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Earthquakes
<ul><li>Earthquakes :  Vibrations  (seismic waves) within Earth materials are produced by the rapid release of  energy </l...
<ul><li>The actual place underground where the rocks break producing vibrations is called the  focus </li></ul><ul><li>The...
 
<ul><li>Tension Force :  </li></ul><ul><li>stretching  or  pulling  force </li></ul><ul><li>Makes a  normal  fault </li></...
Normal Fault http://www.geo.uib.no/jordskjelv/index.php?topic=earthquakes&lang=en
<ul><li>Compression Force :  </li></ul><ul><li>force  pushing  something  together </li></ul><ul><li>Makes a  reverse  fau...
Reverse Fault http://www.geo.uib.no/jordskjelv/index.php?topic=earthquakes&lang=en
 
<ul><li>Shear Force :  </li></ul><ul><li>a system of forces that operates against a body from different sides </li></ul><u...
Strike-Slip Fault http://www.geo.uib.no/jordskjelv/index.php?topic=earthquakes&lang=en
<ul><ul><li>Movement along faults :  occurs when the energy exceeds the friction holding the sides of the fault together a...
<ul><li>Originate at the  focus  and travel outward in all directions </li></ul><ul><ul><li>Foreshocks :  small earthquake...
Seismic Waves
<ul><ul><li>P waves  (primary waves) Compressional wave </li></ul></ul><ul><ul><ul><li>Particles move back and forth in th...
<ul><ul><li>S wave  (secondary wave, shear wave) </li></ul></ul><ul><ul><ul><li>Particles move at  right angles  to the di...
<ul><ul><li>L wave  (long wave, surface wave, ground wave) </li></ul></ul><ul><ul><ul><li>Particles move in  elliptical  o...
 
How do we Measure Earthquakes? <ul><li>Earthquake waves are recorded by a  seismograph  and the recording of waves on pape...
How do we Measure Earthquakes? <ul><ul><li>Intensity  – a measure of the  effects  on an earthquake at a particular  locat...
<ul><li>Modified Mercalli intensity scale :  An estimate of the  intensity  based on observation of actual  damage </li></...
 
<ul><li>Richter Scale :  Measures the  amplitude  of earthquake waves on  seismograms </li></ul><ul><ul><ul><li>Scale from...
 
 
<ul><li>Locating the epicenter </li></ul><ul><ul><ul><li>Lag time  between the arrival of the  P wave and the S wave  to t...
 
Earthquake Dangers <ul><li>Most injuries and deaths are caused by  falling objects   and most property damage results from...
 
Tsunami—December 2004 http://www.bedford.k12.ny.us:16080/flhs/science/images/tsunami2004/
Earthquake Dangers <ul><ul><li>Seiche :  rhythmic  sloshing  of small bodies of water </li></ul></ul>A seiche is the slosh...
<ul><ul><li>Liquefaction :  unconsolidated materials that are water saturated may turn to a fluid causing some underground...
<ul><ul><li>Landslides </li></ul></ul>Earthquake Dangers
Earthquake Safety <ul><ul><li>Protect yourself from falling objects ( GET UNDER SOMETHING ) or stand in a hallway or doorw...
 
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Water Cycle

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Transcript of "Water Cycle"

