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Earthquakes and Mountain Building. Presented by Mrs.Tonya. Layers of the Earth. Crust. Mantle. Inner Core. Outer Core. Crust. 20 miles thick below continents 6.5 miles thick below oceans Thin outer layer that surrounds the mantle Rocky and brittle Less than 1% of earth’s volume.
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Earthquakes and Mountain Building Presented by Mrs.Tonya
Layers of the Earth Crust Mantle Inner Core Outer Core
Crust • 20 miles thick below continents • 6.5 miles thick below oceans • Thin outer layer that surrounds the mantle • Rocky and brittle • Less than 1% of earth’s volume
Mantle • 1,800 miles thick • Mostly solid but can slowly deform(plastic) • 84% of earth’s volume • 1000oC
Inner Core 758 miles in radius Solid 4300oC Outer Core 1,400 miles thick Liquid layer 3700oC Core
Math Trivia • The crust is 1% of the earth’s volume and the mantle is 84% of the earth’s volume. What percentage of the earth’s volume is the core? Answer: 15%
Tectonic Plates • Pieces of the crust and uppermost mantle that make up the lithosphere • Interconnecting pieces that fit together like a puzzle
Is it possible that all of the continents were connected to form one landmass? Tectonic plate activity
Theory • Similar species (fossils) • Matching layers of rock • Coastlines appearing to fit together
Movement of tectonic plates • Caused by convection currents(theory) • 3 types of movement
Normal fault • Tectonic plates are moving apart • Lithosphere is stretching
Reverse fault Tectonic plates are moving towards one another
Strike Slip fault Tectonic plates slide past one another
What causes mountains to be formed? • 2 tectonic plates collide • Slabs pile into one another • Causes crust to deform and elevate • Oreo demo
What causes a volcano? • 2 tectonic plates collide • 1 plate boundary is subducted or forced deeper into earth • Causes other slab to fold deeply • Hot magma can seep to surface of earth • Spreading of two plates can cause hot magma to rise to surface
What causes an earthquake? • The release of stored up energy as the plates move past each other • The energy moves outward from the fault in all directions in the form of waves • When the waves reach the earth’s surface this causes the ground to shake
Primary waves Compression waves Push and pull Slinky demo The fastest seismic wave
Secondary waves Shear waves Side to side motion Slinky demo Slower than primary wave
Love waves Surface waves Cause the most damage to buildings Travel the slowest of all seismic waves
How far is the earthquake? • Detect p-waves and s-waves on a seismograph • Calculate difference between waves
Calculate distance to earthquake • Distance = rate X time • Example You are traveling 30 miles/hour and you travel for 2 hours. What distance have you traveled? Distance = (30 miles/hour)x(2 hours) = 60 miles
Math Trivia • The Himalayan Mountains formed when the Indian Plate crashed into the Eurasian Plate. Today the two plates are still colliding and the Himalayas continue to rise. If the first person climbed Everest in 1953 and the mountains grow about .5 inches per year. How many more inches would you have to climb if you climbed Everest in 2009? Answer: 28 inches