Download - Plate tectonics, volcanoes, and earthquakes
Plate tectonics, volcanoes,and earthquakes
Ken HudnutKen HudnutU. S. Geological SurveyU. S. Geological Survey
Mr. Hajek’s 4th-grade classroomParadise Canyon Elementary SchoolLa Canada, California 3 October 2003
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Plate tectonics, volcanoesPlate tectonics, volcanoesand earthquakesand earthquakes
• Part 1Part 1 - plate tectonics - plate tectonics
• Part 2Part 2 - volcanoes - volcanoes
• Part 3Part 3 - earthquakes - earthquakes
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QuickTime™ and aAnimation decompressorare needed to see this picture.
Movie by T. Atwater, UCSB
Part 1. Plate TectonicsPart 1. Plate Tectonics
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Motion betweenthe plates causesearthquakes andvolcanoes
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Earthquakes and volcanoes are Earthquakes and volcanoes are driven by plate tectonic motiondriven by plate tectonic motion
• As a plate subducted, As a plate subducted, the Cascades the Cascades volcanoes and San volcanoes and San Andreas fault were bornAndreas fault were born
• The subducting plate The subducting plate melts and the magma melts and the magma rises up to form rises up to form volcanoesvolcanoes
• The plates sliding past The plates sliding past each other make the each other make the active transform faultsactive transform faults
Movie by T. Atwater, UCSB
QuickTime™ and aAnimation decompressorare needed to see this picture.
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Worksheet on Worksheet on Plate EdgesPlate Edges
• Plate edges are of three typesPlate edges are of three types
• Plates pull away from each otherPlates pull away from each other
• Plates push towards each otherPlates push towards each other
• Plates slide past each otherPlates slide past each other
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Part 2. VolcanoesPart 2. Volcanoes
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Eruption of Stromboli, Italy
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Motion betweenthe plates causesearthquakes andvolcanoes
This is really bad news for people (like us!) living around the Pacific Rim, also known as the Ring of Fire
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Why do volcanoes erupt?Why do volcanoes erupt?
• Pressure builds up Pressure builds up because of heat and because of heat and trapped gas bubblestrapped gas bubbles
• Cracks open and lava, Cracks open and lava, steam and ash blast outsteam and ash blast out
• Sticky magma makes Sticky magma makes tall cone-shaped tall cone-shaped volcanoes (like Merapi)volcanoes (like Merapi)
• Runny magma makes Runny magma makes low, broad volcanoes low, broad volcanoes (like Kilauea, Hawai’I)(like Kilauea, Hawai’I)
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MerapiMerapivolcano,volcano,JavaJava
Strato-volcanoeserupt igneous rocks!
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WestdahlWestdahlvolcano,volcano,AlaskaAlaska
QuickTime™ and aBMP decompressorare needed to see this picture.Volcanoes inflatewith magma, anddeflate with lava
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Worksheet on Worksheet on Ring of FireRing of Fire
• Plates crash into each other, causing Plates crash into each other, causing high mountains and low ocean floor high mountains and low ocean floor called trenchescalled trenches
• Deepest trench is the Marianas (esp. at the Deepest trench is the Marianas (esp. at the ‘Challenger Deep’ location shown on map)‘Challenger Deep’ location shown on map)
• Highest mountain is Mt. EverestHighest mountain is Mt. Everest
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Worksheet: hot spot track - islands cool, erode, & sink
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Part 3. EarthquakesPart 3. Earthquakes
Earthquakesare a globalproblem
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Earthquakes are driven by plate Earthquakes are driven by plate tectonic motiontectonic motion
• In the past 5 million In the past 5 million years, this motion years, this motion has been steady at has been steady at about 2 inches per about 2 inches per year year (that’s 15 feet (that’s 15 feet per century or 30 per century or 30 miles per million miles per million years!)years!)
• Yes, LA will be in Yes, LA will be in San FranciscoSan Francisco
• No, LA will not fall No, LA will not fall into the seainto the sea
Movie by T. Atwater, UCSB
QuickTime™ and aAnimation decompressorare needed to see this picture.
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Earthquakes are Earthquakes are not onlynot only California’s problem California’s problem$30M of oil each day!
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Houston, we have a problem…Houston, we have a problem…
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Southern California is the nation’s most Southern California is the nation’s most dangerous place for earthquakes - why?dangerous place for earthquakes - why?
Silver linings:State-of-the-art earthquake monitoring arraysMany of the world’s best researchers work within this natural laboratory
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The San Andreas faultThe San Andreas fault
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San Andreas faultSan Andreas fault• Most of the plate Most of the plate
boundary motionboundary motion• 1685, 1812, 1857 eq’s1685, 1812, 1857 eq’s
• Big Bend compressionBig Bend compression• 1971 Sylmar (M 6.7)1971 Sylmar (M 6.7)• 1994 Northridge (M 6.7)1994 Northridge (M 6.7)
• SoCal is now heavily SoCal is now heavily ‘wired’ (much like ‘wired’ (much like Japan & Taiwan)Japan & Taiwan)• SeismicSeismic• GPSGPS
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GPS
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‘A rip in the desert canvas’- Los Angeles Times
Katherine Kendrick, USGS
Chris Walls, Earth Consultants International
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Flying the fault line…Flying the fault line…
QuickTime™ and aDV/DVCPRO - NTSC decompressorare needed to see this picture.
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Conclusions:Conclusions: • Earth is a very active Earth is a very active planet - that’s both a planet - that’s both a good and bad thinggood and bad thing
• Humans can survive Humans can survive despite natural hazards - despite natural hazards - tragic losses from tragic losses from volcanoes & earthquake volcanoes & earthquake are not inevitableare not inevitable
• Natural beauty results Natural beauty results from plate tectonics - we from plate tectonics - we can study & understand can study & understand the world around usthe world around us