EarthquakesEarthquakes AMSTIAMSTI. EarthquakeEarthquake Shaking & vibrating of earth Natural event...
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Transcript of EarthquakesEarthquakes AMSTIAMSTI. EarthquakeEarthquake Shaking & vibrating of earth Natural event...
EarthquakesAMSTI
Earthquake• Shaking & vibrating of
earth
• Natural event
• Large sudden release of energy along cracks of Earth's crust
• Beyond human control
• Studied by seismologist
• Monitored by satellites
Myths
• Throughout history, people have had imaginative explanations for why earthquakes happen
• Giant catfish holding Earth
• Giant frog jumping on Earth
• Giant tortoise carrying Earth
Waves
• Travel in all directions from center of circle
• Surface waves (up & down)
• Body waves: P & S waves (push/pull & side/side)
• S waves don't travel through liquids
Speeds of Waves
• Each has a constant speeds; but P wave is faster
• Larger difference between P & S wave arrival means further the seismograph station is from location of EQ
EQ resistant homes
• Foundation connected to rock deep underground
• Walls & beams tied together
• Liquid concrete sprayed on brackets
Seismographs• Instrument that records
EQ- located all over the world
• 3 different locations needed to locate epicenter
• Seismogram- paper the vibrations recorded on
• Each tic = 1 minute if each day
• Pen moves as the vibrations move
Tsunamis
• Huge wave
• Can be caused by EQ
• Can travel thousands of miles
Focus & Epicenter
• Focus- point where EQ begins
• Epicenter- point on surface above focus
Canines to the Rescue
• Dogs have stronger senses- especially for smell-sniff the air
• National Association for Search & Rescue- 1500 handlers
Ring of Fire
• Circum-Pacific Belt
• Consists of a chain of EQ around Pacific Ocean
• Due to deep sea trenches
• Common locations- California, Alaska & Japan
Richter Scale
• Named after Charles Richter
• Measures magnitude of EQ by measuring the "swing" of the wave
• Measures 1-8+
Worldwide Statistics• Less than 3- 9000 per day
• 3-3.9- 49000 annually
• 4-4.9- 6200 annually
• 5-5.9- 800 annually
• 6-6.9- 120 annually
• 7-7.9- 18 annually
• 8+ - 1 annually
Earth's Interior
• Layers: Core, Mantle & Crust
• 2 types of crust: Oceanic & Continental
Sonar
• Sending & receiving an echo
• Used to map the interior of the Earth & the floor of the ocean
Tectonic Plates
• Earth's crust is broken into segments that fit together like a puzzle
• Plates float over the mantle
• Plates move which can cause EQ
Movement of Plates
• Convergent- 2 plates push together- forms mountains
• Divergent- 2 plates pull apart- forms trench or valley-dense oceanic plate sinks under continental plate
• Transform- 2 plates slide past each other- no new land is formed
San Andreas Fault• California
• Rocks have jagged surfaces that hook on each other which wear down after the EQ ruptures
• Rocks that bend are called ductile
• Fences & rivers change shape as result of moving plates
Theory of Pangea
• Belief that all continents were once a single large landmass- super continent
• Proof? Sides look like they fit together like a puzzle, identical fossils separated by oceans, scratches on glaciers & mountain ranges line up on different continents
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