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Published byElmer Crawford Modified over 9 years ago
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Daily Review #4 Describe the 4 different pieces of evidence to support continental drift How does convection cause a plate to move? Discuss your answer to the writing prompt about what you think will happen to the continents in 100 million years.
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Plate Tectonics Movement ◦ cm/yr ◦ Measured by GPS Interact at boundaries – 3 types ◦ Collide ◦ Separate ◦ Slide past Earthquakes can occur at all
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Convergent Boundary Plates collide Continental- continental ◦ Create mountains Continental-oceanic ◦ Oceanic sinks ◦ Subduction zone and trench ◦ Remelted, recycled Oceanic-oceanic ◦ One subducts
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Transform Boundary Plates slide past each Not usually smooth Larger, more frequent earthquakes
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Earthquakes What are they? What is it like? Seismologist Where? ◦ Plate boundary ◦ Rarely in middle of continent ◦ Occur at or create faults ◦ Varying depths ◦ Focus Epicenter
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How are earthquakes measured? Richter scale ◦ Strength (magnitude) ◦ Measuring ground motion ◦ Used by the media Moment magnitude ◦ More precise ◦ Measures the energy released ◦ Measured at the epicenter ◦ Used by scientists
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Largest Recorded Earthquakes Recent earthquakes
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Imaging of Earthquake Waves Seismograph ◦ Shows local movement ◦ 3 main waves 1.P wave 2.S wave 3.Surface waves
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Finding the Epicenter Distance vs. time graph is constant ◦ Closest has smallest time difference Measure time difference on local seismograph ◦ Compare to graph ◦ Find distance Repeat for multiple locations
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Finding Epicenter cont. Use distances found Draw a circle from each site Overlap = epicenter
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Daily Review #5 How are convergent and transform boundaries similar? Different? Give a current example of a convergent boundary and what is being formed there What is an epicenter and how is it found? What kind of damage can an earthquake cause and how do you think we could prevent that damage?
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Elastic Rebound Hypothesis Energy builds Energy released ◦ Travel as waves Rocks return to original shape, but different locations
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Earthquake Waves P waves ◦ First detected ◦ Back-and-forth S waves ◦ Side-to-side ◦ Slower, arrive later
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Surface ◦ Rolling ◦ Side-to-side ◦ Slowest ◦ More destructive Aftershocks Foreshocks
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Earthquake Hazard Map
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Earthquake Prediction Not exact Seismic gaps ◦ Area of fewer earthquakes ◦ Likely location of future earthquake ◦ Used to predict 1989 San Francisco Past frequency
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Destruction from Earthquakes Liquefaction ◦ Mixing soil with underground water ◦ Sinkholes Landslides Fire ◦ Broken gas and electrical lines ◦ Lack water to fight Building and highway damage
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Tsunami Cause ◦ Underwater earthquake ◦ Ocean floor movement Massive waves Closer to shore ◦ Slows ◦ Increases in height
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Tsunami warning system Only a few a year Most recent (major) ◦ Indonesia (Dec. 2004) ◦ Japan (Mar. 2011) Seiche
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