2. Monitoring Earthquakes Chapter 2 Section 3

3. Objectives F.2.3.1. Explain how a seismograph works. F.2.3.2. Describe how Geologists monitor faults. F.2.3.3. Explain how seismograph data is used.

4. The Seismograph Seismic waves cause the seismographs drum to vibrate but the suspended weight with the pen attached moves very little. Therefore the pen remains still and records the vibrations on the drum.

5. The Seismograph When the ground shakes, it shakes the base of the seismograph but the pen stays steady because the heavy weight will tend to stay still because of its resistance to motion.

6. Reading A Seismogram Which type of wave is fastest? Second Fastest? Slowest?

7. Seismogram Which wave arrives first? Primary Why? Because it is the fastest wave.

8. Seismogram Which wave arrives second? Secondary Why? They are slower than primary waves.

9. Seismogram Which waves arrive last? Surface Waves. Why? They are the slowest. What is significant about Surface Waves?

10. They Are The Most Destructive!

11. Instruments To Monitor Faults To monitor faults, scientists have developed instruments to measure changes in elevation, tilting of the land surface, and ground movements along fault boundaries.

12. Instruments To Monitor Faults These instruments are called: Tilt Meters Creep Meters Laser Ranging Devices Global Positioning Satellites

13. Tilt Meters

14. Tiltmeter A tiltmeter measure changes in the angle of the ground from horizontal.

15. Tiltmeter

16. Creepmeter A creepmeter uses a wire stretched across a fault. On one side the wire is anchored to the ground and on the other side it is attached to a weight that can slide along a scale.

17. Creepmeter

18. Installation Of A Creepmeter

19. Laser Ranging Devices

20. Laser Ranging Devices use a beam of light to measure movements in Earth’s Plates.

21. Laser Ranging Devices From The Earth To The Moon

22. Global Positioning System GPS can be used to measure changes in the position of receivers located on opposite sides of a fault. They can be accurate to 1 mm in the horizontal and 5 mm in the vertical.

23. GPS

24. GPS Triangulation Triangulation looks at at least ____ reference points to determine precise locations of the receivers. 3

25. Seismographic Data Seismographs and fault monitoring devices are used for: Mapping Faults and detecting changes. Develop a method of predicting earthquakes.

26. Mapping Faults Faults are often hidden because they are deep underground. When seismic waves encounter faults they are reflected to reveal the faults location.

27. Monitoring Changes On Faults Geologists need to know about changes along a fault to ESTIMATE earthquake risk. Faults that move easily tend to be low risk, faults that get stuck can be very high risk.

28. Predicting Earthquakes Can scientists predict earthquakes? Absolutely not! As of today, Geologist can only estimate risk for certain areas.

29. Assessment Of Objectives F.2.3.1. This objective is fair game for the quiz. How does a seismograph record the ground shaking of an earthquake?

30. F.2.3.1.

31. F.2.3.2 What are some ways scientists are able to monitor faults? Tiltmeters Creepmeters Laser Ranging Devices Global Positioning Systems

32. F.2.3.3. What do scientists use seismic data for? Mapping faults Monitoring changes along fault lines. Predicting earthquakes. This objective is fair game for the quiz.

33. Predicting Earthquakes Can Geologists predict the time and or location of earthquakes? Can you predict for me right now the time and location of the next automobile accident in Waukegan. Not a chance.

34. Assessing Risk Based on research and observation, could we determine which roadways and intersections are at a higher risk for accidents? Absolutely This is about the best earthquake prediction we can get to at this time.