Download to read offline
6th-20earth-quakes-notes-131215134342-phpapp01.pptx
- 1. Earthquakes Adapted from powerpointby Liz LaRosa http://www.middleschoolscience.com 2009 What Is An Earthquake? Click here to find out
- 2. What is anearthquake? • Used to describe both sudden slip on a fault, and the resulting ground shaking and radiated seismic energy caused by the slip • Caused by volcanic or plate activity, The map above shows the distribution of earthquakes with magnitudes greater than 5.0 that occurred between 1965 and 1995. http://eqseis.geosc.psu.edu
- 3. Three Types ofFaults Strike-Slip Normal Reverse Animation of fault movement
- 4. Normal fault Pulls onthe crust stretching rock so that it becomes thinner (like pulling on bubble gum) = tension Occurs when plates are moving apart Results in hanging wall slipping downward Hanging wall Foot wall animation
- 5. What type offault? Hanging wall Foot wall http://www.bgs.ac.uk/eqr/GeoD_Structures.htm normal
- 6. What causes earthquakes? •Tectonic plates move past each other causing stress. Stress causes the rock to deform – What type of fault boundary is this? – What type of stress is shown? transform shearing
- 7. Strike – slipfault Rocks on either side of fault slip past each other sideways with little up or down motion - Animation of strike-slip motion Occurs at a plate boundary transform shearing What type of stress is produced?
- 8. Fault rupture acrossroad in western Kaynasli, right-lateral strike slip displacement was about 4.0 m (13 feet) at this location http://www.geerassociation.org/GEER_Post%20EQ %20Reports/Duzce_1999/kaynasli1.htm
- 9. Reverse fault Pushes onthe crust squeezing rock until it folds or breaks (like a trash compactor) = Occurs when plates are moving together Results in hanging wall slipping upward Hanging wall Foot wall animation compression
- 10. What type offault? Hanging wall Foot wall http://geologicalintroduction.baffl.co.uk reverse
- 11. What type offault? http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM
- 12. – 1. pointinside the Earth where an earthquake begins – 2. point on Earth’s surface above focus where earthquake is FELT most strongly Epicenter Focus 1 2
- 13. How Seismographs Work http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM thependulum remains fixed as the ground moves beneath it A seismograph is an instrument used for recording the intensity and duration of an earthquake.
- 14. Earthquakes • How areearthquakes measured? Seismograph machine Seismogram – seismic wave display record
- 15.
- 16. Primary Waves (PWaves) • A type of seismic wave that compresses and expands the ground • The first wave to arrive at an earthquake http://daphne.meccahosting.com/~a0000e89/insideearth2.htm
- 17. Secondary Waves (SWaves) • A type of seismic wave that moves the ground up and down or side to side http://daphne.meccahosting.com/~a0000e89/insideearth2.htm
- 18.
- 19. Surface Waves • Movealong 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 Animation of wave types
- 20. How do scientistscalculate 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
- 21. Typical Seismogram http://isu.indstate.edu/jspeer/Earth&Sky/EarthCh11.ppt start finish Howmuch time elapsed between the arrival of the P wave (start) and the arrival of the S wave (finish)?
- 22.
- 23.
- 24. Now you aregoing to be seismologists and locate an Earthquake http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM Go to: http://tinyurl.com/11quake13 Click here to go to virtual earthquake site
- 25. National Geographic earthquakeinformation
- 26. How are EarthquakesMeasured? Richter Scale A logarithmic scale used to express the total amount of energy released ___________ of an earthquake. Its values typically fall between 0 and 9, with each increase of 1 representing a _________ increase in energy. magnitude 10-fold
- 27. How are EarthquakesMeasured? Mercalli Intensity Scale Click for Interactive Demo Go to http://tinyurl.com/13quake13 A scale of earthquake intensity based on ___________ and ranging from I (detectable only with instruments) to XII (causing almost total destruction). observed effects
- 28. Earthquake Waves &Earth’s Interior Seismic wave animation
- 29.
- 30. Tsunamis http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM Click here forexplanation of a tsunami
- 31. Formation of atsunami http://isu.indstate.edu/jspeer/Earth&Sky/EarthCh11.ppt PBS –tsunami animation a large ocean wave usually caused by an underwater earthquake or a volcanic explosion.
- 32. Click here forJapan helicopter view of tsunami With typical waves, water flows in circles, but with a tsunami, water flows straight. This is why tsunamis cause so much damage!
- 33.
- 34. Review Questions 1. Alarge ocean wave usually caused by an underwater earthquake or a volcanic explosion. tsunami 2. Used to describe both a sudden slip on a fault, and the resulting ground shaking and radiated seismic energy caused by the slip earthquake
- 35. How are EarthquakesMeasured? 3. Which one uses a logarithmic scale to express the total amount of energy released or magnitude of an earthquake. Richter Scale 4. Which uses a scale of earthquake intensity based on observed effects and ranging from I (detectable only with instruments) to XII (causing almost total destruction). Modified Mercalli Scale
- 36. What type offault is shown by each picture? 1. 2. 3. Normal Reverse Transverse or strike-slip
- 37. Which type ofwave travels through solids only? S-wave
- 38. Which type ofwave causes the most destruction? Surface or Love waves
- 39. What type offault? A Hanging wall has moved http://geologicalintroduction.baffl.co.uk B Source: indiana.edu Reverse fault upward Strike –slip or transverse fault
- 40. – 1. pointinside the Earth where an earthquake begins – 2. point on Earth’s surface above focus where earthquake is FELT most strongly Epicenter Focus 1 2
- 41. People walk alonga damaged road in the province of Bohol on Tuesday, October 15, 2013. Do you think this was a major earthquake? Why or why not?
- 42. Yes, it wasa major quake. It crumbled a number of buildings Such as this church 7.1 magnitude earthquake hit the Philippines
- 43. Earthquakes 5. __________ machine ____________ seismic wave displayrecord Seismograph P-wave Surface 2. 3. 4. 1. S-wave Seismogram
Editor's Notes
- #1 Liz LaRosa http://www.middleschoolscience.com 2009 for my 5th grade science class 2009
- #3 Three types of faults Form depending on type of plate motion and complex reaction of earth’s lithospheric blocks Strike-slip Normal Thrust
- #5 Normal fault - Results in hanging wall slipping downward
- #6 Transform plate boundary showing shearing stress.
- #10 Reverse fault – hanging wall has moved upward
- #13 Contrary to intuition, an earthquake does not make the pendulum swing. Instead, the pendulum remains fixed as the ground moves beneath it. A pendulum with a short period (left) moves along with the support and registers no motion. A pendulum with a long period (right) tends to remain in place while the support moves. The boundary between the two types of behavior is the natural period of the pendulum. Only motions faster than the natural period will be detected; any motion slower will not.
- #21 Approximately 5 minutes and 20 seconds.
- #39 A – reverse fault - hanging wall has moved upward B - Strike-slip fault // Source: indiana.edu