Deck 5: Tsunami

Question 1

Which of the following is LEAST effective in mitigating the impact of tsunami?

A) Limit building in places potentially flooded by tsunami.
B) Design structures to resist erosion and scour.
C) Orient streets and buildings parallel to waves.
D) Plant trees with deep roots.
E) Build concrete walls in front of houses.

Answer 1

C

Question 2

Why do ships in the open ocean NOT notice passage of a tsunami wave?

A) The wave goes by so fast that it is gone before anyone notices.
B) The long time between wave crests dictates that the wave flanks have almost no slope.
C) Ships are carried on the crest of the wave, so they don't feel any up or down motion.
D) Although the wave crests are several hundred meters high, the time between them is several hours, so no one notices.
E) The wave hits the ship so hard and fast that no one survives to tell about it.

Answer 2

B

Question 3

Tsunami waves nearing the open coast:

A) slow down because they don't want to hit the coast too fast.
B) speed up because they finally begin to feel bottom.
C) slow down because they drag more on the shallower bottom than in the deep ocean.
D) speed up because the shallower water forces the leading edge to squirt out ahead.
E) speed up because the wave launches forward as it breaks.

Answer 3

C

Question 4

What is often the first indication of the arrival of a tsunami at the coast?

A) a giant 100-meter-high wave looming on the horizon
B) a sudden rise in sea level to a crest within about 20 seconds
C) a rapid drop in sea level
D) sea turtles running up the beach
E) people running down to the beach to see the action

Question 5

What type of event has repeatedly generated very high tsunami waves in coastal fjords of southeastern Alaska?

A) a large rockfall into the fjord
B) a giant subduction-zone earthquake
C) a massive stratovolcano eruption
D) an undersea landslide caused by liquefaction of beach sediments
E) the toe of a fast-moving glacier suddenly surging forward

Question 6

Which wave of a major tsunami is most likely to be the highest?

A) first
B) third or fourth
C) second
D) tenth
E) twentieth

Question 7

What are two main causes of tsunami?

A) volcano flank collapse and sudden degassing of the mantle from a mid-oceanic ridge
B) sudden changes in ocean-floor lithosphere velocity and major rockfall into the ocean
C) asteroid impact into the ocean and collapse of a mid-oceanic ridge
D) subduction-zone earthquakes and transform-fault earthquakes
E) subduction-zone earthquakes and landslide into the ocean

Question 8

What is the most dangerous location in a tsunami hazard?

A) a straight stretch of coast directly exposed to the open sea
B) a rocky point protruding into the ocean in deep water
C) a bay with a nice sandy beach at its end
D) a small boat in the deep ocean
E) a large boat 300 kilometers offshore

Question 9

In the open sea,tsunami reach an average wave height of about:

A) 1 or 2 meters.
B) 10 meters.
C) 100 meters.
D) 1,000 meters.
E) 10,000 meters.

Question 10

About how high are the largest earthquake-caused tsunami waves in bays?

A) about 3 meters
B) about 30 meters
C) about 300 meters
D) about 3000 meters
E) about 30,000 meters

Question 11

Which of the following submarine faults CANNOT cause tsunami waves?

A) strike-slip faults
B) normal faults
C) subduction-zone faults
D) thrust faults
E) breakaway faults of major landslides

Question 12

About how high are the largest earthquake-caused tsunami waves in the open ocean?

A) about 15 meters high
B) about 1 meter high
C) about 50 meters high
D) about 300 meters high
E) about 1 kilometer high

Question 13

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

A) Wait until the commotion dies down, and turn on the TV to find out where it happened.
B) Immediately call the nearest civil defense office to find out where it happened.
C) Carefully scan the horizon to see if a tsunami wave formed. If you see one, run inland.
D) Immediately run up slope as far as possible.
E) Immediately get into the nearest house for protection.

