1. EARTHQUAKES & SEISMIC WAVES CHAPTER 6.2

2. W HAT IS AN EARTHQUAKE ? The shaking and trembling that results from the movement of rock beneath Earth’s surface Caused by plate movement

3. W HERE DOES AN EARTHQUAKE START ? Focus: area beneath Earth’s surface where rock that is under stress breaks, triggering an earthquake Epicenter: point on the surface directly above the focus

5. H OW DOES AN EARTHQUAKE MOVE ? Seismic waves carry energy from an earthquake away from the focus, through Earth’s interior, and across the surface.

7. A RE THERE DIFFERENT TYPES OF SEISMIC WAVES ?

8. P WAVES First waves to arrive Compress and expand the ground like an accordion Crust vibrates forward and back along the path of the wave Can damage buildings Travels through solids and liquids

9. S WAVES Secondary waves Seismic waves that vibrate from side to side as well as up and down Cannot travel through liquids Shakes structures violently

10. Moves like an accordion Moves like ‘the wave’ at a football game

11. SURFACE WAVES Move more slowly than P waves and S waves, but can produce severe ground movements Can make the ground roll like ocean waves or shake buildings from side to side

13. H OW ARE SEISMIC WAVES MEASURED ?

14. W HAT ARE THE 3 WAYS TO MEASURE AN EARTHQUAKE ? 1. Mercalli scale: rates the earthquakes according to level of damage at a given place (pg 191)

15. M ERCALLI S CALE XII IN L A P AZ, B OLIVIA

16. 2. Richter Scale: rating of an earthquake’s magnitude based on the size of the earthquake’s seismic waves Magnitude of an Earthquake: a # that geologist assign to an earthquake based on the earthquake’s size

17. 3. Moment Magnitude Scale: rating system that estimates the total energy released by an earthquake

18. G EOLOGISTS USE THE SEISMIC WAVES TO LOCATE AN EARTHQUAKE ….