CORS 220: NATURAL HAZARDS AND DISASTER PREPAREDNESS (FALL 2006)

MIDTERM EXAM

NAME: ___________________________________ GRADE: ______ / 140

TIME AVAILABLE: 75 MINUTES

Instructions: There are TEN pages of questions. Take a minute or so now to page through the entire exam and toget a feeling for the length. READ THE QUESTIONS CAREFULLY. Think carefully about your wording, trying toavoid ambiguity and unclear answers.

PART 1: True or False (24 points)

For each of the following statements, circle whether the statement is true or false.

IF THE STATEMENT IS FALSE, provide a corrected statement.

Hint: FIVE of the statements are false.

1. The terms “hazard” and “risk” essentially mean the same thing.TRUE / FALSE

2. The worst natural disaster of all time in terms of number of fatalities was due to an earthquake in 1201 in Egypt.TRUE / FALSE

3. The largest tsunami ever recorded occurred at Lituya Bay in Alaska. TRUE / FALSE

4. A Rayleigh wave is an example of a body wave. TRUE / FALSE

5. The point in the earth where an earthquake begins is called the focus. The point on the surface directly abovethe focus is the hypocenter. TRUE / FALSE

6. The largest earthquake in the history of California was the M7.9 Fort Tejon event in 1857. TRUE / FALSE

7. Tall buildings have low vibrational frequencies so they are particularly vulnerable to low frequency surfacewaves. TRUE / FALSE

8. Strike-slip faults have produced historically large earthquakes and are therefore a clear tsunami hazard.TRUE / FALSE

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PART 2: Multiple Choice (30 points)

Circle the correct answer from those provided for each question.

1. Which of the following would NOT be considered an example of a “risk”?:(2)

( 20,000 potential fatalities / a M7.8 earthquake / $2 billion in likely damages )

2. The largest death toll for any earthquake in the United States occurred here:(2)

( San Francisco in 1906 / Northridge in 1994 / Alaska in 1964 )

3. An example of a transform plate boundary is provided by the:(2)

( Basin and Range / Himalayas / San Andreas fault )

4. Which of the following features would be expected to be found at a convergent plate boundary?(2)

( subduction zone / normal fault / transform fault )

5. Which of the following U.S. states is not considered to be prone to earthquakes?(2)

( South Carolina / Texas / Missouri )

6. A magnitude 7 earthquake releases ______ times as much ENERGY as a magnitude 6 earthquake.(2)

( 2 / 10 / 33 )

7. The 1994 Northridge earthquake and the 1971 Sylmar earthquake in Los Angeles both had this magnitude:(2)

( 6.7 / 7.8 / 9.0 )

8. Which of the following earthquake-prone U.S. cities is NOT within an intracontinental rift zone?(2)

( Salt Lake City, UT / Memphis, TN / Seattle, WA )

9. In an earthquake-prone region, just say no to:(2)

( reinforced concrete / unreinforced masonry / wood-frame structures )

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10. The eastern seaboard of the United States has a tsunami risk posed by volcanic flank collapse in this location:(2)

( Canary Islands / Big Island of Hawaii / Krakatoa )

11. The two most voluminous lava flow eruptions in historic times (Laki and Eldgja) occurred here:(2)

( Hawaii / Iceland / Indonesia )

12. Which of the following terms does not belong with the others?(2)

( ash fall / pyroclastic flow / nuée ardentes / glowing avalanche )

13. The triggering event that started the chain reaction that resulted in the eruption of Mount St. Helens wasa/an:

(2) ( lateral blast / earthquake / landslide )

14. The tallest and biggest volcanoes are typically made of basalt and are called:(2)

( shield volcanoes / stratovolcanoes / cinder cones )

15. Which of the following eruptive styles essentially means a steam-dominated eruption?(2)

( Strombolian / Vulcanian / Peléan / Phreatic )

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PART 3: Fill in the blanks (46 points)

1. The largest earthquake on record was a M9.5 event in 1960 in this country: ____________________. (2)

2. The term used to describe the average amount of time between hazard events (i.e., the repeat time), such as

between earthquakes or volcanic eruptions, is called the _______________________________. (2)

