1 / 28

Leaving Certificate Geography Unit 1.4 : Earthquakes

Leaving Certificate Geography Unit 1.4 : Earthquakes. Mr. McMahon. Learning Outcomes . You will learn…. What an earthquake is. Why they occur. How their global pattern is explained by the location of fault lines. . How earthquake zones are located and measured. How they are predicted.

giorgio
Download Presentation

Leaving Certificate Geography Unit 1.4 : Earthquakes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Leaving Certificate Geography Unit 1.4 : Earthquakes Mr. McMahon Mr.C.McMahon

  2. Learning Outcomes • You will learn…. • What an earthquake is. • Why they occur. • How their global pattern is explained by the location of fault lines. • How earthquake zones are located and measured. • How they are predicted. • How earthquakes impact upon the landscape and human populations. Mr.C.McMahon

  3. Earthquakes-The Past Ten Years Mr.C.McMahon

  4. What is an Earthquake ? Damage Decreases From Epicentre Scarp Mr.C.McMahon

  5. What Causes Earthquakes? • The plates of the crust are constantly moving. • Sometimes plates jam or stick together. • This creates a build up of energy when one or both plates slip releasing seismic waves that can violently shake the surface above. http://www.youtube.com/watch?v=P53OJd_lxew Mr.C.McMahon

  6. Key Concepts • Focus: The point where an earthquake begins in earth’s crust. Earthquakes can be shallow or deep focus. • Epicentre: The point on the surface that is the worst affected by a quake. Damage lessens the further one moves from the epicentre. Mr.C.McMahon New Zealand Earthquake 2011

  7. The Global Distribution of Earthquakes Mr.C.McMahon

  8. Location of Earthquakes • Earthquakes do no occur randomly. • Their location is based on plate boundaries. • Earthquakes occur at convergent, divergent and transform boundaries. Mr.C.McMahon

  9. The Subduction zone of Japan is the most earthquake prone area in the world. • Transform Fault. California USA. • Rifting: East Africa • Divergent: Mid Atlantic Ridge. • Convergent: Columbia -Chile Mr.C.McMahon

  10. Seismic waves • Primary (P) waves: Fast waves that compress then expand molten material • http://www.youtube.com/watch?v=_YLjIvJXhpg Mr.C.McMahon

  11. Secondary (S) waves are slow as they have to travel through solid rock. Mr.C.McMahon

  12. Earthquake Waves Mr.C.McMahon

  13. Surface Waves: The slowest waves that expend their energy on the surface causing anything on it to move up and down. • Principle.Energy from waves is absorbed by material as it travels through them. Thus the father a wave travels the more energy they expend. Mr.C.McMahon

  14. Measuring Earthquakes • The Seismograph • Three are needed for a full set of data • Horizontal measuring waves North-South • Horizontal- East to West. • Vertical Movement Mr.C.McMahon

  15. The Richter Scale • Logarithmic Scale. • Each unit is 10 times the wave activity of the previous for example a force 8 is 10 times greater than a force 7. • The force is measured at a greater rate of 30. http://www.youtube.com/watch?v=1qbg7orb1lc Mr.C.McMahon

  16. Predicting Earthquakes • Earthquake zones are identified. • Predictions based on timeframes. • Seismologist Identify seismic gaps- points between plates where earthquakes are likely to begin. Mr.C.McMahon

  17. Early Warning Systems • Early Warning systems based on modern communication systems are being developed. • Monitoring animal behaviour. Mr.C.McMahon

  18. Mr.C.McMahon

  19. Destruction by Earthquakes • Destruction by earthquakes depends on the following. • The depth of the focus • The population density around the epicentre. • Economic development and the standard of buildings. • Overlying Topography Mr.C.McMahon

  20. Soil Liquefaction • Liquefaction is the process of soil, clay and sand turning into a sludge. • During an earthquake ground water mixes with the soil types to produce a material like quicksand. • This undermines the foundations of bridges, roads, dams etc…. • Consequences ? Mr.C.McMahon

  21. Other Dangers • Falling Debris • Flooding • Burst gas and sewage mains. • Spread of disease • Disruption to emergency services • Tsunamis Mr.C.McMahon

  22. Tsunami • Giant waves that are generated when an earthquake occurs on the sea floor. • See Indian ocean Earthquake- Tusnami animation Wikipedia Mr.C.McMahon

  23. Limiting Earthquake Damage • Retro- fitting of Old Buildings. • The development of advanced warning systems • Tapered frames to increase a buildings frames integrity • The use of shock absorbers in a buildings columns and foundations. Mr.C.McMahon

  24. Case Study: The Haiti Earthquake • Tuesday 12th January 2010. • Measured 7.0 Richter Scale • Focus at 13 KM • Epicentre 13KM from the capital Port Au Prince www.bigpicture@boston.comHaitiearthquake Mr.C.McMahon

  25. Haitian Earthquake Map http://www.youtube.com/watch?v=1IzEYHetFUE Mr.C.McMahon

  26. Case Study: The Japan Earthquake • Struck on March 11th 2010 • Richter Scale 9.0 • Epicentre 60KM from the coast triggered Giant Tsunami • Over 12,690 dead and 14,000 unaccounted for. http://www.youtube.com/watch?v=3Uq2hA2-9oc Mr.C.McMahon

  27. http://www.youtube.com/watch?v=hOe8PMoKdI8 Japan Earthquake Map Mr.C.McMahon

  28. Key Concepts • Earthquake • Focus • Epicentre • Seismology • Seismograph • Richter scale • Magnitude • P Waves • Q Waves • S Waves • Earthquake Prediction • Early Warning Systems • Scarp • Tsunami • Tremor • Aftershocks Mr.C.McMahon

More Related