Natural Disasters

Prof. Stephen A. Nelson

Homework III. Volcanological Exercises

1. In your work as an insurance company executive you have been reassigned to head up the Tacoma, Washington office of  Denyallclaims Insurance Co.  Although Tacoma is located about 50 miles from the volcanic mountain, Mount Rainier, other executives in Denyallclaims have assured you that the volcano has not erupted for a long time and there is no risk associated with the volcano.  In fact, the current manager of the office, has offered to sell you his home in the suburb of Orting, Washington, for what seems to be a good price.  You decide to check things out for yourself, and go to the internet to search for hazards associated with Mt. Rainier, Washington.  The following are questions you (and your professor) want answered.

1. When was the last time Mt. Rainier had an eruption? (1 point)
    
2. Are there any types of volcanic hazards associated with Mt. Rainier that could affect you in the future if you were living in the area of Tacoma or its suburbs?  If so, what types of hazards have affected the Tacoma area in the past? (1 point)
    
3. Considering that the summit area of Mt. Rainier is covered to a large extent by glacial ice, would residents of the Tacoma area be threatened in any way by a small eruption from the volcano that only sent a few lava flows down the flanks, none reaching more than 1 km from the summit?  If so, why, and if not, why not? (2 points)
    
4. Among the things you should be able find is a hazards map for the area around Mount Rainier. This map is in PDF format, so make sure you have the Adobe Acrobat Reader installed on your computer.  The link is http://vulcan.wr.usgs.gov/Volcanoes/Rainier/Publications/FS065-97/FS065-97_map.pdf  (You might want to print this map if you cannot see the whole map  on your computer screen. If you don't have a color printer, keep the color image on your monitor so you can interpret the various color codes on the printed black and white version).  What hazards exist in Orting, Washington where the Denyallclaims manager has offered to sell the house?  How often do events represented by this hazard occur?  (1 point)
    
5. Find a site on the internet that discusses Orting, Washington.  Describe the location of Orting in terms of its topography and location relative to rivers, and discuss why this location could be particularly at risk (1 point)
    
6. What steps have been taken in Orting to reduce risk? (1 point)
    
7. How have the residents of Orting reacted to the possible hazard? (1 point)
    

2. Use the internet to answer the following questions (Note that you might have to find more than one article on the internet to answer both questions):
   
   
   1. What possible volcanic event could occur in the Canary Islands (off the northwest coast of Africa) that could have a disastrous effect on the east coast of the United States?  (Try the key words - Canary  - Islands  - disaster) Describe the possible event and the possible effects it would have on the United States. (2 points)
       
   2. How much warning would U.S. east coast cities have to prepare for the event if it occurred? (1 point)
       

3. Go the following web site: http://www.agiweb.org/geotimes/may00/featurestory.html read the article entitled: "Mount St. Helens 20 Years Later: What we have learned".  Then answer the following questions.

1. Give a summary of the sequence of events that occurred at Mount St. Helens beginning at about 8:32 AM on May 18, 1980 and ending on May 19. (2 points)
    
2. Which one of these events was the main cause of human fatalities? (0.5 point)
    
3. How many people died as the result of the eruption? (0.5 point)
    
4. What three important lessons were learned form the eruption (summarize in your own words? (2 points)
    
5. What is probably the most far-reaching scientific finding from the eruption?  Why is this important? (1 point)
    
6. Were scientists aware of the fact that Mount St. Helens could have a devastating eruption in the years prior to the 1980 event? (0.5 point)
    
7. Where volcanic hazards studies and programs well-funded prior to the Mount St. Helens event and did anything change after the event? (1 point)
    
8. What was the approximate economic loss due to the 1980 eruption? (0.5 point)
    
9. What factor(s) most strongly influence awareness of and increased funding levels for volcanic hazards studies (and natural hazards studies in general)? (1 point)
    

4. Some volcanic eruptions have occurred within the last several million years that are larger and more destructive than anything a human being has ever witnessed, or at least lived to write about.  These volcanoes erupt  between 100  and 1000 km³ of magma, mostly in the form of Plinian tephra falls and pyroclastic flows (ignimbrites) and result in the formation of large collapsed areas, called calderas.  Three of these volcanic centers have erupted within what is now the United States in the last 1.2 million years.  These are - Long Valley Caldera, Yellowstone Caldera, and Valles Caldera.  This exercise asks you to learn about one of these large rhyolitic eruptive centers, Long Valley Caldera.  A good starting point is located at http://quake.wr.usgs.gov/VOLCANOES/LongValley/index.html

1. Where is Long Valley Caldera located? (0.5 point)
    
2. When did Long Valley Caldera form? (0.5 point)
    
3. How much magma was erupted from the Long Valley system during the Caldera forming eruption? (0.5 point)
    
4. How far east is ash from this eruption still found today? (1 point)
    
5. Where and when was the most recent volcanic activity in the Long Valley area? (0.5 point)
    
6. Is there any indication that the Long Valley magma system is still active? If so, what evidence is there that the system is still active and that volcanic activity is likely to continue into the near future? (1 point)

5. Volcanoes that produce gigantic eruptions like those that occurred at Long Valley Caldera and Yellowstone (discussed in class) have recently been termed supervolcanoes.   Eruptions of supervolcanoes have the potential of producing world-wide catastrophic disasters.   Use the internet to determine if there have been any supervolcano eruptions in the last 100,000 years that could have been large enough to affect humans on a global scale.   If you can find one, where is it, when did the eruption occur, and what were the likely effects on human populations (3 points).
    
6. Go to the Volcano World site, run by the University of North Dakota: http://volcano.und.nodak.edu/.   On this site is a section called "Ask a Volcanologists" where people have written in asking some pretty basic questions about volcanoes.  Some the questions that have been asked are probably questions that you have been thinking about during our discussion of volcanoes.  The "Ask a Volcanologist" section has been discontinued, but  these questions have already been answered by the Volcano World scientists, and are still available on the web site. Use this section to find the answers to the following questions.  You might also learn some other things as well by reading through some of the other questions.
   
   
   1. For volcanic eruptions that have killed more than 500 people throughout recorded history, give the name of the volcano, the year it erupted with deadly consequences, and the major cause of death.  What three types of activity appear to cause the most deaths? (2 points)
       
   2. How could one predict if a volcano will erupt pyroclastic material or lava flows in its next eruption? (1 point)