McMaster University

EARTH SC 2gg3

iClicker Questions

1)Why do most fatalities from natural disasters occur in Asia?

1. Because Asia is a continent with a developing economy.
2. Because most of the earthquakes and volcanoes occur in Asia.
3. Because Asia is the most populated continent
4. I don’t know

2. Can a hydro-meteorological disaster cause a geophysical disaster?

1. Yes
2. No

3. Which layer does not consist of mantle?

1. Asthenosphere
2. Lithosphere
3. Crust
4. I don’t know

4. Which plate will be more dynamic? (No answer – all can be right)

1. A large plate
2. A small plate
3. It depends on the location of the plate
4. I don’t know

5. Which type of boundary is the best environment for earthquakes?

1. Convergent
2. Divergent
3. Transform
4. I don’t know

6. Will California eventually fall off the ocean?

1. Yes
2. No (a continental plate cannot go under and oceanic plate)
3. It depends on…

4. I don’t know

7. If you find a well-exposed fault that moved before seismographs were available, you can infer the approximate magnitude of earthquake by measuring the

                      .

1. Largest size tree snapped off by the shaking
2. Average size of the largest rocks moved in the earthquake
3. Strength of the rocks that the earthquake managed to break
4. Total length of fault break during the event

8. What does the Richter Magnitude Scale depend on?

1. The maximum amplitude of earthquake waves on a seismograph
2. The frequency of P waves recorded on a seismograph
3. The intensity of shaking during the earthquake
4. The amount of destruction by the earthquake

9. For very long fault such as those in westernmost North America, what historic information can be used to infer where the next large earthquake may be?

1. The part of the fault with the mot frequent earthquakes
2. The part of the fault that creeps slowly and may be building to a sudden break
3. The part of the fault where there is a seismic gap
4. The part of the fault with the largest earthquake in the past

10. Which of the following submarine faults cannot cause tsunami waves?

1. Strike-slip faults
2. Normal faults
3. Thrust faults
4. I don’t know

11. Which is the most dangerous location for a tsunami hazard?

1. A straight stretch of coast directly exposed to the open sea
2. A rocky point protruding into the ocean in deep water
3. A bay with a nice sandy beach at its end
4. A boat in the deep ocean

12. What are two main causes of tsunamis

1. a) Volcano flank collapse and sudden degassing of the mantle from a idoceanic ridge
2. Asteroid impact into the ocean and collapse of a mid-oceanic ridge
3. Subduction-zone earthquakes and transform-fault earthquakes
4. Subduction-zone earthquakes and landslides into the ocean

13. If you are at the beach and feel a large earthquake, what should you do?

1. Wait until the commotion dies down, and turn on the TV to find out where it happened
2. Carefully scan the horizon to see if a tsunami wave is formed, if you see one, run inland
3. Immediately run up slope as far as possible
4. Immediately get into the nearest house for protection

14. The best tectonic environment for a violent volcano is:

1. Divergent boundary
2. Convergent boundary
3. Transform boundary
4. Hotspot

15. What two main factors result in more violent eruptions?

1. More water and higher viscosity of the magma
2. Higher viscosity and narrow enough vent
3. Strong rocks around the vent and more water
4. A large enough volcano with low-viscosity magma

16. Which of the following is NOT true?

1. Subduction zones and areas where ocean floor descends into the mantle
2. Subduction zone activity includes very large earthquakes
3. Subduction zone activity leads to active volcanoes
4. Subduction zones are areas where ocean floor rocks are formed

17. Why do shield volcanoes have very gently sloping sides?

1. Their andesite composition produces huge ash flows that spread over large area
2. Their andesite and rhyolite have low viscosity because of their water content and spread over a low slope
3. Their basalt flows have low viscosity so the lava solidifies as gentle slopes
4. Their basalt ash spreads out widely in the strong winds over the open ocean

18. If an ash flow approaches you from across a kilometer wide lake, are you likely to be safe or not?

1. Safe. Hot ash flows would chill and stop as soon as they hit cold water.
2. Safe. Ash flows move along the ground; they would continue harmlessly underwater.
3. Not safe. A fast-moving ash flow would cause a deadly tsunami wave.
4. Not safe. Ash flows can cross much wider bodies of water.