  1. 1. Earthquakes
  2. 2. <ul><li>Earthquakes : Vibrations (seismic waves) within Earth materials are produced by the rapid release of energy </li></ul><ul><ul><li>Earth’s crust is in constant motion because of tectonic forces </li></ul></ul><ul><ul><li>Earth’s crust can store elastic energy </li></ul></ul><ul><ul><li>When forces exceed the elastic limits and structural strength of the rocks, the rocks will break and/or move producing vibrations that travel outward in all directions </li></ul></ul>What is an Earthquake?
  3. 3. <ul><li>The actual place underground where the rocks break producing vibrations is called the focus </li></ul><ul><li>The place on the surface directly above the focus is called the epicenter </li></ul>Earthquakes
  4. 5. <ul><li>Tension Force : </li></ul><ul><li>stretching or pulling force </li></ul><ul><li>Makes a normal fault </li></ul>What types of forces are created?
  5. 6. Normal Fault http://www.geo.uib.no/jordskjelv/index.php?topic=earthquakes&lang=en
  6. 7. <ul><li>Compression Force : </li></ul><ul><li>force pushing something together </li></ul><ul><li>Makes a reverse fault </li></ul>What types of forces are created?
  7. 8. Reverse Fault http://www.geo.uib.no/jordskjelv/index.php?topic=earthquakes&lang=en
  8. 10. <ul><li>Shear Force : </li></ul><ul><li>a system of forces that operates against a body from different sides </li></ul><ul><li>Makes a strike-slip fault </li></ul>What types of forces are created?
  9. 11. Strike-Slip Fault http://www.geo.uib.no/jordskjelv/index.php?topic=earthquakes&lang=en
  10. 12. <ul><ul><li>Movement along faults : occurs when the energy exceeds the friction holding the sides of the fault together and is suddenly released . </li></ul></ul><ul><ul><li>Movement of magma (volcanic) </li></ul></ul><ul><ul><li>Volcanic eruptions </li></ul></ul>What causes Earthquakes?
  11. 13. <ul><li>Originate at the focus and travel outward in all directions </li></ul><ul><ul><li>Foreshocks : small earthquakes that come before a major earthquake </li></ul></ul><ul><ul><li>Aftershocks : Are adjustments in the crust after in earthquake </li></ul></ul><ul><ul><ul><li>Smaller than main earthquake, but can cause as much or more damage. They can continue for weeks to months . Not every earthquake produces aftershocks </li></ul></ul></ul>Seismic Waves
  12. 14. Seismic Waves
  13. 15. <ul><ul><li>P waves (primary waves) Compressional wave </li></ul></ul><ul><ul><ul><li>Particles move back and forth in the same direction as the wave </li></ul></ul></ul><ul><ul><ul><li>Travels the fastest </li></ul></ul></ul><ul><ul><ul><li>Can pass through solids and liquids (gases also) </li></ul></ul></ul><ul><ul><ul><li>Does not cause damage </li></ul></ul></ul>3 Types of seismic Waves
  14. 16. <ul><ul><li>S wave (secondary wave, shear wave) </li></ul></ul><ul><ul><ul><li>Particles move at right angles to the direction of the wave </li></ul></ul></ul><ul><ul><ul><li>Travels slower than P waves </li></ul></ul></ul><ul><ul><ul><li>Can pass through solids only </li></ul></ul></ul><ul><ul><ul><li>Does not cause damage </li></ul></ul></ul>Types of Waves
  15. 17. <ul><ul><li>L wave (long wave, surface wave, ground wave) </li></ul></ul><ul><ul><ul><li>Particles move in elliptical orbit </li></ul></ul></ul><ul><ul><ul><li>Originates on the surface after the P and S waves go straight up from the focus and reach the surface </li></ul></ul></ul><ul><ul><ul><li>The L wave causes the damage and will be the strongest at the epicenter </li></ul></ul></ul><ul><ul><ul><li>Travels the slowest </li></ul></ul></ul>Types of Waves
  16. 19. How do we Measure Earthquakes? <ul><li>Earthquake waves are recorded by a seismograph and the recording of waves on paper is called seismogram </li></ul>
  17. 20. How do we Measure Earthquakes? <ul><ul><li>Intensity – a measure of the effects on an earthquake at a particular location </li></ul></ul><ul><ul><li>Magnitude : a measure of the strength or amount of energy released during an earthquake </li></ul></ul>
  18. 21. <ul><li>Modified Mercalli intensity scale : An estimate of the intensity based on observation of actual damage </li></ul><ul><ul><ul><li>A 12 point scale using Roman numerals </li></ul></ul></ul><ul><ul><ul><li>Very dependent upon the quality of structures </li></ul></ul></ul>How do we Measure Earthquakes?
  19. 23. <ul><li>Richter Scale : Measures the amplitude of earthquake waves on seismograms </li></ul><ul><ul><ul><li>Scale from 1-10 </li></ul></ul></ul><ul><ul><ul><li>Each number is 10 times the amplitude of the number below </li></ul></ul></ul>How do we Measure Earthquakes?
  20. 26. <ul><li>Locating the epicenter </li></ul><ul><ul><ul><li>Lag time between the arrival of the P wave and the S wave to the seismograph station is converted to a distance </li></ul></ul></ul><ul><ul><ul><li>A circle with a radius that equals the distance is drawn around the station. </li></ul></ul></ul><ul><ul><ul><li>Two stations can narrow down the location to two places where the two circles intersect </li></ul></ul></ul><ul><li>Locating the focus : the lag-time of the L wave will determine the depth of the focus </li></ul>Measuring Earthquakes
  21. 28. Earthquake Dangers <ul><li>Most injuries and deaths are caused by falling objects and most property damage results from fires that start </li></ul><ul><ul><li>Tsunami : seismic sea wave sometimes generated when an earthquake originates on the ocean floor </li></ul></ul>
  22. 30. Tsunami—December 2004 http://www.bedford.k12.ny.us:16080/flhs/science/images/tsunami2004/
  23. 31. Earthquake Dangers <ul><ul><li>Seiche : rhythmic sloshing of small bodies of water </li></ul></ul>A seiche is the sloshing of a closed body of water from earthquake shaking. Swimming pools often have seiches during earthquakes.
  24. 32. <ul><ul><li>Liquefaction : unconsolidated materials that are water saturated may turn to a fluid causing some underground objects such as storage tanks to float to the surface </li></ul></ul>Earthquake Dangers Ground fissures caused by liquefaction near the mouth of the Pajaro River in California during the 1989 Loma Prieta earthquake. When the surface of the ground oscillates, wet, sandy, and muddy soils can flow like a liquid. This is liquefaction. You can liquefy wet sand at the beach by pumping it up and down with your feet. Photo courtesy of the Loma Prieta Collection, Earthquake Engineering Research Center, UC Berkeley.
  25. 33. <ul><ul><li>Landslides </li></ul></ul>Earthquake Dangers
  26. 34. Earthquake Safety <ul><ul><li>Protect yourself from falling objects ( GET UNDER SOMETHING ) or stand in a hallway or doorway (watch out for a swinging door) </li></ul></ul><ul><ul><li>Do not try to go outside during the earthquake </li></ul></ul><ul><ul><li>After the earthquake and before the aftershocks, go outside </li></ul></ul><ul><ul><li>Do not return to the building until it has been inspected </li></ul></ul>
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