Question 14

As it enters a bay,the height of a tsunami wave:

A) rises because more water from each wave is forced into less space.
B) rises primarily because the bay narrows.
C) rises because of thermal expansion in the warm water of the bay.
D) drops because the wave must spread out and slow as it approaches the shore.
E) drops because as the wave breaks it rushes ahead as a fast-moving swash.

Question 15

Although the Atlantic coast of North America experiences few large earthquakes,what specific other event could generate a large tsunami wave that could cause catastrophic damage there?

A) a giant subduction-zone earthquake near the coast of Africa
B) a giant subduction-zone earthquake along the eastern edge of North America
C) a giant transform-fault earthquake on the Atlantic Ocean floor
D) flank collapse of a volcano in the Canary Islands
E) flank collapse of Mt. Vesuvius

Question 16

What are the approximate times between tsunami wave crests?

A) 30 seconds to 1 minute
B) 1 to 3 minutes
C) 10 to 35 minutes
D) 2 to 3 hours
E) 10 to 12 hours

Question 17

What are the approximate wavelengths of tsunami waves?

A) 36 meters
B) 360 meters
C) 3.6 kilometer
D) 36 kilometers
E) 360 kilometers

Question 18

What is the average speed of tsunami waves in the deep ocean?

A) 8-9 km/hour
B) 80-90 km/hour
C) 800-900 km/hour
D) the speed of an Olympic sprinter
E) the speed of light

Question 19

How are tsunami waves in the Atlantic Ocean likely to be generated?

A) by sudden rise of the Mid-Atlantic Ridge
B) by collapse of the flank of an oceanic island volcano
C) by a huge iceberg suddenly grounding on the coast of Newfoundland
D) a subduction-zone earthquake along the plate boundary just off eastern North America
E) a large-magnitude earthquake on a transform fault on the ocean floor

Question 20

What are the approximate tsunami-wave velocities over the continental shelf or near shore?

A) about 1 km/hour
B) about 10 km/hour
C) about 150-300 km/hour
D) about 700-800 km/hour
E) about 2,000 km/hour

Question 21

Explain exactly how the initial event was related to the secondary event.

Question 22

What are some measures that can be taken to minimize damages from tsunami waves?

Question 23

What was the magnitude (give the number)of that earthquake?

Question 24

h.How long was the break along that fault?

Question 25

When are tsunami warning systems ineffective?

Question 26

About how high are the largest earthquake-caused tsunami waves in bays?

Question 27

Explain how volcanoes can lead to tsunamis.

Question 28

Explain why swimming during a tsunami is not the best option to save your life.Discuss waves and effects of a tsunami on its surroundings.

Question 29

Where,specifically,was that initial event?

Question 30

Why are tsunami waves in the open ocean limited in height?

Question 31

In December 2004,a pair of closely related natural disasters killed tens of thousands of people.

Question 32

What was the specific kind of that initial event (the variety of the general event noted in part a)and the exact nature of it?

Question 33

What secondary event (the one that killed most of the people)was caused by the initial event noted above (the general name for that type of event)?

Question 34

Which is the more dangerous location in a tsunami hazard: a straight stretch of open coast,a rocky point,or a bay? Why?

Question 35

Decide which natural occurrence would create the most catastrophic tsunami and why.Describe the location that would be the most devastating.

Question 36

Why do ships in the open ocean not notice passage of a tsunami wave?

Question 37

Explain the two levels of the Pacific Tsunami Warning System and how they work.

Question 38

Discuss options to mitigate the effects of a tsunami on an area.

Question 39

How dangerous are tsunami in the open ocean,and why?

Question 40

What was the nature of the boundary marked by that fault?

Question 41

Discuss the well-known tsunami that are supposed to occur in the future and the effects of each.

Question 42

In the case of the Sumatra Tsunami in December 2004,what was the initial event that caused the tsunami? How did certain people's reactions save lives? What can education do to help further people's knowledge about this natural disaster?