Chapter 13

sound light seismic heat 1. An earthquake is caused by sudden release of ___ waves when rocks fail along a geologic fault. sound light seismic heat

2. The point within Earth where seismic waves originate is called the: focus. epicenter. fault scarp. fold.

3. Most earthquakes are ______. shallow focus (<70 km) intermediate focus (70–350 km) deep focus (350–670 km) very deep focus (>670 km) Earthquake foci are evenly distributed with depth

4. The first seismic wave detected by a seismomograph is a: P wave. S wave. Love wave. tidal wave.

5. On the seismograph below, which deflection represents the arrival of the P waves?

6. On the seismograph below, which deflection represents the arrival of the S waves?

7. Amplitude is measured as the height of deflection ____. B A B C D

8. Which of these are body waves? P waves S waves Love waves Rayleigh waves A and B are correct. All of the above.

9. Which type of body wave travels the fastest? S wave P wave They travel at the same speed.

10. Which body wave travels through solids and liquids? S wave P wave They both do.

11. An earthquake with a magnitude of 5 is ___ times as powerful as one with magnitude 4. 0.25 2 10 100

12. Which is an index of earthquake shaking intensity? Richter scale moment magnitude modified Mercalli index All of these measure shaking.

13. Modified Mercalli intensity does not linearly decrease away from the epicenter because local shaking intensity varies with: type of rock in the local bedrock. presence or absence of faults in the local bedrock. thickness of the local bedrock. All of the above.

14. Where would be the least likely place to experience earthquakes? convergent plate boundaries divergent plate boundaries transform plate boundaries far from plate boundaries earthquakes are equally likely at all locations.

subduction convergent 15. The deepest earthquakes are associated with what type of tectonic boundary? divergent transform collision convergent subduction convergent

16. What type of earthquakes occur along mid-ocean ridges? shallow focus (<70 km) intermediate focus (70–350 km) deep focus (350–670 km) very deep focus (>670 km) All depths occur here.

17. Sea waves initiated by seismic energy from earthquakes are called: tidal waves. tsunamis. liquefaction waves. current waves.

18. Earthquake forecasting is difficult to do with a high degree of precision because: individual faults within a regional fault system have different rupture probabilities. indicators of strain buildup are not direct indicators of rupture timing. differentiating foreshocks, mainshocks, and aftershocks is not always possible until after the fact. a swarm of small earthquakes can, but do not always, herald a larger event. All of the above.

fire ground movement liquefaction All of the above. B and C only 19. If you were a saber-toothed cat, which of the following earthquake effects could impact you? fire ground movement liquefaction All of the above. B and C only

on a former landfill site at the base of a mountain 20. If you wanted to build a multimillion dollar home in California, where should you put it? on a sea cliff on a former landfill site at the base of a mountain in the middle of a flat area