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EaRtHqUaKeS !!! PowerPoint Presentation
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EaRtHqUaKeS !!!

EaRtHqUaKeS !!!

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EaRtHqUaKeS !!!

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  1. EaRtHqUaKeS!!!

  2. What do earthquakes feel like? San Francisco Earthquake of 1989

  3. Seismology: the study of earthquakes What else is The Ring of Fire known for? Most earthquakes take place near the edges of tectonic plates (most active earthquakes occur along the plates surrounding the Pacific Ocean)

  4. What Causes Earthquakes? As tectonic plates push, pull or scrape against each other, stress builds up along faults until the rocks finally move A fault is a break in the Earth’s crust where plates slide, push or pull against each other

  5. What Causes Earthquakes? Deformation is the change in the shape of rock in response to stress. Rock can deform in 2 ways:- plastic- elastic

  6. ***Write this in your glossary!***Plastic Deformation THIS DOES NOTLEAD to EARTHQUAKES!!!! Stress causes the crust on one side of a fault bend like clay

  7. Elastic Deformation THIS DOESLEAD to EARTHQUAKES!!!! Rock can only stretch so far before it will break Like a rubber band, when it breaks, energy is released and the broken pieces return to their unstretched shape causing energy to spread through the earth in waves.

  8. Are All Earthquakes the Same? ***Copy this chart in your notebook!*** No. Depending on the type of plate boundary, earthquakes can be strong or weak.

  9. How Do Earthquakes Differ? ***Write down the part in red*** Not all earthquakes are the same. The type of earthquake that occurs depends on the type of plate motion and fault type there is!

  10. Transform = Strike-Slip ***Write the definition of strike slip in your glossary*** • If two plates have a transform motion, they will probably have a strike-slip fault between them • A strike-slip fault is when two blocks of crust slide past each other horizontally • These types of earthquakes are moderate and shallow

  11. Convergent = Reverse ***Write the definition of in your glossary*** • If two plates have a convergent motion, they will probably have a reverse fault between them. • A reverse fault happens when two blocks of crust are pushed up against each other and they slide vertically. • These types of earthquakes are usually strong and deep.

  12. Divergent = Normal ***Write the definition of in your glossary*** • If two plates have a divergent motion, they will probably have a normal fault between them • A normal fault occurs when two blocks of crust are pulled away from each other and slide vertically • This type of earthquake is usually weak and shallow

  13. Earth on the Move

  14. Earthquake Waves • All earthquakes release energy called seismic waves • Scientists measure seismic waves to determine the scale (how big or small) an earthquake is • Most people use the Richter scale to measure earthquake seismic waves

  15. How Seismographs Work the pendulum remains fixed as the ground moves beneath it

  16. Typical Seismogram

  17. How Are Earthquakes Measured? This is a seismograph It is an instrument located at or near the surface of the Earth that records seismic waves

  18. What Scale is Used to Measure the Strength of an Earthquake? * Right where the earthquake begins The Richter Scale

  19. How are Earthquakes Measured? Richter Scale

  20. Primary Waves (P Waves) ***Write the definition in your glossary*** A type of seismic wave that compresses and expands the ground. Primary waves are longitudinal waves. They can travel through liquids. The first wave to arrive at an earthquake. P comes before S in the alphabet.

  21. Secondary Waves (S Waves) ***Write the definition in your glossary*** A type of seismic wave that moves the ground up and down or side to side. These are transverse waves. They cannot go through liquids. They are the second wave people feel. They are sometimes called the aftershock.

  22. Comparing Seismic Waves

  23. Surface Waves ***Write the definition in your glossary*** • Move along the Earth’s surface • Produces motion in the upper crust • Motion can be up and down • Motion can be around • Motion can be back and forth • Travel more slowly than S and P waves • More destructive

  24. How do scientists calculate how far a location is from the epicenter of an earthquake? Scientists calculate the difference between arrival times of the P waves and S waves The further away an earthquake is, the greater the time between the arrival of the P waves and the S waves

  25. Scientists used what we know about S and P waves to figure out the layers of the Earth. What information may have helped them to determine which parts of the Earth are solid and which are liquid?

  26. Locating Earthquakes

  27. Locating Earthquakes

  28. Locating Earthquakes

  29. Focus – point inside the Earth where an earthquake beginsEpicenter – point on Earth’s surface above focus