3. The most tsunami-prone city in the United States is _______________________________. (2)

4. The fastest of all the seismic waves is the __________________________. (2)

5. The record of an earthquake is provided by a graph of zig-zag lines called a _____________________. (2)

6. The distance to an earthquake is related to the time lag between the arrival of the _____ and _____ waves. (2)

7. Sometimes, a large earthquake in a region can start a domino effect of numerous subsequent earthquakes

(not aftershocks) over a period of several decades due to the disturbance created by the initial quake. This

phenomenon is called _______________________________. (2)

8. In a region undergoing compression, what do we call the type of fault that does not reach all the way up to

the surface, thus making its presence difficult to identify? ________________________________ (2)

9. The most common mechanism by which tsunamis are produced on earth: ______________________ (2)

10. The property of a lava flow that measures its resistance to downhill motion is called __________________. (2)

11. The highest death toll from a pyroclastic flow (29,000) occurred from Mt. Pelée in 1902 on the island of

____________________________ (2)

12. A volcanic mudflow is better known as a ______________________. (2)

13. The vertical plume of material from an explosively erupting volcano is called a ______________________. (2)

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14. One of the potential warning signs that indicates that a volcano is getting ready to erupt in the not-to-

distant future is: ____________________________________ (2)

15. Prior to the eruption of Mount St. Helens in 1980, the last Cascades volcano to erupt (from 1914-1917) was:

____________________________________ (2)

16. After a volcano erupts, it may start to build up material inside the crater again by oozing out viscous rhyolite

lava. The feature thus created inside the crater is called a ___________________________. (2)

17. A large flood of water caused by the eruption of a subglacial volcano is called a _____________________. (2)

18. An example of a giant continental caldera style of volcano: _____________________________ (2)

19. Loose sediment typically comes to rest at a slope angle where it is at the critical point of failure for further

downslope movement. This angle is referred to as the _____________________________. (2)

20. Landslides come in three varieties: falls, slides, and flows. Give an example of each: (6)

Fall: _____________________

Slide: _____________________

Flow: _____________________

21. Debris flows commonly occur across an existing slope of boulders and debris previously deposited near the

base of a mountain range. This type of sediment deposit is called an _____________________________. (2)

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PART 4: Short-answer questions (40 points)

From the questions shown below, choose FIVE to answer in the form of a short paragraph. Make sure youaddress ALL components of the questions you select. Use the back side of the page if you need more space.

1. Explain what is meant by seafloor spreading, how we know it exists, and what the consequences are forhazards in this type of environment. (8)

2. Explain what concept is being represented by this figure. (8)

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3. What is meant by earthquake intensity, how is it related to earthquake magnitude, and how does intensityvary relative to the epicenter of an earthquake? (8)

4. The 1906 earthquake along the San Andreas fault had both short-term and long-term effects in the SanFrancisco region. Describe some of the details of the earthquake event itself and some of its lastingrepercussions. (8)

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5. The map to the right shows the Pacific Northwest region of the U.S.A. Also shown is the approximateequivalent size of the rupture zone of the M9.1 Sumatra-Andaman earthquake on December 26th, 2004.Explain why the size of the 2004 earthquake rupture zone is relevant to the Pacific Northwest. Your answershould include details of any similarities in the tectonic setting of the two regions. (8)

6. What is being represented in this figure? Indicate the nature of the hazard involved and why it exists in thisregion. Also, indicate how we know where to plot the gray stars and what the meaning is of the red stars. (8)

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7. What phenomenon is being demonstrated in the laboratory experiment below? Describe specifically whatthe experiment is attempting to explain, and mention an enigmatic case example that was ultimately solvedusing this experiment. (8)

8. Write a short paragraph about ocean tsunamis, including their cause, their size on the open ocean relative tothe shoreline, their wavelength, tell-tale signs of their approach at a coastline, and the number of wavestypically produced. (8)

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9. The photo below shows a region where a trench was dug into coastal sediments. Describe what the scientistswere looking for, what they could see in this particular trench, and how it can be interpreted specifically.Finally, indicate a possible geographic locality where this trench may have been dug. (8)

10. What type of volcanic feature is shown in the photograph below? Explain how it forms, the type of eruptionstyle it produces, the type of volcano with which it is usually associated, and the type of rock it producesaround the vent. (8)

11. BONUS QUESTION: (8)

Answer one more of the above questions for up to 8 bonus points. Hooray!

[148 possible points]