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Earthquakes ppt for class
An earthquake is defined as a sudden slip on a fault that leads to ground shaking and seismic energy release, primarily caused by tectonic plate movement. Key concepts include the types of faults (normal, reverse, strike-slip) and the measurement of earthquakes through seismographs and scales like the Richter and Mercalli scales. Additional information covers tsunami formation resulting from underwater earthquakes and the effects of seismic waves.
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Earthquakes ppt for class
- 1. Earthquakes What Is AnEarthquake? Click here to find out Adapted from powerpoint by Liz LaRosa http://www.middleschoolscience.com 2009
- 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, http://eqseis.geosc.psu.edu The map above shows the distribution of earthquakes with magnitudes greater than 5.0 that occurred between 1965 and 1995.
- 3. Three Types ofFaults Strike-Slip Animation of fault movement Reverse Normal
- 4. Normal fault Pulls onthe crust stretching rock so that it becomes thinner (like pulling on bubble gum) = Occurs when plates are moving apart Hanging wall Foot wall Results in hanging wall slipping downward animation
- 5. What type offault? normal Hanging wall Foot wall http://www.bgs.ac.uk/eqr/GeoD_Structures.htm
- 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? transform – What type of stress is shown? shearing
- 7. Strike – slipfault Rocks on either side of fault slip past each other sideways with little up or down motion What type of stress is produced? Occurs at a transform plate boundary Animation of strike-slip motion
- 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%2 0Reports/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 Hanging wall Foot wall Results in hanging wall slipping upward animation
- 10. What type offault? reverse Hanging wall Foot wall http://geologicalintroduction.baffl.co.uk
- 11. What type offault? http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM
- 12. Focus – 1.point inside the Earth where an earthquake begins Epicenter – 2. point on Earth’s surface above focus where earthquake is FELT most strongly 2 1
- 13. How Seismographs Work Aseismograph is an instrument used for recording the intensity and duration of an earthquake. the pendulum remains fixed as the ground moves beneath it http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM
- 14. Earthquakes • How areearthquakes measured? Seismogram – seismic wave display record Seismograph machine
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- 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
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- 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 How muchtime elapsed between the arrival of the P wave (start) and the arrival of the S wave (finish)? start http://isu.indstate.edu/jspeer/Earth&Sky/EarthCh11.ppt finish
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- 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 magnitude ___________ of an earthquake. Its values typically fall between 0 and 9, with each increase of 1 representing a 10-fold _________ increase in energy.
- 27. How are EarthquakesMeasured? Mercalli Intensity Scale A scale of earthquake intensity based on ___________ observed effects and ranging from I (detectable only with instruments) to XII (causing almost total destruction). Click for Interactive Demo Go to http://tinyurl.com/13quake13
- 28. Earthquake Waves &Earth’s Interior Seismic wave animation
- 29. Seismic Waves in the Earth Clickhere for animation http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM
- 30. Tsunamis Click here forexplanation of a tsunami http://www.uwgb.edu/dutchs/EarthSC-102VisualsIndex.HTM
- 31. Formation of atsunami a large ocean wave usually caused by an underwater earthquake or a volcanic explosion. PBS –tsunami animation http://isu.indstate.edu/jspeer/Earth&Sky/EarthCh11.ppt
- 32. With typical waves,water flows in circles, but with a tsunami, water flows straight. This is why tsunamis cause so much damage! Click here for Japan helicopter view of tsunami
- 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. Normal Reverse 3. Transverse or strike-slip
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- 39. What type offault? Source: indiana.edu http://geologicalintroduction.baffl.co.uk A Hanging wall has moved upward Reverse fault B Strike –slip or transverse fault
- 40. Focus – 1.point inside the Earth where an earthquake begins Epicenter – 2. point on Earth’s surface above focus where earthquake is FELT most strongly 2 1
- 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 3. Surface 1. P-wave 2. S-wave Seismogram 4.____________ seismic wave display record 5. Seismograph __________ machine
Editor's Notes
- #2 Liz LaRosa http://www.middleschoolscience.com 2009 for my 5th grade science class 2009
- #6 Normal fault - Results in hanging wall slipping downward
- #7 Transform plate boundary showing shearing stress.
- #11 Reverse fault – hanging wall has moved upward
- #14 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.
- #22 Approximately 5 minutes and 20 seconds.
- #40 A – reverse fault - hanging wall has moved upwardB - Strike-slip fault // Source: indiana.edu