8. What causes the up and down wiggles on the seismogram shown above?

A. tsunami waves
C. electromagnetic pulses
B. ground vibrations
D. variations in air pressure

9. Which set of waves are probably the surface waves?

A. Wave A
C. Wave C
B. Wave B
D. They are all surface waves

10. Which set of waves are the P waves?

A. Wave A
B. Wave B
C. Wave C
D. They are all P waves

11. Which set of waves are the S waves?

A. Wave A
B. Wave B
C. Wave C
D. They are all S waves

12. Which of the following earthquake waves can travel through both solids and
fluids?

A. P waves only
C. Q-waves only
B. S waves only
D. Both P and S waves

13. What do you call the motion or vibration of earthquake that travels outward
from the focus?
A. chemical energy
C. gravity waves
B. electromagnetic waves
D. seismic waves

14. In the upper part of the mantle, the earthquake waves slow down It is explained that

A. that outer core is solid
B. rocks are partially molten
C. at depth the rocks are denser.
D. rocks confined at that particular location tightly packed together.

15 Which of the following statements BEST describes Secondary Waves (S-waves)?

A. circular motions like an ocean wave
B. snake like motions parallel to the Earth's surface
C. contractions and expansions that are in the direction of wave propagation
D. shearing motions that are at right angles to the direction of wave propagation​