Earthquake Lesson
- 1. Earthquakes Earth Science 11 Ms. McKean
- 2. Objectives Use the Elastic Rebound Theory to describe how Earthquakes occur. Identify the epicenter and focus of an Earthquake given a diagram. Name and describe each of the 4 types of seismic waves including movement, direction, speed, and how they attribute to Earthquake damage. Describe how Earthquakes are measured and identify which tools are used in this process.
- 3. PART 1 What are Earthquakes
- 4. What are Earthquakes? The shaking or trembling caused by the sudden release of potential energy Usually associated with faulting or breaking loose of locked plates Continuing adjustment of position results in aftershocks
- 6. Elastic Rebound Theory Explains how energy is stored in rocks Forces will cause rocks to bend until a point of deformation Rocks stay deformed as forces continue until eventually they force breaks Energy is released from the fault in waves
- 7. The Focus and Epicenter of an Earthquake The point within Earth where faulting begins is the focus The point directly above the focus on the surface is the epicenter
- 8. Seismic Waves Response of material to the arrival of energy released by rupture Two types: Body waves (P and S) Surface waves (R and L)
- 9. Body Waves P- waves (Primary Waves) Fastest moving Move like sound waves (compression) Can travel through both solids, liquids & gases S-waves (Secondary Waves) Slower than P-waves Move like a snake Can only travel through solids (not liquids)
- 10. Body Waves: P and S waves
- 11. Surface Waves: R and L waves Surface Waves Rayleigh Waves and Love Waves Travel just below or along the ground’s surface Slower than body waves; rolling and side-to-side movement Especially damaging to buildings
- 12. Seismic Waves
- 13. Faults A fault is a fracture in the Earth's crust 3 main fault groups Faults are classified depending on how they move.
- 14. Faults Normal Fault occur in response to pulling or tension the overlying block moves down the dip of the fault plane. Thrust Fault occur in response to squeezing or compression the overlying block moves up the dip of the fault plane. Strike Slip the blocks move horizontally past one another.
- 15. The Normal Fault Strike-Slip Fault Thrust Fault
- 16. Normal Fault
- 17. Thrust Fault
- 20. Check your understanding According to the Elastic Rebound Theory, what causes Earthquakes? What is the difference between the focus and the epicentre of an earthquake? What are the 4 types of seismic waves? How do each of them move? (Try and use descriptive examples). What is a fault? Name the 3 types.
- 21. PART 2 Measuring Earthquakes
- 23. The Seismograph The device which records Earth tremors The base of the seismograph is anchored to the ground A pendulum swings when the earth moves The pen attached to the pendulum records the movement
- 25. The Richter Scale Measures earthquake magnitude Based on the amplitude of the wave produced on the Seismograph Each point represents ground vibrations 10 times greater then the point before it
- 27. Check your understanding What are the two scales used to measure Earthquakes called? What does each measure specifically? What is the difference in strength between a 4 and a 6 force earthquake on the Richter Scale? Describe how a seismograph works.
- 28. PART 3 Environmental Impacts
- 29. Environmental Impacts Ground Shaking Amount depends on three factors: distance from epicentre the area’s geology the size of the Earthquake
- 31. Environmental Impacts Liquefaction the vibration of seismic waves causes groundwater to rise to the surface turns solid ground into a liquid-like material houses, building will sink into the ground
- 34. Environmental Impacts Tsunamis a very large sea wave produced by an earthquake earthquake occurs underwater earthquake happens, ground moves, water moves to fill in change in ocean floor wave results 1964 Alaskan Earthquake caused a Tsunami to travel down hit places like Port Alberni and even made it to Hawaii
- 35. Check your understanding Name three impacts Earthquakes have on the environment. Which one do you think is the most destructive and why? What does liquifaction do to the ground? Where in BC where this be a very big problem? What is a tsunami?
- 36. Quiz Now that you have finished the presentation its time test your knowledge. Be sure to read each question carefully. At the end let me know your score. Good Luck!
- 37. What is the name of the theory that describes how earthquakes occur Correct - Click anywhere to continue Incorrect - Click anywhere to continue You must answer the question before continuing Submit Clear A) Focus Theory B) Elastic Rebound Theory C) Strike-slip Theory D) Richter Theory
- 38. Where is the focus of an earthquake found? Correct - Click anywhere to continue Incorrect - Click anywhere to continue You must answer the question before continuing Submit Clear A) On the surface of the Earth where the earthquake occurs B) In the core of the Earth where the earthquake is generated C) The location that has the most damage as a result of the earthquake D) The spot within the crust where the earthquate originates
- 39. Which of the following are surface waves? Correct - Click anywhere to continue Incorrect - Click anywhere to continue You must answer the question before continuing Submit Clear A) P and S waves B) S and R waves C) R and L waves D) P and L waves
- 40. The type of siesmic wave that moves through compressions is called Correct - Click anywhere to continue Incorrect - Click anywhere to continue You must answer the question before continuing Submit Clear A) a primary wave B) a secondary wave C) a rayleigh wave D) a love wave
- 41. Waves that cause the ground to roll and as a result cause lots of damage are called Correct - Click anywhere to continue Incorrect - Click anywhere to continue You must answer the question before continuing Submit Clear A) Love waves B) Rayleigh waves C) Primary waves D) Secondary waves
- 42. How are faults classified? Correct - Click anywhere to continue Incorrect - Click anywhere to continue You must answer the question before continuing Submit Clear A) their size B) the amount of damage they cause C) where they occur D) how they move
- 43. Which is NOT a type of fault? Correct - Click anywhere to continue Incorrect - Click anywhere to continue You must answer the question before continuing Submit Clear A) Normal B) Strike-Slip C) Thrust D) Rupture
- 44. What does a siesmograph measure? Correct - Click anywhere to continue Incorrect - Click anywhere to continue You must answer the question before continuing Submit Clear A) Intensity B) Magnitude C) Amount of Damage D) Size of possible tsunami
- 45. Match the environmental impact on the left to the descriptor on the right. Column 1 Column 2 Correct - Click anywhere to continue Incorrect - Click anywhere to continue You must answer the question before continuing A. large wave generated as a result of underwater earthquake B. causes building to sink C. amount depends on the distance from the epicenter B Liquifaction C Ground Shaking A Tsunami Submit Clear
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