food, an up-to-date first aid kit, 3 gallons (11.4 liters) of water per person, dust masks and goggles, and a working battery-operated radio and flashlights. • Know how to turn off your gas and water mains. • .
Mountain Building • Takes millions of years • Caused by compression/converging forces • Formed by folding –bends in rock that form when compression shortens and thickens part of Earth’s crust
Mountain Building Cont. • Syncline dip • Anti-cline = peak rock bends into an arch • Plateau =large area of flat land elevated high above sea level
Tier words to Know for the Test and Beyond • Compress -squeeze • Geologic event (earthquakes, volcanoes) • Interior-inside • Motion -movement • Anything that starts with the prefix geo-earth • Volcanologist- studies volcanoes • Seismologist- studies earthquakes • Diverge -separate • Converge- come together • Transform- slip past • Stress –pressure/tension
Questions to Think About Essential Questions: • Can we predict earthquakes? Can we predict when volcanoes will erupt? • What do earthquakes and volcanoes tell us about what is happening inside the earth and on the surface? • Do you have to worry about a volcanic eruption or • earthquake where you live? Why or why not?
What students need to know for the long run • Unit Enduring Understandings: • Studying historical earthquakes and volcanic eruptions improves our understanding of earth's processes. • Although it is known where earthquakes and volcanic eruptions are likely to happen, there is currently no reliable way to predict precisely when an event will occur. • Volcanoes and earthquakes indicate the high temperatures and pressures that exist in earth's interior. • Volcanism(volcanic activity) and seismic(earthquake) activity vary across the globe
Common misunderstandings • What do students typically misunderstand? • Earthquakes don’t only occur when whole plates slide past each other. • Earthquakes don’t create a gap or hole in the earth's surface. • Earthquakes don’t occur at one depth. • Lava that erupts out of a volcano does not comes from earth's core. • Earthquakes don’t cause volcanic eruptions. • Plate boundaries are not the same as faults. • Lava does not come out of all volcanic eruptions
